
           Linux Gazette... making Linux just a little more fun!
                                      
         Copyright © 1996-97 Specialized Systems Consultants, Inc.
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                       Welcome to Linux Gazette! (tm)
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                                 Published by:
                                       
                               Linux Journal
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                             Table of Contents
                          December 1997 Issue #23
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     * The Front Page
     * The MailBag
          + Article Ideas
          + Help Wanted
          + General Mail
     * More 2 Cent Tips
          + Spinning Down Unused HDs
          + Finding What You Want with find
          + Cutting and Pasting Without a Mouse
          + Slow Modem
          + Finding Strings with find
          + Another Calculator Tip
          + Upgrading a Laptop Hard Disk
          + Wallpaper
          + PostScript
          + Linux Virtual Console Key Sequences
          + Netscape Hidden "Easter Eggs"
     * News Bytes
          + News in General
          + Software Announcements
     * The Answer Guy, by James T. Dennis
          + Running Multiple Instances of X
          + VC Madness
          + Linux and OSPF
          + Security Problems with pop3
          + Cryptographic System
          + An Interesting De-Referencing Problem
          + Reminder!
          + pcmcia ide Drives
          + KDE BETA 1
          + Compression Program
          + loadlin
          + WipeOut
     * Boulder Linux Users Group, by Wayde Allen
     * Clueless At The Prompt, by Mike List
     * COMDEX/Fall '97, by Carlie Fairchild
     * Configuring procmail with The Dotfile Generator, by Jesper
       Pedersen
     * Graphics Muse, by Michael J. Hammel
     * Linux Benchmarking: Part 2 -- Practical Concepts, by André D.
       Balsa
     * New Release Reviews, by Larry Ayers
          + Comfortable Ftp
          + TkMan
     * Processes on Linux and Windows NT, by Glen Flower
     * Roll your own DBMS?!?, by Idan Shoham
     * Unioncamere Emilia-Romagna: an Italian Public Administration Using
       Linux, by Giamaolo Montaletti
     * Weekend Mechanic, by John Fisk
     * x3270 and Linux, by Chris Mason
     * The Back Page
          + About This Month's Authors
          + Not Linux
       
   The Answer Guy
   The Weekend Mechanic
     _________________________________________________________________
   
   The Whole Damn Thing 1 (text)
   The Whole Damn Thing 2 (HTML)
   are files containing the entire issue: one in text format, one in
   HTML. They are provided strictly as a way to save the contents as one
   file for later printing in the format of your choice; there is no
   guarantee of working links in the HTML version.
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   Got any great ideas for improvements! Send your comments, criticisms,
   suggestions and ideas.
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   This page written and maintained by the Editor of Linux Gazette,
   gazette@ssc.com
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    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                                The Mailbag!
                                      
                    Write the Gazette at gazette@ssc.com
                                      
                                 Contents:
                                      
     * Article Ideas
     * Help Wanted
     * General Mail
     _________________________________________________________________
   
                               Article Ideas
     _________________________________________________________________
   
   We're back in business after a one month gap--no November issue--and
   we need articles from you.
   
   So, all you budding authors and Linux users out there, send me your
   material. Don't depend on our regular authors to fill the gap. We want
   to hear about all the neat tips and tricks you've found, as well as
   all the neat applications you are writing or working with. We also
   like to hear how you are using Linux as a workplace solution. --Editor
     _________________________________________________________________
   
   Date: Mon, 06 Oct 1997 01:40:46 +0100
   From: Emmet Caulfield emmet@indigo.ie 
   Subject: Newbie Stuff
   
   Hi,
   
   I've noticed recently that there's an increasing volume of questions
   on fairly elementary topics to your help page.
   
   There's probably a fairly large volume of readers, like myself, who
   correspond with the querants offering help, pointers, and suggestions
   in the hope that they may be useful. I'm NOT an expert, by any stretch
   of the imagination, being a recent "convert" of only 10 months
   vintage.
   
   I think that there is an argument for the Gazette running a series of
   articles outlining a step-by-step setup procedure specifically
   targetted at people setting up Linux on home machines connected over
   the POTS in spite of the fact that this would be duplicating efforts
   elsewhere (in HOWTOs and such).
   
   Just a suggestion.
   
   I love the Gazette, you have struck a fine balance well - there is
   something for everyone. I read 22 "cover to cover".
   
   Keep up the good work,
   
   Emmet
     _________________________________________________________________
   
   Date: Wed, 15 Oct 1997 18:28:05 -0700
   From: Todd Martin zombie@ted.org 
   Subject: System Back up
   
   I would love to see an article on backing up a Red Hat 4.2 system onto
   a SCSI Tape drive.
   
   I'm having trouble with it, and am finding information on it rare if
   not impossible to find.
   
   If anyone could point me in the right direction I would appreciate it.
   
   Or contact me direct if its easy enough to explain.
   
   Thanx
     _________________________________________________________________
   
   Date: Mon, 13 Oct 1997 21:13:24 -0500
   From: "Cochran" scochran@shoalsnet.com 
   Subject: Article Idea
   
   Hello, I'm a Linux newbie so please forgive any inaccuracies. :) I
   think someone should report on the Linux game scene. Different
   projects that are dealing with game projects like GGI and the Linux
   GDK. Keep the good work up everyone.
   
   Micah
     _________________________________________________________________
   
   Date: Tue, 14 Oct 1997 18:54:41 -0500
   From: Glenn Meuth manderflawaxe@Dynasty.Net 
   Subject: LJ Howto get TECH Info for NEWBIES
   
   I have been reading LJ recently, and I would like to request that an
   article be written. I have recently had (2) problems which I
   researched, and only seemed to find dead ends for. I purchased a new
   computer recently :-) and, as is probably common with such, had some
   unsupported hardware. This did not surprise me, having worked with
   computers for some time. So I proceeded to search hardware listings,
   currently active projects, etc in order to find an answer, and found
   nothing. (My problem was with my UDMA harddrive controller card from
   Promise.) I began to email news groups and Promise trying to get the
   information I needed to write the code for the controller card myself.
   I could not seem to dig up any help on the subject of support for new
   hardware. My question: Could you please address an article on how to
   go about attaining the information necessary to code this? Q(2) Could
   you also address how to get involved in the linux project?
   
   I have tried to get involved with projects (I am a relatively new C++
   programmer (2 years)), in college, and there is little for me to do in
   my area of the USA in order to exercise my C & C++ skills. If you
   could help me out here I would appreciate it!
   
   Glenn Meuth
     _________________________________________________________________
   
   Date: Wed, 5 Nov 1997 04:11:55 -0800 (PST)
   From: Ron Culver ronc@earthlink.net 
   Subject: COMMENTS/SUGGESTION
   
   Hi Folks,
   
   First want to say I'm really glad the Gazette is on line... what a
   great source for finding out new things! Keep up the great work - it's
   a real winner. Next, want to suggest some needs on this end you might
   find useful as an idea for a feature. I run a real tiny ISP biz in NM
   (my hometown, but live in CA) - and have LOTS of questions related to
   running the system (do sysadmin via telnet) - primarily system
   security issues, keeping the email system running right, HTTPD
   (actually run Apache) questions, and DNS issues. What has most plagued
   me is the lack of a fresh source of info to keep the system on the
   'cutting edge' of new developements in software. One example is Java,
   something that came along shortly after the server was first
   installed, which I can not seem to get to run properly - and to date
   no one can tell me why. What I would like to see you try is a column
   that addresses the questions/concerns of small POP's or ISP's -
   actually anyone who is running Linux as a server on line would have
   similar questions/concerns.
   
   Have a nice....
   
   Ron Culver
     _________________________________________________________________
   
                                Help Wanted
     _________________________________________________________________
   
   Date: Sun, 12 Oct 1997 02:34:26 +0200
   From: Guillermo S. Romero famrom@ran.es 
   Subject: Clipboard Ideas
   
   Hello:
   
   I am a bit new to Linux and my programming skills are poor (time
   solves everything), but I have brain (well, 2 overclocked neurons) and
   I think that Linux (and Unix) have a problem with "cut & paste", aka
   clipboard. GPM is fine, xclipboard too, some other systems also work,
   but its hard to move from one system to another, and not all data can
   be copied.
   
   I want to start a team to implement a clipboard in Unix, maybe using
   files stored under something like /tmp/clip/ (or another /dev/foo?).
   :]
   
   The main thing is that it should be able to work with text, graphics
   and binary (archives, ie), like other OS do. I think that if we use a
   system based in /dev/ , the system will support old apps (you only
   have to save to the correct place emulating an app behaviour, and a
   demon will convert non standard files to the ones supported by the
   clipboard). We can even made the new clipboard a multiuser one. Or one
   with multiple buffers per user (like Emacs, doesn't it?).
   
   If someone is interested, just write. I have a draft so we can start
   the discussion now. I must admit that my idea maybe look mad or too
   simple, but that only demonstrates that I believe that usefullnes is
   directionaly proportional to simplicity. :]
   
   GSR
     _________________________________________________________________
   
   Date: Tue, 18 Nov 1997 11:10:08 -0500
   From: Dan E. Collis dcollis@marine.usf.edu 
   Subject: Adaptec 2940 UW adapter
   
   I am drowning! Have called Adaptec to no avail. They say they're not
   supporting Linux. Have tried all the loc's on redhat.com that I can
   find and have had no luck.
   
   Is there a driver available for an Adaptec 2940UW that's good for
   RedHat 4.2? I'd sure appreciate some help on this one.
   
   Many thanks,
   
   dcollis@marine.usf.edu
     _________________________________________________________________
   
   Date: Mon, 10 Nov 1997 12:23:45 -0700
   From: Chad Peyton chadly@cs.WNMU.EDU
   Subject: PPP
   
   I'm trying to configure a ppp connection. So far the program mgetty
   has got most things working. I don't know much about Linux, but this
   is what I think I need to do: get the shell to run the following
   command.
   
   Puser - - /usr/sbin/pppd auth -chap +pap login kdebug 7 debug
   
   But notice the message I get below when I call in:
   
   Red Hat Linux release 4.2 (Biltmore) Kernel 2.0.27 on an i486
   
   login: chad
   Password:
   Last login: Fri Nov 7 15:36:54 on ttyS0
   Warning: no access to tty (Not a typewriter).
   
   Thus no job control in this shell. It says that the shell isn't
   working or something. Do I need to get tty working or what? How do I
   do that?
   
   Also, after I logout the program quits on me. Is there a way to make
   mgetty keep working after someone hangs up? Also is there a way to
   make mgetty load at boot time?
   
   Can you help me PLEASE,
   
   Chad
     _________________________________________________________________
   
   Date: Sun, 09 Nov 1997 00:46:33 -0200 (br> From: Javier Salem
   bbscom@totalnet.com.ar 
   Subject: I need some help
   
   I'm new using Linux but I learn so quicky. I just downloaded
   Communicator for Linux tar version and did all the installation steps,
   but I don't understand how to set the environment variable setenv. I
   think that it's my problem because I can't see Netscape when I open
   xwin, so I can't use it yet
   
   My name is Javier from Argentina. I 'll be pleased if somebody could
   give me a hand. Really thanks.
     _________________________________________________________________
   
   Date: Sat, 08 Nov 1997 09:37:44 -0800
   From: Ted Rolle ted.rolle@usa.net
   Subject: Accessing Win95 vfat drive
   
   I've compiled vfat support into my 2.0.31 kernel. How do I mount the
   drives so Linux can "see" the Win95 partition?
     _________________________________________________________________
   
   Date: Wed, 08 Oct 1997 13:47:17 PDT
   From: "HoonChul Shin" hoonchul@hotmail.com
   Subject: Video woes
   
   Greetings to every Linux lover!
   
   When I run XFree86 ver. 3.2 with resolutions more than 640x340, and
   open menus and move windows around, I see white lines or streaks in my
   screen. It's very annoying. And when I exit Xwindows, and return to
   text mode, screen becomes impossible to read. Fonts just become nasty.
   Is there anyone out there with same problems that I am having now?
   Video Card= Trident TGUI 9682 with 2 mb.
   
   Thanks!
   
   Hoon Chul
     _________________________________________________________________
   
   Date: Tue, 11 Nov 1997 12:51:25 +0200
   From: Ihab Khoury ikhoury@jrol.com
   Subject: NetFlex driver..
   
   Greetings,
   
   I am trying to install RH4.2 on a compaq Proliant 2500. I have a
   NetFlex card built in and unable to read it..I saw that few poeple
   have posted this before ..I was not able to find the driver. Please
   e-mail me at ikhoury@jrol.com if you have any solutions. Thank you in
   advance.
     _________________________________________________________________
   
   Date: Tue, 11 Nov 1997 11:52:48 +0100
   From: Sven Goersmann goersman@student.uni-kassel.de
   Subject: scanner driver or scanner codes for RELISYS Infinty/Scorpio
   VM3550
   
   Hi everybody there!
   
   I just want to ask you if you know there's a Linux scanner driver for
   the RELISYS Scanner Scorpio VM3550 from the Infinity series, and if so
   where can I get it.
   
   Thanks in advance, Sven.
     _________________________________________________________________
   
   Date: Tue, 11 Nov 1997 13:32:34 -0000
   From: Roger Farrell rogerf@icon.co.za
   Subject: Emulators
   
   Hi,
   
   I am looking for emulators that support the 8088 and 80188 chips.
   
   lf you can help please reply.
   
   Regards Roger Farrell
     _________________________________________________________________
   
   Date: Fri, 10 Oct 1997 02:08:44 PDT
   From: Gilberto Persico g_persico@hotmail.com
   Subject: Transaction Processing
   
   Have you ever heard of Transaction Processing systems (such as CICS or
   Encina or Tuxedo) available (free or commercial) for Linux ???
     _________________________________________________________________
   
   Date: Mon, 03 Nov 1997 19:06:53 +0100
   From: Fabrizio fabrizio@euro2001.com
   Subject: chat
   
   HI!
   
   I am looking for a chat program for Unix. Can you send to me some tips
   about this?
   
   Thank you and best regards.
   
   Fabrizio Piccini
     _________________________________________________________________
   
   Date: Sun, 2 Nov 1997 02:04:28 +1100 (EST)
   From: Shao Ying Zhang s2193893@cse.unsw.edu.au
   Subject: Sorry! - RE: SB16 and MIDI
   
   I am sorry for this second mail; I forgot to tell you what the problem
   is. OK, the problem is that it plays without returning any errors, but
   simply no sound comes out.
   
   Thanks very much!
   
   I am using Sound Blaster 16 for my system. My Linux version is Redhat
   4.2 with the kernel 2.0.30.
   
   I recompiled the kernel properly (I think) to make my SB16 work. It
   now can play wave, mod, CD but NOT MIDI.
   
   I can only use timidity to convert them into wave and then play. This
   means that /dev/sequencer does not work properly.
   
   I have also noticed that a couple of other friends have the same
   problem.
   
   Could you help me PLEASE???
   
   Thanks in advance!
   
   Shao Zhang
   2/896 Anzac PDE
   Maroubra 2035
   Australia
     _________________________________________________________________
   
   Date: Wed, 29 Oct 1997 19:51:44 +0900
   From: "Chun, Sung Jin" ninja@aerohel.snu.ac.kr
   Subject: [Q] PCMCIA IBM CD-400 Help me.
   
   I want to access cd-rom using my IBM cd-400 PCMCIA CDROM. But I don't
   know how can I do this. Please help me.
     _________________________________________________________________
   
   Date: Mon, 27 Oct 1997 14:07:47 -0800
   From: "Possanza, Christopher" norvien@halcyon.com
   Subject: HELP! Possible to use parallel port tape drives with linux?
   
   Does anyone know if it's possible to use parallel port tape drives to
   backup a Linux system? I've got the HP Colorado T1000e drive, and I'd
   love to be able to use it... Any suggestions?
   
   Christopher Possanza
     _________________________________________________________________
   
                                General Mail
     _________________________________________________________________
   
   Date: Mon, 06 Oct 1997 18:24:12 GMT
   From: Harry Baecker hbaecker@island.net
   Subject: Word Processing & Text Processing
   
   In his article in Issue 22, subject as above, Larry Ayers indulges in
   the requisite Unixworld denigration of word processor software and its
   users, as contrasted with the virtues of software "which allows the
   writer to focus on content rather than appearance". I suggest that
   there are some errors in this ritual obeisance to received wisdom.
   
   The first is that all who yearn for the services of a word processor
   lust to inflict another Gibbon, "The History of the Decline and Fall
   of the Roman Empire", or Russell & Whitehead "Principia Mathematica"
   upon the world. Were that so then the world would be more than hip
   deep in rejected typescripts already. Rather, I, and I am sure most
   others, wish to prepare snailmail with some attention to personalised
   format and typography, which is exactly what a reasonable word
   processor provides. I certainly do not look for the archetypal offense
   in Ayers' universe of discourse, Microsoft Word for Windows. I have
   borrowed, used, and rejected that, and I have owned, and given away
   AmiPro (WordPro) and abhorred Word Perfect since its inception. What I
   would like to use in Linux is some clone of Wordpad, of MS-Write, or
   of the word processors included with MS-Works or ClarisWorks, wherein
   I can govern not only the content but also the appearance of my
   message.
   
   It is true that Lyx seems to be a reasonable compromise, unless you
   find, as I do, that the assumptions built into its templates are
   displeasing to the eye.
   
   The second error is to assume as gospel the correctness of Unix
   conventions for ASCII text. The ASCII encoding was officially adopted
   by ISO in 1964. That included provision for the CR/LF pair, and a
   functional backspace (not left-erase). Anyone familiar with hardcopy
   terminals of the time, such as Flexowriters, will also remember the
   joys of "line reconstruction" procedures, to encode, say, lines of
   Algol 60 program text, in a useful internal representation. Tortuous,
   but that's what we expect computers to do for us.
   
   The text representation conventions of Unix were born together with
   the limited representational capabilities of video terminals,
   character generators with limited repertoires, no "backspace and
   overtstrike" abilities, hence no way of effecting backspace or CR. By
   the time proper graphic facilities, and hence font choices, became
   available the Unix conventions for ASCII text had ossified, and the
   flexibility actually made available by the original ASCII conventions
   were treated with disdain. Had Unix embraced the full flexibility
   offered by the ASCII encoding then things might have been otherwise.
   
   Harry Baecker
     _________________________________________________________________
   
   Date: Tue, 14 Oct 1997 14:26:20 -0400 (EDT)
   From: Paul Lussier plussier@baynetworks.com
   Subject: Thanks!
   
   Hi,
   
   I've been reading the LG since issue 1 when I first stumbled upon John
   Fisk's web page from an Alta Vista search for Linux info. All of you
   at SSC have done an unbelievably outstanding job with both LJ and LG,
   and I just wanted to say thanks. I look forward to the first week of
   every month when there is a new LG to grab off the net, and a new LJ
   waiting in my mailbox. I read them both cover to cover each and every
   month.
   
   I do Unix sysadmin for a living and still benefit from so much of what
   is originally written with Linux in mind and am able to reuse it on
   other "Unices" as well.
   
   Also, I just checked out CANLUG On-line magazine. It's not bad. Maybe
   you people (and the rest of us too) who have done such a terrific job
   with LG, can give them a hand getting their's off the ground. After
   all, the whole spirit of the Linux community is helping one another :)
   And we can all benefit from another on-line, enjoyable source of Linux
   news and info :)
   
   Thanks again!
   
   Happy Linuxing,
   
   Seeya,
   Paul
     _________________________________________________________________
   
   Date: Fri, 07 Nov 1997 21:05:22 -0800
   From: Andrew T. Young aty@mintaka.sdsu.edu
   Subject: word vs. text processing
   
   While reading Larry Ayres's comments (mostly quite sound) about TeX,
   LOUT, groff, etc., I noticed he was sort of behind the curve on *roff.
   
   First, there are several *good* books on this family of text
   processors. I have troff Typesetting for UNIX Systems by Sandra L.
   Emerson and Karen Paulsell (Prentice-Hall, 1987), as well as UNIX Text
   Processing by Dale Dougherty and Tim O'Reilly (Hayden Books, 1987). In
   addition there is a rather specialized book on the tbl pre-processor
   called something like "setting tables with tbl" -- I don't seem to be
   able to lay hands on it right now. (I might add that I consider tbl to
   be considerably superior to LaTeX's clumsy handling of tabular
   material.)
   
   After you read these books, it's easy to make up a set of formatting
   macros that do for the *roff family exactly what LaTeX does for TeX.
   You can then invoke these very much the way the LaTeX macros are
   invoked; indeed translation from the *roff to the *TeX markup is
   pretty easy at that point (though there are a few subtleties that
   cause problems). LaTeX has a very few advantages for very esoteric
   mathematical equations; apart from that, the systems are very similar.
   
   Yes, the underlying engine is opaque as hell to figure out;
   nevertheless, it's powerful and effective. I still prefer *roff to
   LaTeX, but have been forced to live with *TeX because the journals I
   use all employ it.
   
   One more historical item: Larry called nroff "newer" than troff, but
   it's the other way around. Originally, there was some formatter called
   roff (short for runoff); then came nroff for "new runoff" and then
   *later* came troff for typesetting. -- Andrew T. Young
     _________________________________________________________________
   
   Date: Mon, 3 Nov 1997 09:17:40 -0500
   From: Jack Chaney jac14@chrysler.com
   Subject: new_user_setup
   
   Hi,
   
   I too am a relative newbie (again) to Linux but am sold on a lot of
   the conceptual aspects of the system (shareware, GNU, free downloads,
   world wide support, etc.) I am also quite comfortable with the
   stability and security of the OS. I'm not, however, satisfied with the
   quality of support for new users or "non-experts."
   
   My argument is this, if you are trying to compete in the world market
   with the IBM's and Microsoft's you need to study what it is that made
   them so popular in the first place. Availability of applications,
   which Linux is doing a much better job addressing, is one of the
   pieces that make them so prominent, but it's only one of the pieces.
   The popularity of WIN95 in particular is due to the ease of
   installation of the wanted systems and applications, and the focus on
   the end user.
   
   In the world of computer users the highest percentage of computers are
   set up as single user systems linked to a network, or some central
   server and/or ISP. The majority of documentation material for Linux
   has done an excellent job of describing how to create and maintain the
   system as a central server, but very little copy is devoted to running
   Linux as a client station. Red Hat and others have made great strides
   toward making the install process as painless as possible (my first
   install attempt was back in the 0.98 days). I am able to get most of
   the systems up and running but any time I have questions about a
   particular package, the files it accesses, and where the files reside,
   is always viewed as a fishing expedition.
   
   Also a great deal of software gets installed by the standard install
   process with descriptive text about what the application is during the
   install (I can't read that fast), with a memo at the end of
   installation that a list of what was installed can be found in the log
   directory. When I went to look at the log what I found was a listing
   of the package titles that were installed (little more than the
   filename of the RPM file) and no description about what the package
   does. I found the HOWTO information, but I tend to work better when I
   can read the instructions from hard copy while I work with the
   application on the screen. I could (and do) print out the docs I am
   working with but the expense of this one-of printing is tedious since
   I spent extra money to get the documentation. It is also particularly
   annoying because the documentation has highly detailed chapters on how
   to recompile the kernel (which isn't broken and works just fine) and
   little more than a paragraph making reference to creating a dial-up
   client connection to an ISP (which is what most people want).
   
   I am a computer professional who is quite familiar with OS systems and
   embedded coding and would like to convince management that a
   Linux-based development environment would be a good new direction for
   our teams, but it is a hard sell when the response to on-line queries
   tends to come off as the respondents turning up their nose saying
   "that information is in the docs" and no clue as to which docs or
   where. If the respondents know the answer but are tired of answering
   this question "again" either reprint the old answer, point out where
   the old answer can be looked up, or answer the question "again," not
   blow the person off because the question isn't interesting enough.
   Microsoft and IBM got where they are by taking special interest in
   always answering the "elementary" questions. I realise the nature of
   Linux precludes focusing any resources since it doesn't really have
   any. But if the general Linux public would take a better attitude
   toward people wanting to join up, and lend a helping hand when
   possible, Linux could become a major force in the computer industry.
   
   Jack Chaney
     _________________________________________________________________
   
   Date: Fri, 24 Oct 1997 17:16:04 -0700
   From: Felix Liebau fliebau@metronet.de
   Subject: e mail subscribe?
   
   Hi,
   
   Thanks for that great journal, Linux Gazette, which I really like to
   read. Can I subscribe to have new issues mailed to me?
   
   Felix Liebau
   
     (No, it is impractical to use e-mail to send such large files as
     those that make up LG--1 to 2 MB total for each issue. However,
     check out the Front Page for information about our new notification
     mail list. --Editor)
     _________________________________________________________________
   
   Date: Wed, 12 Nov 1997 23:36:43 +0000
   From: I.P. Robson p.wyrd@netcomuk.co.uk
   Subject: More Praise
   
   You probably get enough of it. But here's more praise. I've just come
   accross this magazine and its the most useful and interesting thing
   I've come across since Linux itself.
   
   Sorry to hear about the November issue but this magazine must be so
   fundamental to everything that isn't Gatesian that you have to keep on
   going.
   
   I wish I had a huge bundle of cash to send you, but you'll have to
   make do with this E-mail instead.
   
   You should have a logo ready to go on every Linux web page everywhere.
   
   I don't often gush with praise and I'd be embarassed if any of my gum
   chewing friends read this. But you deserve it.
   
   I.P. Robson
   --
   The goal of Computer Science is to build something that will last at
   least until we've finished building it.
     _________________________________________________________________
   
             Published in Linux Gazette Issue 23, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Next 
   
      This page written and maintained by the Editor of Linux Gazette,
      gazette@ssc.com
      Copyright © 1997 Specialized Systems Consultants, Inc.
      
    "Linux Gazette...making Linux just a little more fun! "
     _________________________________________________________________
   
                               More 2˘ Tips!
                                      
               Send Linux Tips and Tricks to gazette@ssc.com 
     _________________________________________________________________
   
  Contents:
  
     * Spinning Down Unused HDs
     * Finding What You Want with find
     * Cutting and Pasting Without a Mouse
     * Slow Modem
     * Finding Strings with find
     * Another Calculator Tip
     * Upgrading a Laptop Hard Disk
     * Wallpaper
     * PostScript
     * Linux Virtual Console Key Sequences
     * Netscape Hidden "Easter Eggs"
     _________________________________________________________________
   
  Spinning Down Unused HDs
  
   Date: Sat, 8 Nov 1997 18:34:07 +0100 (MET)
   From: Philipp Braunbeck 100.182763@germany.net
   
   I guess there's no more need to emphasize how much we all like LG.
   Here's just my humble-newbie-one-and-a-half.
   
   If You're like me and You've been upgrading for a couple of years now
   You're likely to have several HD's on Your IDE- or SCSI-Interfaces.
   Now there's probably some GNU-Linux-partition and one or more other
   partitions with M$-stuff on a separate disk. I've got a 120MB Conner
   (with actually nothing on it, I use it as a backup-device; it used to
   be win3.1, but I don't need it anymore :-) which is horribly loud. In
   the old days of DOS one friend of mine wrote a little Pascal-program
   which would stop the disk after a period of time, and it would only
   restart on some (hardware?)-interrupt. Some modern BIOSes can do that
   job for You, but people told me, that either it doesn't work on Linux
   (because the BIOS is only used on bootup in order to get some basic
   configuration) or it is not recommended to do so anyway.
   
   When I was on some adventure-trip through /usr/sbin, I discovered some
   new species called "hdparm", which should be included on any major
   distribution. The manual page says that you can use it to spin down
   any drive on Your system! All You need to do now is putting a line
   like "hdparm -S1 /dev/hdb" in some boot-startup-script (I guess the
   filenames differ in different distributions) and You're done. What a
   silence!
   
   However, You shouldn't do it with Your working /-partition, as it
   syncs the disk every now and then and the disk will keep starting and
   stopping, and this is definitely not good for any HD.
   
   If You like my 2-cent just go ahead and publish it. If not, there will
   certainly be a good reason for this. As I am a newbie, i.e. I've been
   using GNU/Linux for about one year now, I'm humble enough to admit
   that this hint seems more than obvious to any experienced user. But if
   You decide to publish it, I'd prefer that I can stay anonymous, not
   because I got anything to hide, but because I don't want to pretend to
   be someone I'm not, like a sysadmin or I dunno. I've got too much
   respect for them guys who are lots more intelligent than I am, but
   would they ever consider to mail something as primitive as I suggest
   to LG? It really is a matter of getting started for unexperienced
   users, finding that GNU/Linux gets even more powerful while sorting it
   all out. So just put it in "Clueless at the prompt" or where You like.
   Sign with Your name, You knew the trick anyway, didn't You?
     _________________________________________________________________
   
  Finding What You Want with find
  
   Date: Wed, 12 Nov 1997 16:14:43 +0000 (GMT)
   From: Jon Rabone jkr@camcon.co.uk
   
   In the October 97 issue, Dave Nelson suggests using
find . -type f -exec grep "string" /dev/null {} \;

   to persuade grep to print the filenames that it finds the search
   expression in. This starts up a grep for each file, however. A shorter
   and more efficient way of doing it uses backticks:
grep "string" `find . -type f`

   Note however, that if the find matches a large number of files you may
   exceed a command line buffer in the shell and cause it to complain.
     _________________________________________________________________
   
  Cutting and Pasting without a Mouse
  
   From: fk5a005@rrz.uni-hamburg.de
   Date: Wed, 5 Nov 1997 18:58:41 +0100
   
   It is possible, I did think there was no way but there is a way to cut
   and paste without any mouse. Just use screen-3.6x to achieve what you
   may have wanted for a long time. you use screen already but did you
   know how to use this cut-and-paste tool?
     * Use control-a and ESC to switch on Copy-mode.
     * "Drive" thru your screen with j,k and all the other well known
       vi-movements.
     * Mark the area to copy with the space-key.
     * Mark the end of the area with a space-key.
     * Go to another window with e.g. control-a n .
     * Press control-] where you want the pasting to happen. ready!
       
   This was pasting without leaving your keyboard for a while!
   
   Control-a can be any key to achieve a screen-3.6 command. There are
   many more very useful features with screen but i guess that like me
   there are people out there who may not know this very useful feature.
   Another hint: It is really worth printing the Manual. If like me you
   are going by train you can read the Manual x. I found out there are so
   many important features in so many programs I did not know and that
   did help me a lot after discovering.
   
   About vim and completion: there is a feature that lets you complete
   words which you did write before which is very, very useful. press
   control-n in Insert-mode and vim will complete your word if you typed
   it before. It is even better: You can get vim to complete words that
   are in a different file. Just tell vim what the name of the file is
   with :set dictionary=file Then complete the word with
   control-x-control-k. Now imagine how much easier it may be to get a
   list of words with a grep command than to write down all kinds of
   abbreviations and put them into a file. This is a Killer-feature IMO!
   
   About emacs and completion:
   
   Emacs was first with completion or at least this kind of completion
   mentioned for vim goes back to 1992. What you need is hippie-exp.el
   which can perform all kinds of completion.
   
   About atchange
   
   There is a very nice script out there written in perl. I like it very
   much because it lets you perform an action whenever you change the
   date of a file. The action can be almost anything like calling another
   program and executing things or whatever you want. The idea came from
   Tom Schneider who has a page about atchange out there:
   http://www-lmmb.ncifcrf.gov/~toms/atchange.html
   
   I strongly encourage you to read it, this is an idea, that can really
   save your time. The perl-script itself is only 68 lines of code.
   almost one half is explanation, the most important thing is the idea
   itself but Tom has a good page. So I don't tell you more right now :)
     _________________________________________________________________
   
  Slow Modem
  
   Date: Mon, 3 Nov 1997 17:45:13 -0600 (CST)
   From:Michael J. Hammelmjhammel@long.emass.com
   To: Larry E Scheib scheib@tenet.edu
   
   In a previous message, Larry E Scheib says:
   
   When I access a remote site with Linux my screens paint painfully
   slowly; a problem I don't experience with Windows95. When my modem
   connects under Linux it replys "Connected at 38,400", the actual speed
   of my modem. The modem runs off of cua1, IRQ 3.
   
   I'm not very good at debugging modem connections. I've never really
   had any problems with my dial-ups except when the network itself is
   bogged down. To be honest, I have no idea how fast my modem
   connections are actually running. I just know they're tolerable (they
   actually seem to run quite fast - I have a 33.6 modem).
   
   Things that might affect this would be:
    1. some other process sitting on cua0 - perhaps a getty?
    2. You didn't run setserial, a command to setup your serial ports for
       use with modems. I've never run this myself, but I know others
       have had to do so in order to get better throughput. Perhaps its
       because I don't use MS so my ports are not switched back and forth
       between MS and Linux settings.
     _________________________________________________________________
   
  Finding Strings with find
  
   Date: Tue, 28 Oct 1997 16:31:47 +0100
   From: Gordon Walker hellcat@easynet.fr
   
   Being new to Linux I find the Tips section very useful in general and
   the tip about searching for a string with find inspired me to write my
   first conditional Bash script. It finds a string in the current or
   given directory
#!/bin/sh
## Recursively finds all strings in given or current directory
## Usage string_search <dir> <string> (dir is optional)
## For example:          "string_search fish " finds string "fish" in current
directory
##      and             "string_search /water fish " finds string "fish" in dir
ectory
/water
if [ "$2" = "" ]; then
        find . -type f -exec grep "$1" /dev/null {} \;
else
        find $1 -type f -exec grep "$2" /dev/null {} \;
fi
     _________________________________________________________________
   
  Another Calculator Tip
  
   From: Frank Damgaard frank@diku.dk
   Date: Thu, 23 Oct 1997 22:05:14 +0200 (METDST)
   
   In issue 21 there was a smart perl based command line calculator, here
   is another one.
   
   I have for some years used a simple alias for the calculator command.
   The alias only requires awk, and that tcsh (or csh) is the running
   shell. This alias will not work with bash/sh/ksh since these shells do
   not allow arguments in aliases.
   
   Just place the following line in your ~/.tcshrc or type at the prompt:
alias calc 'awk "BEGIN{ print \!* }" '
# When calling calc do not escape "*":
# Example:  calc (3+5)*4/5
     _________________________________________________________________
   
  Upgrading a Laptop Hard Disk
  
   Date: Fri, 24 Oct 1997 14:38:58 -0400
   From: Peter Teuben teuben@astro.umd.edu
   
   I wanted to upgrade the harddisk of my laptop, which had gotten a bit
   tight with 800Mb and maintaining both linux and W95 (don't ask).
   
   I got a new 2Gb drive, and of course wanted to install W95 as well as
   linux. I decided, despite my die-hard Slackware, to try RedHat4.2 for
   linux and basically "copying" W95. Since the laptop is on a local
   ethernet at home, I could make a backup of W95 on the desktop, and
   after linux was braught up, restore W95 back over the network. Indeed
   this worked quite nice, but you have to remember a few tricks. Here
   were my basic steps:
    1. backup, using tar, the old /DOS partition accross the network
    2. replace drive, partitioned as dos on /dev/hda1, swap on hda2, ext2
       on hda3 and hda4. Don't forget to toggle the bootable flags of
       hda1.
    3. installed linux on hda3, and did 'mkdosfs /dev/hda1' to format the
       dos partition from within linux (using DOS bootfloppy and FORMAT
       should work just as well, see my FAT32 caveat below) LILO was
       installed at this stage to boot linux as well as W95.
    4. by default RedHat mounts hda1 as 'dos', but you need to re-mount
       this still empty partition as 'vfat':
umount /DOS
                insmod vfat
        mount -t vfat /dev/hda1 /DOS
    5. untar the previously saved dos.tar back to /DOS, via the network
       from the desktop machine. Since /DOS is vfat, it will properly
       keep the long names.
    6. reboot the machine with a previously made 'emergency W95
       bootfloppy' and run "SYS C:" to restore the bootimage
    7. reboot and select W95 from the LILO prompt, and it should all work
       nicely now (it did for me).
       
   Caveat: For FAT32 versions of W95 (from OSR2 or W98) you may need to
   patch the 2.1.x kernels to include this.
     _________________________________________________________________
   
  Wallpaper
  
   Date: Mon, 27 Oct 1997 14:38:35 +0100
   From: Roger Irwin irwin@mail.com
   
   Use netscape, got xv?
   
   Try running this script in your home directory:
rm -f XVbaa
for foo in .netscape/cache/*
do
for baa in $foo/*.gif
do
echo $baa >>XVbaa
done
done
xv -root -quit -random -flist XVbaa

   This will make you a custom wallpaper on the fly by fishing in
   netscapes cache.
   
   I mapped this to my fvwm2 button bar by using the following lines in
   .fvwm2rc95:
*FvwmButtons(Title Mood, Icon exit.xpm, \
       Action 'Exec XVchange ')

   This goes in the FVWM buttons section in the middle of the other lines
   that define the other buttons.... When I hit the Mood button, the
   wallpaper changes. I suppose a lazier person might use crontab....
     _________________________________________________________________
   
  PostScript
  
   Date: Sun, 9 Nov 1997 22:00:31 +0000 (GMT)
   From: Ivan Griffin ivan.griffin@ul.ie
   
   Counting the Number of Pages in a file
   
   To count the number of pages in a PostScript file, you are relying on
   the creator of the file to have been a sociable application and to
   have followed the Adobe Document Structuring Conventions (ADSC). These
   conventions entail the automatic placement of comments (%%) in the
   PostScript source so that additional applications will find it easier
   (and indeed, possible!) to post-process the PostScript without having
   to interpret it. They are generally ignored by PostScript interpreters
   and printers. The comment '%%Page:' delimits each new page. So to
   count the number of pages in a DSC compliant PostScript file, all you
   have to do is grep for the number of '%%Page:' markers:
grep -c '%%Page:' filename.ps

   I generally tend to alias this to pspage in my .cshrc
alias pspage 'grep -c %%Page:'

   Printing 2up
   
   The utility pstops, part of the psutils package, allows you to process
   a PostScript file to enable 2up printing. I find the following works
   for A4 (European) paper -- the measurements will need to be tweaked
   for US Letter:
alias psdouble 'pstops "2:0L@.7(21cm,0)+1L@.7(21cm,14.85cm)"'

   To use it, it is as simple as:
psdouble < 1up.ps > 2up.ps

   Microsoft Ugly PostScript
   
   Quite often in PostScript generated by the Microsoft Windows driver,
   it requires the interpreter to have 30MB of memory, and refuses to
   print otherwise!! This is quite incredible, and I have found that it
   always seems to print perfectly well if this artifical limit is
   removed. The PostScript in question is:
   
   /VM? {vmstatus exch sub exch pop gt { [ (This job requires more memory
   than is available in this printer.) 100 500 (Try one or more of the
   following, and then print again:) 100 485 (In the PostScript dialog
   box, click Optimize For Portability.) 115 470 (In the Device Options
   dialog box, make sure the Available Printer Memory is accurate.) 115
   455 (Reduce the number of fonts in the document.) 115 440 (Print the
   document in parts.) 115 425 12 /Times-Roman showpage (%%[
   PrinterError: Low Printer VM ]%%) = true FatalErrorIf}if} bind def
   30000 VM?
   
   The line "30000 VM?" checks that (roughly) 30MB of memory is available
   in the printer. Deleting this line is sufficient to ensure that the
   check is not performed, and that the job will now print (or be
   interpreted successfully in ghostview for example).
     _________________________________________________________________
   
  Linux Virtual Console Key Sequences
  
   Date: Sun, 9 Nov 1997 22:00:31 +0000 (GMT)
   From: Ivan Griffin ivan.griffin@ul.ie
   
   Pressing these key sequences on a VC will dump information to the
   screen.
   
   Displaying task information:
   
   Ctrl-Scroll Lock gives:
             free            sibling
 task       PC  stack  pid father child younger older
swapper  0 R current  4096   0   0   1
init    1 S FFFFFFFF 2676   1   0  706
kflushd  2 S 00000000 3984   2   1       3
kswapd   3 S 00000000 3976   3   1       4   2
nfsiod   4 S 00000000 3520   4   1       5   3
nfsiod   5 S 00000000 3520   5   1       6   4
nfsiod   6 S 00000000 3520   6   1       7   5
nfsiod   7 S 00000000 3520   7   1      21   6
bash    8 S 00000000 3012  172  164  711
login   9 S 00000000 2820  164   1  172   166  135
kerneld  10 S 00000000 3224  21   1      76   7
login   11 S 00000000 3012  706   1  712      571
syslogd  12 S FFFFFFFF 3192  76   1      85  21
klogd   13 R 00000000 3404  85   1      96  76
crond   14 S 00000000 3480  96   1      108  85
inetd   15 S FFFFFFFF 3464  108   1      119  96
lpd    16 S FFFFFFFF 3376  119   1      135  108
gpm    17 S 000B206C 3368  135   1      164  119
vi    18 S FFFFFFFF 3012  711  172
mingetty 19 S FFFFFFFF 3012  166   1      167  164
bash   20 S 00000000 3012  712  706  724
httpd   21 S 00000000 3460  573  571      574
httpd   22 S 00000000 3600  574  571      575  573
httpd   23 S 00000000 3308  571   1  579   706  171
httpd   24 S 00000000 3600  575  571      576  574
mingetty 25 S FFFFFFFF 3012  167   1      168  166
mingetty 26 S FFFFFFFF 3012  168   1      169  167
mingetty 27 S FFFFFFFF 3012  169   1      171  168
httpd   28 S 00000000 3600  576  571      577  575
update  29 S 00000000 3460  171   1      571  169
httpd   30 S 00000000 3600  577  571      579  576
vi    31 S FFFFFFFF 3012  724  712
httpd   32 S 00000000 3600  579  571         577

   Displaying Memory Information
   
   Shift-Scroll Lock gives:
Mem-info:
Free pages:    3136kB
 ( 4*4kB 0*8kB 1*16kB 1*32kB 0*64kB 24*128kB = 3136kB)
Swap cache: add 0/0, delete 231912/0, find 0/0
Free swap:    16596kB
5120 pages of RAM
789 free pages
449 reserved pages
2572 pages shared
Buffer memory:   2324kB
Buffer heads:   2340
Buffer blocks:   2324
Buffer[0] mem: 1953 buffers, 10 used (last=1953), 0 locked, 0 protected, 0 dirt
y 0 shrd
Buffer[2] mem: 337 buffers, 25 used (last=337), 0 locked, 0 protected, 0 dirty
0 shrd
Buffer[4] mem: 3 buffers, 3 used (last=3), 0 locked, 0 protected, 3 dirty 0 shr
dSize  [LAV]   Free Clean Unshar   Lck  Lck1  Dirty Shared
 512 [  0]:    0    0    0    0    0    0    0
 1024 [ 186]:   31  1953    0   337    0    3    0
 2048 [  0]:    0    0    0    0    0    0    0
 4096 [  0]:    0    0    0    0    0    0    0
 8192 [  0]:    0    0    0    0    0    0
0
     _________________________________________________________________
   
  Netscape Hidden "Easter Eggs"
  
   Date: Sun, 9 Nov 1997 22:00:31 +0000 (GMT)
   From: Ivan Griffin ivan.griffin@ul.ie
   
   These special URLs do interesting things in Netscape Navigator and
   Communicator.
about:cache gives details on your cache
about:global gives details about global history
about:memory-cache
about:image-cache
about:document
about:hype
about:plugins
about:editfilenew

view-source:URL opens source window of the URL

   Ctrl-Alt-F take you to an interesting site :-)
     _________________________________________________________________
   
             Published in Linux Gazette Issue 23, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next 
     _________________________________________________________________
   
      This page maintained by the Editor of Linux Gazette, gazette@ssc.com
      Copyright © 1997 Specialized Systems Consultants, Inc.
      
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                                 News Bytes
                                      
                                 Contents:
                                      
     * News in General
     * Software Announcements
     _________________________________________________________________
   
                              News in General
     _________________________________________________________________
   
  New URL for LG
  
   Linux Gazette now has its own domain name! Check out
   http://www.linuxgazette.com/ as another way to get to LG.
   
   Other LG News While we do not mail issues of LG to our readers--it's
   just too big--we do have an announcement service. Write
   lg-announce-request@ssc.com with the wordsubscribe in the body, and
   each month you will receive an e-mail notice when we post Linux
   Gazette.
   
   Our ftp site will now contain each issue after Issue 9 in its own
   gzipped tar file. Issues 1 through 8 will be together in one gzipped
   tar file.
     _________________________________________________________________
   
  Cool Linux Sites of December!
  
   Check out the two cool Linux sites of the month!
   
   The Rat Pack Underground Network is a must-see. This URL has some
   practical stories about using Linux to solve "real-life" problems and
   much more.
   
   The Eyes on the Skies Robotic Solar Obsevatory and BBS page contains
   an internet-accessable robotic solar telescope and BBS system built by
   Mike Rushford. You can actually control your view of the sun by
   controlling a telescope from your browser! The telescope control pages
   are served by a Linux system that is called Eyes on the Skies.
     _________________________________________________________________
   
  Stand Up and Be Counted
  
   The Linux Counter is a serious attempt to count users in the Linux
   universe. At the moment, more than 53.000 people are registered with
   the counter, coming from more than 130 different countries. The
   counter has been recently updated and given a new Web interface and
   forms design, and is now able to give you the ultimate Linux counter
   gimmick: The Linux REGISTRATION CERTIFICATE! This little GIF image,
   with your personal registration number on it, ready for insertion in
   your Web page, is available for you at the price of filling out the
   registration form. Older, registered users can go to
   http://counter.li.org/update.html, enter their registration key, and
   get it there.
   
   Come on folks--STAND UP AND BE COUNTED!!!!
     _________________________________________________________________
   
  Virtual Services HOWTO
  
   Check out the new HOWTO on virtual services which includes a section
   on virtual mail services as a whole. Go to
   http://sunsite.unc.edu/mdw/HOWTO/Virtual-Services-HOWTO.html The
   author would like your comments on the HOWTO in order to keep it on
   track, you can reach him at brian@nycrc.net
     _________________________________________________________________
   
                           Software Announcements
     _________________________________________________________________
   
  Eiffel Special
  
   In celebration of the 200,000th Eiffel Professional license, ISE is
   making available special limited time offers for new purchases of the
   Eiffel Professional Licence and upgrades from Personal Eiffel.
   
   FREE Upgrade to Eiffel Professional license with NEW Java Interface
   (see offer for full details)
   
   Eiffel Professional Suite $495
     * EiffelBench
     * EiffelBase
     * EiffelLex
     * EiffelParse
     * EiffelVision
       
   Eiffel Client-Server Suite $795
     * EiffelBench
     * EiffelBase
     * EiffelLex
     * EiffelParse
     * EiffelVision
     * EiffelWeb
     * EiffelNet
       
   Eiffel Cross-Platform Suite $895
     * EiffelBench
     * EiffelBase
     * EiffelLex
     * EiffelParse
     * EiffelVision
     * EiffelWeb
     * MEL
       
   Eiffel Enterprise Suite $1195
     * EiffelBench
     * EiffelBase
     * EiffelLex
     * EiffelParse
     * EiffelVision
     * EiffelWeb
     * EiffelNet
     * MEL
     * EiffelCase
       
   A special bonus runs with each of the above which includes a free
   upgrade to the next release, a free O-O book and 15% off any ISE
   training session up to June 1998. The Enterprise Suite also includes a
   free year of maintenance and support from the date of purchase.
     _________________________________________________________________
   
  O'Reilly "Animal Book" Contest
  
   Readers of the "Animal Books" by O'Reilly now have a chance to see
   some wild animals close up, courtesy of computer book publisher
   O'Reilly & Associates. O'Reilly has launched the In a Nutshell
   contest, with the prize being a trip for two to the San Diego Zoo and
   Wild Animal Park. Readers of O'Reilly's bestselling In a Nutshell
   quick-reference books can find entry forms at their favorite
   bookstores. Completed entry forms must be received by December 31,
   1997, and the winner will be chosen on January 30, 1998.
   
   Official In a Nutshell Contest Rules:
     * Completed entry forms must be received by December 31, 1997, in
       order to qualify.
     * No purchase necessary to enter. (However, please include original
       cash register receipt or a legible copy if purchase is made.)
     * Offer good in USA and Canada.
     * Not responsible for lost, late, misdirected, or illegible entry
       forms.
     * Void where prohibited, taxed, or restricted by law.
     _________________________________________________________________
   
  Help with JWP
  
   There is a Windows application, called JWP -- a Japanese Word
   Processor. This package was written by Stephen Chung, and as a GNU
   product it is freely distributable. JWP comes with its own fonts and
   its own Front End Processor (FEP) which means it is useful on
   English-only computing systems. It is also integrated with Jim Breen's
   EDICT Japanese-English dictionary. Unfortunately, JWP is only
   available for Windows right now, which is locking out a lot of people
   under other platforms who might benefit from it. As Stephen is quite
   busy with full-time work and maintaining the Windows versions (he's
   developing version 2.00 now), there is an attempt being made to go
   ahead and port to X-Windows.
   
   This project will never get off the ground without volunteers. any
   interested X-Windows developer who wants to make a contribution both
   to the GNU and Japanese-speaking communities is invited lend a hand
   with this exciting project.
   
   The JWP-Port Project home page contains more information on the JWP
   package as well as the JWP-Port project itself. If you are interested,
   please visit the page at http://qlink.qheensu.ca/~3srf/jwp-port.
     _________________________________________________________________
   
  Perfect Backup+ Personal Edition
  
   Unisource Systems, Inc. announced today the release of the famous
   PerfectBACKUP+ Personal Edition, a fully functional version of their
   best-selling PerfectBACKUP+ V5.5. Having received continued and
   tremendous support from the LINUX community, and in recognition of
   LINUX becoming our #1 best-selling platform we are giving something
   back. The PerfectBACKUP+ Personal Edition is unrestricted and free to
   anyone. Its freely redistributable and can be use for either private
   or commercial use.
   
   Information about, and the program itself can be obtained from
   http://www.unisrc.com.
     _________________________________________________________________
   
  86Open Project
  
   A group which includes some of the key developers of Unix operating
   systems on Intel architecture computers have agreed to work on a
   common programming and binary interface. At a meeting held mid-August
   at the head office of SCO, participants achieved consensus on a way to
   create software applications which would run, without modification or
   emulation, on the Intel-based versions of:
     * BSDI
     * FreeBSD
     * Linux
     * NetBSD
     * SCO OpenServer
     * Sunsoft SolarisX86
     * SCO UnixWare
       
   The goal of this effort is to encourage software developers to port to
   the Unix-Intel platform by reducing the effort needed to support the
   diverse mix of operating systems of this kind currently available. The
   specification, called "86open", will be published and freely available
   to any environment wishing compliance. It involves the use of a
   standardized 'libc' shared library of basic functions to be provided
   on all systems. This library will provide a consistent interface to
   programmers, hiding the differences between the various operating
   systems and allowing the resulting binary programs to run unaltered on
   any compliant system. Whenever possible, it will be consistent with
   The Open Group's Single Unix Specification.
   
   Each participating operating system will be free to implement the
   86open library specification on its own. However, the reference
   implementation will be based upon GNU's 'glibc' version 2, ensuring
   that it will remain open and freely available. The actual list and
   behavior of the 86open functions is presently being determined.
   
   Participants in the meeting, who will be involved with the ongoing
   evolution of the 86open specification, include people deeply involved
   with the operating systems mentioned in this project. The 86open
   steering committee, a core of this group which will assemble the work
   and produce the final specification, comprises: Marc Ewing, Dion
   Johnson, Evan Leibovitch, Bruce Perens, Andrew Roach, Bryan Sparks and
   Linus Torvalds
   
   For more information, contact 86open@telly.org or check
   http://www.telly.org/86open.
     _________________________________________________________________
   
  Clobberd 3.2
  
   Clobberd 3.2 (Clobberd-3.2-RELEASED.tgz) has been released on to the
   following sites:
     * ftp://ftp.funet.fi/pub/linux/incoming
     * ftp://sunsite.unc.edu/incoming/Linux
     * http://dayworld.net.au/~jsno/rel/1997
       
   Clobberd is a user/resource regulator that allows Operators to monitor
   and track users Total Time, Daily Time, Expiration time, Total network
   usage and Daily network usage (to name a few) in an effort to limit or
   cost resources that the user uses. Clobberd effectively "meters"
   resources, and compares them to any limits/conditions you impose. The
   third version now has the ability to monitor users on a network rather
   than a single host.
     _________________________________________________________________
   
  Corel Video Network Computer News
  
   When Corel Computer Corp. formally unveils its Video Network Computer
   later this month, the machine will be running Linux, an operating
   system that is becoming an increasingly prominent force in
   workstations linked to corporate intranets.
   
   Linux is a compact, efficient, easier-to-use and free version of Unix.
   A growing number of corporate MIS groups, as well as software
   developers and systems integrators, are choosing Linux over 32-bit
   Windows platforms, especially for Internet applications. At some
   sites, Linux actually is displacing Windows.
   
   That is what happened at Unique Systems, Inc., a software developer in
   Sylvania, Ohio. The company, which puts together accounting systems
   for small and midsize companies, was using Microsoft Corp.'s Office 95
   internally but was plagued by software crashes and other problems. "It
   really irked me," Unique President Glenn Jackson said.
   
   The company tested Applix, Inc.'s ApplixWare office suite on Intel
   Corp. computers running Linux. Users got nearly all the functionality
   of Microsoft Office and were able to import all Office files easily
   into ApplixWare - at much lower cost and with far greater reliability
   than with Office, Jackson said.
   
   "Linux is the true competitor to Windows NT in the long term," said
   Dave Madden, senior product manager at Corel Computer, a subsidiary of
   Corel Corp., based here.
   
   Linux has a number of key features NT lacks. For example, Linux is a
   multiuser system and runs on a wide range of processors _ from Intel
   386 to 64-bit Reduced Instruction Set Computing chips _ and on
   multiprocessor computers. The Linux kernel is less than 2M bytes.
   
   Linux has other key attractions, according to Jon Hall, executive
   director of Linux International, a trade group that promotes the
   software. Linux is free, and users have access to all the Linux source
   code, which means they can make whatever changes they need. Commercial
   Linux versions from companies such as Caldera, Inc., of Provo, Utah,
   and Red Hat Software, Inc., of Research Triangle Park, N.C., range
   from $49.95 to $399 and usually come with additional software and
   technical support.
   
   The free version of Linux is crammed with utilities and connectivity
   software. "One of the things that makes Linux so attractive is how
   much software you get with it," said Dave Parker, a senior software
   engineer at Frontier Information Technologies, a division of Frontier
   Corp., a Rochester, N.Y., telecommunications company. "Linux will
   connect to anything."
   
   Much of the free software is available under the "GNU public license,"
   which is administered by the Free Software Foundation.
   
   For example, TCP/IP and a Web server are built in, and Linux can run
   DOS applications. It includes X.11 support, so it can host or access
   Unix applications.
   
   Linux supports the Microsoft Server Message Block protocol, so it can
   serve Windows files.
   
   It also supports AppleTalk for Macintoshes. Using optional software,
   it can even run Windows applications. Cal-dera's commercial OpenLinux
   adds Novell, Inc. NetWare connectivity.
   
   Frontier Information Technologies' Green Bay, Wis., site is using
   several Caldera Open- Linux servers as specialized gateways, directory
   or naming servers and firewalls.
   
   This seems to be an increasingly common practice at big corporate
   sites, said Dan Kusnetzky, director of operating system research at
   International Data Corp. in Framingham, Mass.
   
   Unknown to senior MIS executives, operations staff are deploying Linux
   servers in a range of intranet applications, he said.
     _________________________________________________________________
   
             Published in Linux Gazette Issue 23, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next 
     _________________________________________________________________
   
      This page written and maintained by the Editor of Linux Gazette,
      gazette@ssc.com
      Copyright © 1997 Specialized Systems Consultants, Inc.
      
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                               The Answer Guy
                                      
                   By James T. Dennis, answerguy@ssc.com
          Starshine Technical Services, http://www.starshine.org/
     _________________________________________________________________
   
  Contents:
  
     * Running Multiple Instances of X
     * VC Madness
     * Linux and OSPF
     * Security Problems with pop3
     * Cryptographic System
     * An Interesting De-Referencing Problem
     * Reminder!
     * pcmcia ide Drives
     * KDE BETA 1
     * Compression Program
     * loadlin
     * WipeOut
     _________________________________________________________________
   
  Running Multiple Instances of X on One Video/Monitor (VCs)
  
   From: Guillermo S. Romero famrom@ran.es
   
   Hello,
   I have tried to run multiple X servers with only one card and one
   monitor. Is this possible, or is it normal that the second X server
   does not run? I used startx display :0 the first time, and :1 the
   second. I have a 1024K video board (#9GXE64 PCI, S3 864), and normal
   config is 8 bpp, 1024*768 virtual desktop, running on a remix of
   RedHat 4.0, 4.1 and 4.2, with XFree86 as server. Maybe I did not
   understand the man page (English is not my first languaje). Any
   suggestion? 
   
   The normal way this is done is using the form:
        startx -- :0 &
                startx -- :1 &

   ... The -- is used by startx and xinit to separate an optional set of
   client parameters from the set of display/server options and
   parameters.
   
   If you ran the command:
        startx xterm -e myprog -- :1 &

   ... it would start X Windows with a copy of xterm which would be
   running 'myprog' (whatever that might be). The remainder of the line
   informs the X server to use display number one (which would be VC --
   virtual console -- number eight on most Linux systems).
   
   (On my systems it would start on VC#14 -- accessed with the {Right
   Alt}+{F2} key combination. I routinely configure mine with 24 VC's --
   the first twelve of which have "getty's" (login prompts) and the next
   eleven of which are available for X (xdm's or otherwise), using 'open'
   commands, or for dumping status output from a process (like 'make' or
   'tail -f').
   
   Read the man pages for startx and xinit one more time. I'm pretty sure
   that the man pages have all been translated into Spanish -- so you
   might want to hunt those down.
   
   Thanks!!! 
   
   Read the man pages for startx and xinit one more time.
   
   Sure, and with a dictonary. ;] 
   
   I'm pretty sure that the man pages have all been translated into
   Spanish -- so you might want to hunt those down.
   
   Try:
   
   man-pages-es-0.2-1.src.rpm:
   ftp://ftp.redhat.com/pub/contrib/SRPMS/man-pages-es-0.2-1.src.rpm
   
   The Spanish Howto is small, too global, sure it does not cover that.
   And I still have problems with my ntilde chars and acents, Spanish is
   not supported a lot (Linux or another OS, always late and bad)... The
   system explained in that howto does not work (but thats another
   question, whose solution maybe... magic? real support?). GSR 
   
   I'm afraid I'm completely ignorant of internationalization issues with
   Linux. I do know that there is quite a bit of work done on Linux boxes
   in Japan, Germany, Italy and, naturally enough, Finland (where Linus
   comes from).
   
   As bad as it seems -- Linux' support for other languages is probably
   the best in the world. Unfortunately I don't have the skill or
   resources to point you to the support and resources you need.
   
   Since your English is clearly adequate to discuss these issues with me
   -- you might consider contributing some of your time to a translation
   effort (get the LIGS, NAG, and SAG portions of the Linux Documentation
   project translated, and "beef up" (improve) the Spanish-HOWTO.
   
   I highly recommend that you find or start a Linux user's group in your
   area. This is the best way to help yourself and to improve the
   situation for all of your compatriots.
   
   -- Jim
     _________________________________________________________________
   
  VC Madness
  
   From: frees@technologist.com
   
   Hi
   I have an application that uses its own .cshrc and .bashrc to fire up
   and this is done by using its own login account. Now what I would
   really like is for this to say select VC8 to run on and then have my
   normal X on VC7 as usual. Can this be done? and if so how?
   --Phil 
   
        open -c 8 -- su - $PSUEDOUSER

   ... where PSUEDOUSER is the psuedo users whose .*shrc you want to run.
   Naturally you can convert the .*shrc into a normal shell script and do
   whatever you like with it. You have to run this as root -- (so 'su'
   doesn't prompt for a password) though there are ways to get around
   that 'runas' is available at the sunsite.unc.edu archive site and its
   mirrors). If launch this from another UID you'll need to ensure that
   this users (the launching user, not necessarily the psuedo-user) has
   write access to /dev/tty8 (group +w should be sufficient).
   
   If you want to have the console visually switch to this application's
   VC you can just add the -s switch like so:
        open -c 8 -s -- ....

   ... where the "--" marks the end of 'open's' arguments so that the
   command that follows it can unambigously get its own arguments.
   
   Without the -c switch the 'open' command will select the next
   available VC. Any subsequent 'startx' commands or other 'open'
   commands would then pick later ones (unless the others were freed back
   up).
   
   You can have two or more copies of X running on different VC's as
   well. For example the command:
        startx -- :1

   ... will create a second X session on the localhost:1 display (the
   first one is addressed as localhost:0 or simply :0). These X sessions
   can be run under different UID's and have completely different client
   configurations (colors, window managers, etc). There is also an
   'Xnest' command that works similarly -- allowing one X session to run
   "within" (as through a window on) one of your existing X sessions.
   
   You can also set the terminal settings and colors using normal
   redirection of the form:
stty erase ^? > /dev/tty8

   ... and:
setterm -background blue -foreground yellow -bold on -store \
                > /dev/tty8

   This last command would set and store a new set of default screen
   colors for the VC. The setterm command can also be used to control the
   Linux VC screen blanker's timeout (a value of 0 means "never blank").
   
   Naturally you may want to read the man pages for all of these.
   
   If you want to ensure that a given process will *always* be running
   (and will automatically be respawned when it dies) you can add it to
   your /etc/inittab -- so that the init process will watch over it. This
   is how new 'getty' processes are spawned on your first six (or so)
   VC's when you boot and are respawned when you logout. Likewise if you
   use 'xdm' to keep a graphical (X based) login prompt on one or more of
   your VC's.
   
   As you can see, its possible to do quite a bit with Linux VC's. I run
   12 VC's with getty (as login consoles), have one 'xdm', one devoted to
   syslog, and ten more available for other purposes (such as 'startx'
   and 'open' commands and to to use for 'tail -f' commands when need to
   monitor the end of a status or log file -- from a 'make' or whatever.
   
   The second set of 12 VC's is accessed with the *right* {Alt} key. (In
   case you'd never noticed, the default keyboard settings of Linux only
   allow you to use the *left* {Alt} key for switching VC's). I set
   syslog to use VC number 24 with an entry in the /etc/syslog.conf file
   that reads:
        *.*                     /dev/tty24

   This puts a copy of *every* syslog message on to that VC -- which is
   what I switch to for a quick glance and try to switch to when I leave
   any of my systems unattended. (That way when one does lock -- as rare
   as that is -- I have some idea of what the last throes of the system
   were).
   
   I set that to bright red on black with the following command in my
   rc.local file:
setterm -foreground red -bold on -store > /dev/tty24

   (I also do the same to /dev/tty12 which I customarily use only for
   root login's).
   
   Hope all of that helps.
   
   -- Jim
     _________________________________________________________________
   
  Linux and OSPF
  
   From: Jose Manuel Cordova-Villanueva jcordova@amoxcalli.leon.uia.mx 
   
   Dear Sr.
   Recenty I had my first contact with the Linux G. and is a big source
   of information, can you inform me if there are a program that can talk
   ospf because our ISP, is changing from RIP to OSPF and we have a linux
   box in one of our links, for our cisco no problem but for our Linux
   box?? 
   
   The software you want is called 'gated' (for "gateway daemon"). This
   is a Unix multi-protocol router package for Linux which includes
   support for OSPF and other routing protocols (BGP4, IGRP, etc).
   
   Here's a link to the top level 'gated' pages Cornell Gated Consortium
   Information
   
   I've heard that compiling 'gated' for Linux is not quite trivial so
   here is some other links that might help: Here's a link to a source
   RPM in the Red Hat contrib directory: gated-R3_6Alpha_2-1.src.rpm
   
   Here's a threaded archive of the 'gated' users mailing list:
   Gated-People Archive Here's an odd note about an alternative routing
   software package/project: Route Servers -- RA.net: routing arbiter
   project
   
   Hope that helps.
   
   -- Jim
     _________________________________________________________________
   
  Security Problems with pop3 of Linux 2.1.29
  
   From: Sam Hillman hillman@easyway.net
   
   Well I hope I'm posting to the right person. I have two questions,
   which I hope you can answer. 1. How do I setup my linux machine as a
   POP3 server? I can't find any FAQs or Howtos. 
   
   Usually you don't have to do anything extra to allow access to POP
   services. Most Linux distributions include a pop server pre-installed
   and appearing in the /etc/inetd.conf and /etc/services files.
   
   A quick test is to login to the system in question and type the
   command:
telnet localhost pop-3

   ... it should respond with something like:
+OK your.hostname .... (some copyright info)

   ... and you can type QUIT to get out of that.
   
   If that doesn't work you'll want to make sure that the appropriate
   lines appear in your /etc/services and /etc/inetd.conf files like so:

/etc/services:
pop-3           110/tcp # PostOffice V.3
pop             110/tcp # PostOffice V.3

/etc/inetd.conf:
pop-3   stream  tcp     nowait  root    /usr/sbin/tcpd  ipop3d

   If they appear commented out -- remove the leading hash sign(s) (or
   paste these samples in) and restart your inetd with a command like:
kill -HUP `cat /var/run/inetd.pid`

   2. When I log on to my ISP, I download my mail and it gets dumped to
   the sendmail, this creates a situation where the mail is bounced back
   and forth until it passes the hop limit and is dumped as an error
   message in the postmaster box, and a nasty letter is send to the
   originator from MAILER-DEMON... I think this maybe because I'm running
   a local area network between my two machines, the IP address of the
   local net is 162.blah.blah... But I also have the IP address the ISP
   gave me in the host file. If the ISP's IP address is the problem can I
   remove it from the host file, and just get a duynamic IP when I
   connect? Thanks in advance! 
   
   This is a bigger problem. First the 162.*.*.* is probably not what you
   want to use for you disconnected LAN. There is an RFC 1918 (originally
   RFC 1597) which describes and reserves a set of addresses for
   "non-Internet" use. These are guaranteed not to collide with any valid
   (routable) hosts on the 'net. Here's the list of those addresses:
        192.168.*.*  (255 class C address blocks)
                172.16.*.* through 172.31.*.* (15 class B address blocks)
                10.*.*.*  (one class A address block)

   ... use those however you like. Be sure to keep them behind your own
   routers (make any hosts with those go through an IP masquerading or
   NAT -- network address translation -- router, or through a SOCKS or
   other proxy server).
   
   The next problem is configuring sendmail for use on a disconnected
   system. You probably need to define your hostname (or an alias to your
   hostname) to match what your ISP has named you. Each ISP seems to use
   a different way to manage these "disconnected sendmail subdomains" --
   with no standardization in site (which is why I use UUCP). I gather
   that some people use a scheme where they only run sendmail when they
   are connected. The rest of the time their MUA (mail user agents like
   elm, pine, mh-e, exmh, etc) just drop outgoing mail into the mqueue
   directory where 'sendmail' will get to it later. One problem I have
   with these configurations is that sendmail wants to look up these
   remote hosts. This seems to cause various problems for users of
   "disconnected" or "periodically connected" (dial-up) systems. So far
   the only solutions I've found are: recompile sendmail without DNS
   support (there used to be a sendmail.cf switch that disabled DNS and
   reverse DNS activity in sendmail -- but that doesn't seem to work any
   more) use UUCP. UUCP was designed for disconnected (dial-up) and
   polling systems. It's what I use. The disadvantage to UUCP is that
   it's a bit hard to set up the first time -- and you have to find a
   provider that's willing to be your MX/SMTP to UUCP gateway. There are
   still some people out there where will do this for free or at only a
   nominal fee. But they are increasingly hard to find. I use a2i
   Communications in San Jose. You could use a non-local provider if you
   want to use UUCP over TCP as the transport mechanism (UUCP is pretty
   flexible about the underlying transports -- you could probably use tin
   cans and string as far as its concerned).
   
   There are several HOWTO's that try to cover this topic. Try browsing
   through some of these:
     * ISP Hookup HOWTO: Basic introduction to hooking up to an ISP.
     * Electronic Mail HOWTO: Information on Linux-based mail servers and
       clients.
     * Mail Queue mini-HOWTO: How to queue remote mail and deliver local
       mail.
     * Offline Mailing mini-HOWTO: How to set up email addresses without
       a dedicated Internet connection.
     * UUCP HOWTO: Information on UUCP software for Linux.
     * Sendmail+UUCP mini-HOWTO: How to use sendmail and UUCP together.
       
   -- Jim
   
   Thanks so much for the detailed suggestions. We have installed a newer
   version of pop3 on our server for now and we will look into the
   feasibility of implementing some of your suggestions for a final cure.
   Thanks again, James, we really appreciate it.
   -Sam Hillman, Service Manager, Easyway Communications. 
     _________________________________________________________________
   
  Cryptographic System
  
   From:Emil Laurentiu emil@interlog.com 
   
   Hello Jim, 
   
   Sorry for bothering you but I would apreciate a lot an answer even a
   short one like 'no' :) I am (desperately) searching a crypographic
   system for my Linux box. I am already using TCFS but I'm not very
   happy with it for several reasons: it is slow, I experienced some data
   loss, must use the login password, cannot share encypted files with
   other users, NFS - increses security riscs. And the people in Italy
   seemed to have stoped work on this project (latest version is dated
   february). 
   
   February doesn't seem that old.
   
   Are you sure you're using the latest TCFS (v 2.0.1)? You can find that
   at: http://pegaso.globenet.it (which is a web form leading to an HTTPS
   page -- so use and SSL capable browser to get there).
   
   If you find it slow than any other decent encryption is also likely to
   be too slow for you.
   
   You could look at http://www.replay.com (in the Netherlands). This has
   the best collection of cryptography software I've seen anywhere.
   
   The two fs level alternatives to TCFS are CFS (Matt Blaze's work, on
   which TCFS was based) and userfs (which support a few different
   user-level filesystem types including an experimental cryptographic
   one.
   
   I am wondering if you know anything about an encryption at the file
   system level. Something like SecureDrive (from DOS :) which did IDEA
   encryption on the fly at sector level for a partition and was very
   fast. 
   
   Are you sure SecureDrive is using IDEA? I rather doubt that.
   
   As an (almost) single user on my linux machine something like this
   would be more apropriate. Of course if I would not find one I'll
   finish by writing it by myself. My only concern is that I've been a
   Linux user only for half a year and I did not get the chance to study
   the kernel to well (this will be a good opportunity :) 
   
   Why not pick up on the TCFS or CFS work? Why not build on the userfs
   work (plugging in whatever encryption you like)?
   
   Why write it "by yourself" when you can collaborate with other members
   of the Linux community as they have done to bring you Linux itself,
   and as the FSF and others have done to bring you the GNU packages
   which turn Linux into a full OS?
   
   What you asking for doesn't need any support at the kernel level.
   userfs and CFS already have shown that. The Linux kernel already
   support a robust and open filesystems interface (which support more
   different filesystem types than any other -- with read-only support
   for HPFS, NTFS, BSD and Sun UFS/FFS, and support for HFS (Mac),
   ext2fs, xiafs, Minix, and many others.
   
   If you're a competant programmer (which I am not, BTW) you should be
   able to trivially take the sources for any of the existing filesystem
   modules and hack together your own with the encryption support of your
   choice. How secure the result will be will be a matter of your skills
   -- and should be greatly improved by peer review (by publishing your
   work for all to see).
   
   Naturally if you are in a free country you can share your work on
   cryptography with the world. However the USA doesn't appear to
   currently be free in this particular respect -- please find a congress
   critter to vote out of office if this oppresses you.
   
   -- Jim
     _________________________________________________________________
   
  An Interesting De-Referencing Problem
  
   From: Kevbo simitar@lvnworth.com
   
   Here's the brain teaser I read about and promptly forgot the solution
   (because I thought it would never happen to me). How does one delete a
   FILE named ".." I have the following at the root directory. 
     * /. a dir (which is normal)
     * /.. a dir (which is normal)
     * /.. a file (which is not normal)
       
   How this happened I don't know. How to remove this not-bothering-me
   file has me stumped. Got an answer? 
   
   I suspect that this file is actually named something like: "/.. "
   (note the trailing space!).
   
   In any event you can remove this with a command like
        find / -type f -maxdepth 1 -name '..*' -print0 | xargs -0 rm
-i

   Note: you must use the GNU versions of find, xargs, and rm to ensure
   that these features (-print0, -0, and -i) are available. (They may be
   available in other implmentations -- but you must check first).
   
   The find parameters here specify files (not directories, symlinks,
   device nodes, sockets, or FIFO's) and force it to only search the
   named directory (or directories if you list more than just /). The
   -print0 force it to be written as a null-terminated strings (thus the
   receive process on the other end of the pipe must be able to properly
   interpret null-terminated arguments -- which is what the -0 to xargs
   accomplishes).
   
   As far as I know there is no way to legally get a NUL character into a
   Unix filename. (Using a hex editor might get one in there -- but fsck
   would probably complain on its next pass).
   
   The -i on rm is just a little extra protection to prevent any other
   unexpected side effects. It forces rm to interactively inquire about
   each argument before removing it.
   
   -- Jim
     _________________________________________________________________
   
  Reminder!
  
   From: George Read gread-berkeley@worldnet.att.net
   
   I am a subscriber to caldera-users, but as a rank newbie, 99% of what
   gets posted is irrelevant to my situation and over my head. In fact,
   I'm looking for some real basic, preliminary information: 
   
   Perhaps you should consider some avenue of paid support. there are a
   number of consultants and even a 900 support line.
   
   Also, if you have access to IRC there are a few #Linux "channels." (If
   you've never heard of IRC -- or Internet Relay Chat -- then think of
   it as an online CB system -- similar to the "chatboards" and "chat
   lines" on various BBS' and online services (like CompuServe and AOL)).
   Granted IRC is a bear to figure out -- and 99.9% of what's written
   there is even less relevant or comprehensible than the traffic on this
   list. However the feedback is immediate and there are some people who
   will take time out from their usual chat aggenda to help.
   
   There's also that pesky "Answer Guy" from Linux Gazette ;) (but he's
   too ornery and doesn't help with X Windows stuff at all).
   
   1. A way to create a primary Linux partition on a drive that is
   entirely occupied by a dos active and a dos extended partition. The
   extended partition has 400MB available that does not have any data on
   it, but LISA 2.3 does not wish to give it a primary partition. 
   
   You have three choices here. You can repartition the drive using
   traditional methods (backup your data, reformat, re-install DOS and
   all applications, restore data). You can repartition using FIPS (a
   non-destructives partitioning program for DOS -- written by Linux or
   FreeBSD users from what I gather). If you use FIPS the process goes
   something like: do a backup, verify your backup, unfragment you DOS
   partitions, run CHKDSK and/or Norton Disk Doctor and/or SCANDISK, then
   run FIPS.
   
   Another approach -- and the only one I know of that doesn't involve
   repartitioning -- is to use MiniLinux or DOSLinux or XDenu. These
   distributions (of which DOSLinux is the most recent and must
   up-to-date) are designed to run on a UMSDOS partition (an MSDOS
   partition mounted under Linux with support for some Unix semantics).
   You would be running COL -- but you would be running Linux.
   
   You can find information about DOSLinux at Kent Robotti's home page:
   ftp://wauug.erols.com/pub/people/kent-robotti/doslinux/index.html
   (Kent is the creator and maintainer of DOSLinux).
   
   2. a workaround to a problem with RAWRITE3: I can't see my COL Base
   cdrom on a Nakamichi MDR7 jukebox that is controlled by a BusLogic
   946C, because Autoprobe can't find anything and I can't get RAWRITE3
   to write MODULES.IMG to a floppy on A:. 
   
   Have you tried supplying the "max_scsi_luns=7" parameter to the kernel
   during the bootup sequence (at the LILO prompt).
   
   Normal SCSI controllers support up to 7 devices. It is possible for
   these controllers to refer to "Logical Units" on any/all of these
   devices. These "logical unit numbers" or LUN's aren't very common --
   but are used by CD changers (which is why most of them are limited to
   6 or 7 CD's) and some tape changes (though those usually use a
   different mechanism to control tape changes and ejections) and some
   RAID subsystems and CD-ROM "towers."
   
   I have a NEC 7 platter CD changer which requires this parameter. This
   suggestion assumes that the problem is isolated to the CD drive -- and
   that your kernel (LISA's) is seeing the BusLogic card. If the problem
   is that you can't even see the SCSI controller -- then you probably
   want to look for an alternative boot/root diskette set and boot from
   that.
   
   One of the nice things about user's groups is that you can often have
   the phone numbers of some local Linux users that will cut you a custom
   kernel on request and let you pick up the floppy. I'd highly recommend
   finding (or starting) a local LUG. I've occasionally had people come
   over to my place where we could plug them onto my ethernet and suck
   all the free software they want across from one of my systems.
   
   (Which reminds me -- I've been meaning to get PLIP working for a
   couple of years now -- I should really get around to that).
   
   For these reasons, I ask: Is there any way to ask caldera-user users
   for some help on these two questions, sent to my own email address,
   and not have to read 20 or 30 messages that I can't profit from, at
   least until I get COL up and running. I had hoped from the name that
   Post-Only might be such an address, but I see that it is something
   very different.
   
   Caldera has some support options. I think some of them are extra cost
   items. Have you called them about your Caldera specific questions?
   
   At first blush it doesn't look like Caldera's COL is the best Linux
   distribution for your needs. If you're intent on using COL -- and
   particularly if you have a business need for Linux -- I'd recommend
   going out and buying an additional drive. For a couple hundred bucks
   (US) you can get a 2Gig external SCSI drive (www.corpsys.com if you
   don't have a suitable vendor handy).
   
   Even if you're just experimenting with Linux and don't want to
   "commit" to it -- an extra external SCSI drive with a couple of Gig of
   space is a handy investment for just about ANY operating system. It's
   pretty convenient to connect the extra drive, and just make a copy of
   everything from your main system.
   
   If your time is worth more than $20/hr you can easily make the case
   for buying a $200 to $300 hard drive. Doing full system and data
   backups, and verifying them prior to repartitioning can be pretty time
   consuming. Even if you already have a scheduled backup habit (let's
   face it -- most don't) and even if you have a regular recovery test
   plan (which almost nobody bothers with -- often to their detriment!)
   -- doing a major system change (like repartitioning) almost requires
   an extra "full" backup and test cycle.
   
   (I have customers who've run the cost vs. time numbers for their
   situations and justified buying a full system and hired me to do the
   configuration on the same basis. The "extra" system becomes part of
   the recovery plan for major system disasters).
   
   -- Jim
     _________________________________________________________________
   
  pcmcia ide Drives
  
   From: Alan C. Sklar CS266446@wcupa.edu
   
   I am trying to install a pcmcia drive through a kit I purchased.. I
   got the drive all ready I formatted it with a desktop machine and bot
   my win 95 and linux partitions are defiend... But now when I go and
   boot linux I send the commad ide2=0x170 and it loads it identifies the
   right drive but I get all sort of errors... Can you help?
   C. Alan Sklar 
   
   I don't have enough information to help with this one. Is this a
   laptop or a desktop with a PCMCIA adapter installed? In either event
   what is the make/model of the system?
   
   Do you have PCMCIA support installed and built into the kernel? What
   modules do you have loaded? What does your /etc/pcmcia/config.opts
   file look like? What type of hard drive is this (make and model)?
   
   -- Jim
     _________________________________________________________________
   
  KDE BETA 1
  
   From: Eric Wood eric@interplas.com
   
   This should be the most handy tip known to man! If a certain
   application (I don't care what it is) complains about missing a
   library and you know that the library it's wanting is in a certain
   directory THEN: 
    1. Add *that* directory to the /etc/ld.so.conf file.
    2. Rerun /sbin/ldconfig
       
   That's it. What is does is it tells Linux to search the directories
   specified in /etc/ld.so.conf for library files. Forget about the
   stupid LD_LIBRARY_PATH variable. Everyone: Please read the ld.so man
   page for further knowledge.
   Eric Wood 
   
   I recently trashed my /etc/ld.so.cache file and had forgotten how to
   fix it (since the last time I'd had a damaged ld.so.cache was on an
   old Sun a couple of years ago -- and I've never had one on a Linux box
   before.
   
   Post that to your tech support archives:
   
   System hangs on boot -- even with -b and single switches -- or it
   gives messages like "unable to open ls.so.cache" in a seemingly
   endless stream:
                Run /sbin/ldconfig!

   -- Jim
     _________________________________________________________________
   
  Compression Program
  
   From: Cygnus caldera-users@rim.caldera.com
   
   Anyone know of any programs for linux that decompress multi-part
   (multi-disk) .zip archives? I can't find a one.
   -Cygnus 
   
   Most Linux distributions come with the free zip/unzip package. Here's
   the -L (license) notice from my Red Hat 4.2
   
   "Copyright (C) 1990-1996 Mark Adler, Richard B. Wales, Jean-loup
   Gailly Onno van der Linden and Kai Uwe Rommel. Type 'zip -L' for the
   software License.
   
   Permission is granted to any individual or institution to use, copy,
   or redistribute this executable so long as it is not modified and that
   it is not sold for profit."
   
   I think there's a source package for "Info-zip" also floating around.
   I don't know if this is Info-zip or an independent version -- looking
   in /usr/doc/unzip*/COPYING I find Mr. Rommel listed -- and that
   document is definitely about Info-zip.
   
   For the future you might try the 'locate' command -- which is fairly
   common among Linux distributions. The command:
                locate zip

   ... will quickly find every file with "zip" in the name or path that
   was on your system during the last "updatedb" run (which is typically
   a cron job that's run nightly).
   
   -- Jim
     _________________________________________________________________
   
  loadlin
  
   From: Scott Williamsscott@gyst.net
   
   Answer guy, To run LOADLIN I need to have a copy of the LINUX kernel
   on one of my dos partitions, and an initial swap space. No where can I
   find an actual explaination on how to do this correctly. 
   
   You don't need an initial swap space to run LOADLIN or to load the
   kernel. If you have 8Mb or more of RAM you don't "need" to have a swap
   space at all -- but you'll probably want one. You can swap to a file
   or a partition -- or even several of each. Assuming that you don't
   have Linux installed yet you can view man pages for most Linux/GNU
   commands, functions, packages, and configuration files at:
   http://www.ssc.com/linux/man.html
   
   ... in particular you want to read the mkswap(1) and the swapon(8).
   The man pages there are accessed via a CGI script so you have to post
   data to a form to access the individual pages. Thus I can't give URL's
   directly to the pages in question. That's an unfortunate design
   decision by the web master at SSC -- it would be more convenient to
   access (and cause less server load and latency) if they used a cron
   job to periodically update a tree of static HTML pages and saved the
   CGI just for searching them.
   
   Every time I try to copy the kernel to a dos diskette, Linux
   overwrites the formatting. DOS then cannot recognize the file from the
   LOADLIN command. 
   
   It sounds like you're using 'dd' or RAWRITE.EXE to prepare these
   diskettes. That's fine for transferring boot/root images -- but has
   nothing to do with LOADLIN. To use LOADLIN.EXE you copy the kernel
   image to a plain old DOS file.
   
   I haven't even gotten far enough to think about creating an initial
   swap space... Any advice on the subject?
   Scott 
   
   I'd consider getting a copy of DOSLinux from
   ftp://ftp.waaug.erols.com/pub/people/kent-robotti/doslinux.html (Yes
   there are still some people out there serving HTML pages via FTP --
   nothing in the HTML spec *requires* that HTTP be used as the transport
   mechanism).
   
   Kent Robotti has been working on this distribution for awhile. It
   takes about 32Mb of space on a DOS partition -- and comes as a set of
   six 1.44Mb files (so if fits on a half dozen diskettes). You then add
   a kernel for SCSI or IDE use.
   
   Basically DOSLinux works like this. You get all the RAR files (RAR is
   a Russian Archiving Program like PKZIP, SEA ARC, ARJ, LHARC, ZOO, or
   whatever). The first image is a self-extracting file (an archive which
   is linked with a DOS binary of the decompression program -- a common
   DOS technique among archiving programs). You put these all in a given
   directory and run the self-extractor (DOSLNX49.EXE as I write this --
   it was at "48" a couple weeks ago) from C:\. It thenn extracts all of
   these images to C:\LINUX directory.
   
   This provides a complete (though minimal) Linux distribution. It also
   shows how to configure a system to use LOADLIN with a UMSDOS root
   partition.
   
   I realize that you may be intending on use something like Red Hat,
   Slackware, or Debian on a third hard drive, or a removable drive or
   some other device that LILO just can't see (because you BIOS can't
   "see" it). You can do that -- and I've done in many times (I first
   used LOADLIN in about 1994 for exactly that purpose -- with the
   magneto optical drive I still use). However, if the README's and
   examples that come out of the LOADLIN package aren't helping you use
   if for that purpose -- than installing DOSLinux may help get you
   rolling and serve as a vang DOSLinux may help get you rolling and
   serve as a valuable example. -- Jim
     _________________________________________________________________
   
  WipeOut
  
   From: Falko Braeutigam falko@softwarebuero.de 
   
   Hi, in Linux Gazette Issue 22 there was a question about the WipeOut
   IDE. Your answer was that you never heard about WipeOut :-( Please
   check ShortBytes of Issue #19 - there is an announcement of WipeOut.
   WipeOut has nothing to do with xwpe. It _is_ an IDE for C++ and Java.
   There is just a new release ->
   http://www.softwarebuero.de/index-eng.html.
   Regards,
   Falko 
   
   This definitely counts as my biggest flub in the 10 months that I've
   been writing this column. I've gotten about 10 messages correcting me
   on this point.
   
   -- Jim
     _________________________________________________________________
   
                     Copyright © 1997, James T. Dennis
          Published in Issue 23 of the Linux Gazette December 1997
     _________________________________________________________________
   
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     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
        Boulder Linux Users Group -- Best of Luck to Michael Hammel
                                      
                               By Wayde Allen
     _________________________________________________________________
   
   Well since Michael Hammel was our featured speaker for the evening we
   had our obligatory snow storm (grin). It is amazing that every time he
   attends one of our meetings this happens. Nevertheless, we still had
   24 people in attendance.
   
   For those of you who don't know Michael, he writes the Graphic Muse
   column for Linux Gazette, maintains the Linux Graphics mini-HowTO,
   helps administer the internet Ray Tracing Competition, coauthored the
   UNIX Web Server book, designed the magazine cover for the November
   issue of Linux Journal, and is also the author of a four part article
   "The Quick Start Guide to the GIMP" now running in Linux Journal.
   
   His presentation started out with a demo of the GNU Image Manipulation
   Program (GIMP) showcasing many of its features, and perhaps more
   importantly giving us all an idea of what it could do. The discussion
   then turned to GUI builders. The group discussed their experiences,
   likes, dislikes, advantages, disadvantages, and general opinions of
   many different GUI design software packages. Supporting this
   discussion, Michael showed us examples of GUI building using XForms (I
   hope I've got this right) and Visual TCL.
   
   After this discussion, Michael showed a 10 minute video tape of Toy
   Story animated shorts done by Pixar. I think that everyone got a few
   good laughs from this. We then held a drawing for two CD's from the
   Internet Ray Tracing competition, and a copy of the November Linux
   Journal. As usual, we wrapped up the evening with a general discussion
   of Linux related topics.
   
   Since Michael is moving to Dallas next week, I particularly want to
   thank him for his support of our group!!! I have appreciated him
   taking the time to talk to us, and have always enjoyed his
   presentations. I want to wish him the best of luck at his new job. It
   might be a good idea to warn the North Texas Linux User's Group of an
   impending change in their weather though (very big grin). Perhaps he
   can continue to participate in our discussions on the mailing list?
     _________________________________________________________________
   
                       Copyright © 1997, Wayde Allen
           Published in Issue 23 of Linux Gazette, December 1997
     _________________________________________________________________
   
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     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
               CLUELESS at the Prompt: A Column for New Users
                                      
                                By Mike List
     _________________________________________________________________
   
                                  [INLINE]
                                      
    Welcome to installment 8 of Clueless at the Prompt: a column for new users.
     _________________________________________________________________
   
   .bashrc and .bash_profile Well, I found out why the bash dotfiles I
   talked about last month didn't work, and there were a couple things I
   did wrong. First I didn't recognize the difference between instances
   of bash and how they differ.
     * bash as a login shell reads instructions from .bash_profile
     * bash as used in any other instance is a non-login shell and will
       either use .bashrc or no .dotfile depending on what -option you
       assign to it.
     * presumably the same could go for any preferred shellrc files
     * the correct way to specify an alias is
 alias xx=whatever -options.
   notice that there is no white space between the alias name, the equal
       sign, and the command that the alias represents
       
   Besides aliases you can do also change the color of your console
   screen with your .bashrc or .bash_profile, by using commands like:

"/dev/tty1") setterm -background green -foreground black -store;;

   By the way I found this out by reading back issues of the Linux
   Gazette, and you might find some other little gems, just by digging
   into past issues.
     _________________________________________________________________
   
   Installing Software
   
   One very tricky procedure for new linuxers is installing software.
   Several months ago I touched on this subject, apparently not in enough
   depth, so I'm going to give it another go this time with a little more
   experience under my belt. The best advice I can give you if you are
   using debian, redhat, or caldera distributions is to look for the
   software you would like in a compatible package format, ie. RPM for
   redhat-caldera, and deb for debian. These are most commonly binaries
   and don't require much to get running.Slackware has packages in tgz
   format, but this can be misleading, as some source packages are
   inexplicably given a .tgz extension. If you get your software from the
   CDROM you should be set, with packages for a given distribution on
   that CD. Ifg you got your distribution from an ftp site, try using the
   most appropriate software found on that site, to see if it fits your
   needs. If not, you should check out the Linux Software Map, to see
   what kind of alternatives there are for the kind of applications you
   want. if you have disk space, I recommend that you choose a couple
   that seem to be close to what you are looking for, install them and
   use them for a short period to see which is more suitable for your
   uses. Sad but true, some software compiles easily, but you will
   probably find that many others take some hacking, and some doesn't
   seem to compile at all. You are at a distinct advantage if your Linux
   distribution conforms to the Linux FSSTND, which tends to assure that
   paths to libraries are the same in your distribution as they were in
   the distribution that they were written for/in. With enough hacking
   however, all of the software that has been compiled on one
   distribution can be compiled on any other.
     * Use Midnight commander or similar filemanager to look at the
       contents of the compressed archive for clues. look at files called
       README, README.elf, INSTALL or other similarly named files for
       information on how to compile or install them. This isn't always
       easy as it sounds, but often directions are specific enough to get
       you on your way.
     * before unpacking a tarball create a directory to unpack it in and
       cd to it before using
 tar -zxvf filename
   to unpack it, since sometimes the untarring doesn't create a separate
       directory and if you just unpack it in an existing directory you
       could get a real ugly situation when you get a bunch of disjointed
       files cluttering up your directory. you can also use tar -cxvf or
       similar combination to get a listing of the files that would be
       unleashed when you use the -z option. This will tell you if the
       files have a designated pathname which means that it will create
       its own directories and subdirectories that will keep the parent
       directory nice and tidy.
     * It's a very good idea to print out the README, INSTALL or similar
       files before you start to compile the software, so you can refer
       to the documentation as you go. If you don't have lpr configured
       properly yet, you can use
cat README |pr -l 56 >/dev/lp0
   (or lp1, or whatever). Using the -l 56 option should paginate the file
       so that page breaks occur where they should.
     * When you read the documentation, keep an eye out for any
       indication that you need, say Motif or Xforms or other libraries
       or toolkits that you don't have installed,if you don't have them
       you won't have a compiled application either.
     * Alternatively to printing the documentation out to paper, if you
       have X installed use separate xterms to view the docs and
       configure, and make the application.
     * Remember, most Linux archive maintainers keep a close eye on their
       sites so it's safe to download and install a binary if it's
       available.
     _________________________________________________________________
   
   I'm not really a Linux guru, and I'm starting to get into more
   advanced (??) stuff, and my intent was and still is to present
   information that a new user can implement now and research at his/her
   convenience, I'm not trying to be the Weekend Mechanic OR the Answer
   Guy, although I aspire to their level of Linux prowess. Briefly put,
   although it's a little late to be brief, I may not be appearing
   monthly after this issue, since I don't want to write just to hear
   myself type, I'll likely post a column when I can nail down a column's
   worth of information.
     _________________________________________________________________
   
   I still invite questions, suggestions, reasonable criticism and just
   plain e-mail:
   
                             troll@net-link.net
                                      
                         Don't M$ out, try Linux!!
     _________________________________________________________________
   
                        Copyright © 1997, Mike List
           Published in Issue 23 of Linux Gazette, December 1997
     _________________________________________________________________
   
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     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                              COMDEX/Fall '97
                                      
                            By Carlie Fairchild
     _________________________________________________________________
   
   Las Vegas, Nevada is host each year to one of the largest technology
   trade shows in the U.S.--COMDEX/Fall. This year nearly 220,000
   industry professionals lined up to find, test and research the latest
   technologies from the leading industry vendors.
   
   Earlier in the year the staff of Linux Journal volunteered to
   coordinate the COMDEX/Fall Linux Pavilion. Coordinating the event
   turned out to mean hours of preparation, and, luckily, vendors were
   quick to lend a hand. Kit Cosper of Linux Hardware Solutions managed
   to talk the spirit of Linux into Softbank, the sponsor of the COMDEX
   show. As a result, COMDEX personnel were very cooperative and worked
   with us to ensure that the floor space for the pavilion was in the
   best possible site; that is, we weren't hidden away in a back corner.
   
   Attendees seemed pleased to find many of their favorite Linux vendors
   in one convenient and easy-to-find area. Vendors present included
   Caldera, Linux Hardware Solutions, Enhanced Software Technologies,
   S.u.S.E., Red Hat Software, Hard Data, Quant-X, Infomagic, LinuxMall,
   Linux International and, of course, Linux Journal.
   
   Jon "maddog" Hall barely held his own against the hordes of Linux
   enthusiasts visiting the Linux International booth. Several members of
   the Linux community kindly volunteered their time to staff the Linux
   International booth, answering questions and spreading the word about
   Linux. Volunteers included Marc Merlin, Ira Abramov, Dan Peri and
   Richard Demanowski.
   
   Red Hat Software announced the December 1 release of Red Hat Linux
   5.0. To mark the event, Red Hat balloons filled the Linux Pavilion
   area of the convention center. The Linux mascot, Tux the penguin, was
   carried away in all of the excitement (see photo).
   
   S.u.S.E., a popular European Linux vendor, also announced the latest
   release of their Linux distribution, S.u.S.E. 5.1. This was S.u.S.E.'s
   first appearance at COMDEX, and considering their rapid growth in the
   U.S. market, it will most likely not be their last. Their distribution
   demonstrations proved to be great crowd pleasers, compliments of Bodo,
   Rolf, Michael and James Gray, the President of S.u.S.E. U.S. (See
   review of S.u.S.E. in this issue.)
   
   Clarica Grove, Britta Kuybus and I staffed the Linux Journal booth. We
   were quite pleased with the turnout of this year's show. During last
   year's COMDEX, we were kept busy explaining what Linux is to all
   comers. We were pleased to find that this year's COMDEX attendees had
   remembered and done their homework from last year. Not only did most
   people we spoke with know about Linux, but many of them are using it
   and very excited with their results. It goes to show that the
   popularity of Linux is indeed growing. Linux is being looked at more
   than ever as a cost-effective, viable operating system. Thanks to
   years of dedicated work by all of the Linux vendors, Linux
   International and the Linux community, we are now able to begin
   enjoying the success of Linux. This year's COMDEX Linux Pavilion was a
   showcase of this success.
   
   Linux Journal would like to thank everyone involved with this year's
   show--look forward to seeing you there next year.
     _________________________________________________________________
   
                     Copyright © 1997, Carlie Fairchild
         Published in Issue 23 of the Linux Gazette, December 1997
     _________________________________________________________________
   
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     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
              Configuring procmail with The Dotfile Generator
                                      
                             By Jesper Pedersen
     _________________________________________________________________
   
   [LINK] In this article, I'll describe how to configure procmail using
   The Dotfile Generator (TDG for short). This will include:
     * How to sort mails coming from different mailing list
     * How to setup an auto reply filter, when you are on vacation
     * How to change some part of a letter, i.e. remove the signature
     * How to avoid that mail get lost!
       
   It might be a good idea to download the program. To do that, please go
   to the home page of TDG, to find the nearest mirror. You might also be
   interesting in reading the article I've written about TDG for Linux
   Journal.
     _________________________________________________________________
   
                                Starting TDG
                                      
   To start TDG with the procmail module, type dotfile procmail. Now a
   window should appear like in figure 1. As you can see, the module is
   split up in three pages, the first two are very simple, so lets start
   with the page called General Setup. This page can be seen in figure 2.
   
                                  [INLINE]
                                      
                                  Figure 1
                                      
                                  [INLINE]
                                      
                                  Figure 2
                                      
   On this page there are four things, to configure:
    1. The directory to use as prefix for all file operations. This is
       just for ease, since all file operations may be with full prefix.
    2. Your email address, will be used in preventing loop-backs.
    3. Configuration of log files. These are very useful, when you wish
       to investigate where the different mail went. If you turn on
       abstract logging, you may find the program mailstat very useful.
       (See The log file below)
    4. The search path, in which procmail may find the programs which it
       needs. Note this is only the programs, that you specify in filters
       etc.
     _________________________________________________________________
   
                             Avoiding lost mail
                                      
   Since procmail handles your incoming mail, the security is very
   important to this module. This means that you may backup your incoming
   mail in three different ways. To do this, go to the page called
   Backup. Part of it can be seen in figure 3.
   
                                  [INLINE]
                                  figure 3
                                      
   The first category of backup is to back up all incoming mail. The
   code, which must be generated to the procmailrc file for this, will be
   written as the very first line. This is to avoid that any errors in
   the generated procmail file will throw away any of your mails. This
   sort of backup is only a good idea when you at first start using the
   generated procmail file. The main drawback is that all incoming mail
   is saved in one file, and this file may become huge very fast.
   
   The second method is to backup all incoming mail, which are delivered
   by procmail. This may be a good idea to use, to verify that mail are
   sorted into the right places.
   
   The third method is to backup all mail, which makes it to your
   incoming mailbox. This mail are often mails, which do not come from a
   mailing list, and which are not junk mail to thrown away.
   
   In the first method, you have to specify the full filename. This is
   because this method has to be 100% full prof. In the next two methods
   you may build the file names from the current date and time. This
   makes it possible to save this sort of mail to folders, for the
   current year/month/week etc. E.g. a folder called
   backup-delivered-1997-July
   
   As an additional feature, you may keep the files as gziped files.
   
   The backup of delivered mail may be specified for each individual
   recipe, or for all recipes at once. (see figure 4 check box 9) To
   learn how to use the FillOut elements, which configures the file to
   save to, please see the Dotfile Generator article in Linux Journal.
     _________________________________________________________________
   
                           Setting up the recipes
                                      
   In procmail a central concept is a recipe. A recipe is a set of
   conditions, and a set of actions. All the actions are executed, if all
   of the conditions is fulfilled. Below is a few examples of conditions:
     * The letter comes from president@white.house.com
     * The subject is subscribe
     * The size of the letter is greater than 1Mb
     * The letter contain the text ...
       
   A list of actions may include:
     * Reply to the sender, that you are on holiday
     * forward the letter to another person
     * save the letter to a file
     * change some part of the letter (i.e. add a new header field, add
       some text to it etc.)
       
   A procmail configuration is a sequence of recipes. When a letter
   arrive, each recipe is checked to see if all its conditions are
   fulfilled. If they are, the actions of the recipe is executed.
   
   Procmail will finish testing recipes when one is matched, unless a
   flag is set to tell it, that this recipe should not stop the
   deliverment (see figure 4 check box 8). This means that the order of
   the recipes are important, since only the first recipe, which match
   will process the letter.
   
   If none of the recipes are fulfilled, or if the ones which are
   fulfills have check box 8 in figure 4 set, the letter is delivered to
   the incoming mailbox as if the procmail filter haven't been there at
   all.
   
   You configure the recipes on the page called ``Recipes''. This page
   can be seen in figure 4.
   
                                  [INLINE]
                                  figure 4
                                      
   What you see here is an ExtEntry. An ExtEntry is a widget, which
   repeats it elements as many times as necessary (just like a list box
   repeats the labels.) All what you see on this page, is one single
   recipe. To see a new recipe, you have to scroll the outer scroll bar
   (1). To add a new recipe, you have to press the button below the
   scroll bar.
   
   As described above, a recipe is a set of conditions. This set is also
   represented with an ExtEntry (2). To scroll to another condition in a
   recipe, you have to use scroll bar (2), and to add a new condition,
   you have to use the button below scroll bar (2).
   
   You may give each recipe a unique name, which will make it easier to
   find a given recipe. This name will also be written to the file with
   mail delivered by recipes (method 2 above), so you can see which
   recipe matched the actual letter. To give a recipe a name, use entry
   (3). At the right side of the entry, a button labeled Idx is located.
   This is a quick index to the outer ExtEntry (i.e. the recipes). If you
   press this button a list box will drop down, where you may select one
   of the recipes to scroll to, by its name.
   
The conditions of a recipe

   The most common condition one wishes to set up, is that one of the
   header fields matches a given regular expression, or that the body of
   the letter matches a given regular expression. To explain how to do
   that, lets first see what a header may look like.

From procmail-request@Informatik.RWTH-Aachen.DE  Tue Jan 28 16:30:46 1997
Date: Tue, 28 Jan 1997 10:06:28 -0500 (EST)
From: Rick Troxel <rick@helix.nih.gov>
Subject: Re: Lynx as an external viewer for pine
In-reply-to: <Pine.LNX.3.95.970128011626.3854C-100000@sushi.uni-bonn.de>
To: procmail mailing list <procmail@Informatik.RWTH-Aachen.DE>
Cc: "Robin S. Socha" <uzs8kb@uni-bonn.de>

   The very first line of the letter is special. This line has been
   written by the program sending the letter (often called sendmail).
   This header field is often always the same for a given mailing list,
   so to sort mail from a mailing list, it might be a good idea to read
   the letter with an ordinary file reader (NOT a mail reader, as it will
   seldom show this line). And copy this information to the pattern field
   (figure 4, label (6) ). As the element to match, you have to select
   Sendmail from in entry (5).
   
   Three special macros exists in procmail. These may be used, when
   matching header fields:
   
   TO
          This macro matches every destination specifications.
          
   FROM_DAEMON
          This should match when the letter comes from a daemon (which
          includes mailing lists). This is useful, to avoid creating a
          mail loop with some mailing list.
          
   FROM_MAILER
          An other regular expression, which matches that the letter
          comes from mail daemon.
          
   To see what these macros stand for, please refer to the manual page
   called procmailrc.
   
   There is a lot of header fields to chose between in the pull down menu
   (5), but if the one you wish to select isn't located there, you may
   type it yourself.
   
   The check box (4) may be used to negate the condition, i.e. the
   pattern shall not match to fulfill the condition.
   
Regular expressions

   So far, I have mentioned that you may type a regular expression in
   (6). In most cases, it may not be necessary to know anything about
   regular expressions, since the procmail module will take care of most
   of it for you. One thing may be worth to know anyway, and that is that
   you may match ``anything'' with .* This means that abc.*def will match
   anything which start with abc and ends with def, eg. abcdef or
   abcXXXXdef. To see a more detailed description of the set of regular
   expression, that procmail uses, you may press the button labeled
   Description
   
   One common pitfall is to forget to match everything at the start of
   the line. I.E. If you wish to set up a regular expression for the
   From: field above, it is not enough to give the pattern:
   rick@helix.nih.gov, since this is not at the start of the line, you
   have to tell procmail that every mail messages, which includes the
   text rick@helix.nih.gov is to be handled, I.E. insert .* in front of
   the email address.
   
Letting an external program decide whether a condition is fulfilled

   A final way to set up a condition is by using an external program to
   verify some conditions. This is done by pressing button (7). This will
   bring up a window with a FillOut like the one you can see in figure 3.
   This time, however, the entry has been replaced with a text box. In
   this text box you may type some commands, which reads either the
   header or the body on standard input. These command may refer to some
   header fields from the letter. The line (separated with a newline)
   will be joined together with a separating semicolon. This makes each
   line a separate command.
   
   Procmail will consider the condition fulfilled if the exit code from
   the program is 0 and not otherwise. This behavior may be changed with
   the check button (4) in figure 4.
     _________________________________________________________________
   
                                  Actions
                                      
   The actions, that this module can handle is split up in six parts.
   These are described in detail below. To activate an action, you first
   have to select the check box, which is located next to it. This is, to
   make it clear which actions are enabled for a given recipe.
   
Predesigned filters

   In the window which appear, when you press the button labeled
   Predesigned Filters, you may set up a filter. This filter may change
   the header fields, add new header fields and/or remove existing header
   fields.
   
   On this page you will find one custom-made filter: Remove signatures.
   With this filter, you may specify a signature for each email address.
   If the text you specify is found (exactly!) it will be removed from
   the letter. My intention is that more custom-made filters will be
   added, as users send me their ideas and filters.
   
Handmade filters

   If you wish to create your own filter, you have to go the page
   Handmade filters. On this page, you may send the header and/or the
   body of a letter through a command.
   
   As an example, you may remove the header with the command cat - >>
   /dev/null, or add a message to the body of a message with the command
   echo This letter has been resent to you, by my procmail filter!; cat -
   
   If only the filter actions is selected, the filter will change the
   letter permanently, i.e. the changes will have effect on the
   subsequent recipes (even on the delivered letter, if no recipe match!)
   This may be useful if you e.g. uses a mail reader, which does not
   support mime, and you have a filter, which can convert mime encoded
   text to 7 bit ascii.
   
   If however one of the other actions are enabled, the changes will only
   have effect within this recipe!
   
The reply action

   With the reply action, you may set up a reply mechanism, which sends a
   letter back to the sender, with a message you specify. One feature of
   this mechanism is that you may specify how often a reply should be
   send, you have the following possibilities.
     * Send a reply to each letter
     * Send a reply only once
     * Send only a reply if it is more than a given number of days since
       the last reply was send.
       
   This is useful, if you leave on vacation, and wish to send a message
   that you will not read your letter at once.
   
   The reply is only sent, if the letter does not come from a daemon, to
   avoid that you sent a reply to every message on a mailing list.
   
The forward action

   With the forward action, you may forward letters to other email
   accounts.
   
The save to file action

   With this action, you may save the letter to a file. The file name is
   specified with a FillOut widget, just like you specified the name of a
   file to save backups to. This time, however, you have two additional
   features: you may use the content of a header field, or you may use
   the output from a command. In figure 5, you can see how to select a
   header field to extract as part of the file name.
   
                                  [INLINE]
                                  figure 5
                                      
   Email addresses may be given in three ways:
     * real name <email>
     * email (real name)
     * email
       
   If you select that the field is an email address, you may specify that
   you wish to extract the user name with or without the domain part.
   
   Finally, you may pipe the header field though a command you specify
   yourself. This command may read the value of the header field on
   standard input, and write to standard output.
   
The pipe action

   With the pipe action, you may specify a command, which takes care of
   the letter. This command may read the letter on standard input, and
   may not write anything (it will be ignored!).
     _________________________________________________________________
   
                                The log file
                                      
   The procmail file generated from TDG, contain lots of comments, which
   should make it easy for you to find a specific recipe, in case you
   wish to see what it look like.
   
   Should something go wrong, you may turn on extended diagnostic, this
   will write additional lines to the log file, which lets you see what
   it does. To debug this, you have to read both the log file and the
   procmail file.
   
   If you use the log abstract options, you will find the program
   mailstat very useful. This will tell you how many letters have been
   delivered where. One line in the output from the mailstat programs is
   fake, and that is the line, which says: /bin/false. This line is due
   to the way that the generated code look. When you wish to throw away a
   letter, in a way so you can explicit see that is has been dumped, you
   should deliver it to the file called /dev/null. Please note that you
   can only use the mailstat program, if extended diagnostic is turned
   off.
     _________________________________________________________________
   
                                  The End
                                      
   Before procmail start filtering all your incoming mail, you have to
   add the following line to the file called ~/.forward:

"|IFS=' ' &&exec /usr/local/bin/procmail -f-||exit 75 #YOUR_USERNAME"

   With the correct pathname for procmail, and your email address
   replaced with YOUR_USERNAME
   
   Here's a few link, which you may find interesting:
   
   The procmail mailing list
          To subscribe to the procmail mailing list, send a letter to
          procmail-request@informatik.rwth-aachen.de. Letters to it
          should be send to procmail@informatik.rwth-aachen.de
          
   Procmail Mini-Tutorial in Linux Gazette
          In The Linux Gazette issue 14, Jim Dennis has written a mini
          howto on procmail
          
   Procmail Mini-FAQ
          Era Eriksson Has created an excellent FAQ for procmail, which
          may be worth visiting before you ask anything on the mailing
          list
          
   The home page of the Dotfile Generator
          At the home page of The Dotfile Generator, you may find
          additional information about the other modules, which TDG
          contains (at the moment this include: Bash, Elm, Emacs,
          ipfwadm, Fvwm1, Fvwm2, Tcsh and Rtin).
     _________________________________________________________________
   
                     Copyright © 1997, Jesper Pedersen
         Published in Issue 23 of the Linux Gazette, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next 
     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
   
   Welcome to the Graphics Muse
   
    Set your browser as wide as you'd like now.  I've fixed the Muse to
                    expand to fill the aviailable space!
                                      
                               © 1997 by mjh
                                      
   
   ______________________________________________________________________
   
   Button Bar muse:
    1. v; to become absorbed in thought
    2. n; [ fr. Any of the nine sister goddesses of learning and the arts
       in Greek Mythology ]: a source of inspiration
       
     W elcome to the Graphics Muse! Why a "muse"? Well, except for the
   sisters aspect, the above definitions are pretty much the way I'd
   describe my own interest in computer graphics: it keeps me deep in
   thought and it is a daily source of inspiration.
   
            [Graphics Mews][WebWonderings][Musings] [Resources]
                                      
   
   T his column is dedicated to the use, creation, distribution, and
   discussion of computer graphics tools for Linux systems.
   
         Can it be true?  Has it really been a whole year for the Muse?
   Time surely travels more quickly as we grow older.  The lazy days of
   youth have left me forever, replaced by the hectic life of adulthood
   and responsibility.  I love it.  No wonder life was so confusing for
   me as a youth.  I was bored.
   
   So, another busy month gone by.  I'm still in the throws of
   pre-shipment testing at work but fortunately my code seems to be
   pretty stable now.  I've even managed to get far enough ahead that
   I've been able to work at home on other projects while the rest of the
   gang catches up.  To their credit, their stuff was harder to work on
   than mine.  I got to design and write my code from scratch.  No legacy
   code for me.
   
   One of the things I've been working on is getting deeper into the
   GIMP.  If you haven't seen it yet, take a look at the November Linux
   Journal.  The first of a 4 part series I wrote on the GIMP was
   published in that issue.  I also have started to learn much more about
   how to create interesting effects.  If you have some free time and
   online-money to burn, check out my GIMP Gallery.  I've put most of my
   more interesting images there.
   
   This month I'm going to talk a little about how to use the GIMP to
   create a frame with a 3D metallic or plastic look.  The process turns
   out to be fairly simply and is one you will probably get to know by
   heart if you use the GIMP very often.
   
   I'll also cover my notes from SIGGRAPH '97.  I wish I could have done
   this right after I got back when the conference was still fresh in my
   mind, but things didn't work out that way.
   
   Finally, I'll be covering JavaScript image rollovers - those cute
   little image swapping thingies that many people have added to their
   Web pages.  You can do these using a number of different techniques,
   but I'm only familiar with JavaScript right now so thats what we'll
   talk about.
   
   As usual, feel free to send me comments on any of this.
   
   Graphics Mews       Disclaimer: Before I get too far into this I
   should note that any of the news items I post in this section are just
   that - news. Either I happened to run across them via some mailing
   list I was on, via some Usenet newsgroup, or via email from someone.
   I'm not necessarily endorsing these products (some of which may be
   commercial), I'm just letting you know I'd heard about them in the
   past month.
   
   indent
   
CurveSoft announces release of FontScope.

   CurveSoft(tm) is pleased to announce the availability of
   FontScope(tm): A commercial, high-performance portable rasterizer
   ibrary for Type 1 scalable fonts sometimes also called PostScript(tm)
   fonts.
   
   FontScope allows developers and programmers to build Type 1 scalable
   font support directly into their applications thus roviding a fast,
   efficient, high quality platform-independent solution to the problem
   of providing scalable font support.
   
   See http://www.curvesoft.com for further details about the product.
   
   FREE DEMO
   You can download a free demo for the Linux(x86) and SunOS(SPARC)
   platforms from the web page at http://www.curvesoft.com . The demo
   lets you arbitrarily scale, skew or rotate characters from any Type 1
   font you may have and view either the bitmap or the outline on the
   screen. If you have Multiple Master fonts, it lets you create
   instances and then view characters from those instances.
   
   If you have access to a Linux(x86) or a SunOS(SPARC) machine, we
   strongly suggest downloading the demo program since that allows you to
   test FontScope on your own Type 1 fonts as well as get an idea of
   thespeed and quality. If unanswered questions still remain, please
   email them to info@curvesoft.com indent
   
The GRASP Environment for Ada 95, C, Java, VHDL

   GRASP is commercial grade GUI front-end for GNAT, gcc, and JDK. Users
   can compile, edit, and run programs directly from GRASP. The editor
   provides complete syntax coloring with user selected colors and
   fonts.
   
   GRASP provides complete support for generating, editing, and printing
   Control Structure Diagrams (CSDs) from Ada 95, C, Java, and VHDL
   source code. The CSD is a diagram intended to increase the
   comprehension efficiency of source code.
   
   GRASP runs under SunOS/Solaris, IRIX, Linux, and WinNT. It is freely
   available via the GRASP homepage at
   http://www.eng.auburn.edu/grasp
   
   
   [INLINE]
   
   
   The Texture Library-mirror in Vienna has changed. Please update your
   bookmarks and links from:
   
                     http://klein.htu.tuwien.ac.at/~rs/
                                      
                                     to
                                      
                       http://freibier.ml.org/texlib/
                                      
   
   [INLINE] [INLINE]
   [INLINE]
   
    Did You Know?
    
   ... Adobe Acrobat contains some nice fonts you can use with your X
   Windows environment? You get these scalable PostScript fonts:
   
   
          Courier-Bold Courier-BoldOblique Courier-Oblique Courier
     Helvetica-Bold Helvetica-BoldOblique  Helvetica-Oblique Helvetica
            Times-Bold Times-BoldItalic Times-Italic Times-Roman
                AdobeSansMM AdobeSerifMM Symbol ZapfDingbats
                                      
   I checked the License file and there doesn't appear to be anything
   against using these for general use on your system, but you should
   read the License yourself to be certain. Then search all the old
   CD-ROMs you can find for *.pfa and *.pfb files. For example, Lotus 123
   v1.1 for Windows has these:
   
   
              ArialMT Bodoni-BoldCondensed BrushScript Courier
                 DomCasual LetterGothic NewsGothic Perpetua
   Symbol TimesNewRomanPS TimesNewRomanPS-Bold TimesNewRomanPS-BoldItalic
                           TimesNewRomanPS-Italic
                                      
   You can then use the Type1Inst script to set up the directories with
   the new files. Don't forget to run xset to tell your X server about
   the new directories!
   
    Q and A
    
   Q:  Whats the latest on VRML?
   
   A:  Check out the VRML update on BUILDER.COM:
   
      http://www.cnet.com/Content/Builder/Authoring/Vrml/index.html?dd
                                      
   Q:  Whats the latest news on commercial game development for Linux?
   
   A:  There was an important announcement from Crack.com recently.
   Check out
   
            http://www.gamecenter.com/News/Item/0,3,1190,00.html
                                      
   
   [INLINE]
   
Reader Mail

   Dr. Norman Fahrer <fano@norcov.com> wrote:  [INLINE]
   I read your article in the Linux journal. I was running the older
       version of gimp (0.5..) and yesterday I wanted to get the new gimp
       version running.
       
   'Muse:  The 0.5 is quite old.  0.61 was the last publicly released
   Motif version.
   I configured + compiled + installed.  Everything built fine. Now when
       I type 'gimp' it says :
        gimp: can't load library 'libgtk.so.1'
       I have that library built and installed into /usr/local/lib where
       it is symboliclly linked to 'libgtk.so.1.0.0'. Do you have any
       idea what I can do to get the Gimp running ? Thanks for your help,
       
   'Muse:  After installing the GTK library, be sure the loader knows
   about it.  First run "ldconfig -p | grep gtk" to see if it already
   does know about the GTK library.  If you get no output from this then
   run "ldconfig" again, but without the -p option.  When that completes,
   run "ldconfig -p | grep gtk" to verify the library can be found.
   You'll need to run ldconfig as the root user if you've installed the
   library in /usr/local/lib.
   
   ldconfig generally looks in /usr/local/lib, along with a few other
   places, for libraries.  To make sure it does, check /etc/ld.so.conf
   and make sure that directoy is listed there.  Check the man pages for
   ldconfig if you have any further problems.
   
   If ldconfig -p shows gtk is already installed then the other
   possibility is to add the following to your .profile:
   LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
       export LD_LIBRARY_PATH
       
   This may help the loader find the library at run time too.
   
   kar@webline.dk wrote:
   Do you know of a tool that can convert Corel's cdr and wpg formats
       into a more commonly accessibly format?
       
   'Muse:  Image Alchemy supports wpg.  It may also support cdr by now
   although the version I have doesn't list it (I know there are a number
   of formats it supports that aren't listed, however).  Check out my
   Graphics Muse column in the August 1997 Linux Gazette.  There are
   links there to their web site. The Linux Gazette is at
   http://www.ssc.com/lg.
   It's a little much to buy a package just for that - perhaps you could
       ask in your column if anybody knows other programs that can?
       
   'Muse:  Ok.  So readers, anyone know of a cheaper method?  If so send
   it to him.  I'm satisfied with knowing there is a commercial solution.
   
   Tethys <tethys@ml.com> wrote in respose to a Musing last month about
   NetPBM not having JPEG conversion tools:
   Yes, you're right. Netpbm doesn't come with tools to convert to and
       from JPEG. Maybe it should. However, this is probably because the
       libjpeg distribution that it would use already comes with cjpeg
       and djpeg. By default, these already act like ppmtojpg and
       jpgtoppm. They also accept other formats like GIF, BMP, TGA etc.
       
   David Maha <cmulator@pacific.net.sg> wrote:
   My installation diskette for my image256 software was destroyed by
       coffee, and I've been looking for the software for quite some time
       now. I have a A4 Tech A4Color AC 4096 hand-held scanner. Do you
       know of which software can be used to operate the scanner and if
       possible in Windows environment? Can you tell me where I could
       download it or get it on the net?
       
   'Muse:  I'm not familiar with MS platforms.  I don't use them.
   However, there are apparently some Linux drivers for this scanner on
   the Sunsite Linux archives. Take a look at:
   ftp://sunsite.unc.edu/pub/Linux/apps/graphics/scanners.
   
   I did a review of all the Linux scanner information I could find in my
   Graphics Muse column in March of this year.  You can take a look at it
   starting at the Linux Gazette's (which is the online magazine that
   carries my Graphics Muse column) table of contents at
   http://www.ssc.com/lg.
   
   Gregory Gardener <GardenerG@code20nl.npt.nuwc.navy.mil> wrote:
   I work for the DOD.  From reading your column in Linux Journal it
       appears that you have expertise in the area of PC graphics...so
       I'm directing my question to you. If I wanted to develop a PC
       software product--an interactive educational system--what PC
       graphics package is "state of the art" for Linux or Windows?
       
   'Muse:  Good question.
   
   Don't choose a platform, choose a technology:  Java and/or VRML.
   Why?  By doing so you remove the need for your end users to be
   required to have a particular platform to use your software.  Second,
   you can more easily fit into any organization no matter what platforms
   they might already have.
   
   Problems:
    1. Java is not quite standard on all platforms yet.
    2. VRML is very new and has the traditional problems with new
       technologies (acceptance, standards, etc).
    3. VRML requires the availability of a VRML browser on your end-users
       platforms.
       
   #1 is not going to be a problem by the middle of next year (my guess).
   Depending on your roll-out date it might be worth starting with Java
   right from the start.  In fact, I'm investing my own time in learning
   Java.  I do GUI development for a living and feel my skills in X may
   not be enough for the long run.  Java GUI is the next big thing for
   people like me.
   
   #3 is a problem.  There are only a few VRML browsers for Linux right
   now and I don't know much abou them.  Liquid Reality is one - it
   requires you have the Java runtime environment installed and working.
   VRML on non-Linux is actually better supported right now, but thats
   probably a situation that will be fixed within the next year (again,
   my guess).
   
   Now, assume you go with these two.  Now you can choose your *own*
   development platform.  I'd pick Linux.  Why?  Because MS is not being
   very forthcoming about their support of Java - Linux has embraced it
   quite happily.  I'm just getting started with Java development so I
   can't tell you how to use the tools, but the Java Development Kit
   (JDK), all the way up to version 1.1.3, has been ported to Linux.
   There is a commercial Java IDE kit, Vibe, for Linux already.
   
   VRML is like HTML and you can write it using vi or EMACS or whatever
   text editor you'd like.  Eventually there will be WYSIWYG editors for
   VRML, but for now it shouldn't be difficult to do by hand.  In fact,
   many of the current VRML texts are written from the point of view that
   you are writing it by hand.
   
   Alternatives:  OpenGL/Motif/C.  This is the way I'd do it right now
   simply because I already now Motif and C and OpenGL is something I've
   been studying off and on for a few months now.  I really like OpenGL,
   but if you use Motif/C your application is less portable across
   platforms (ie its not very easy to port to MS or Macs).  OpenGL has
   been ported to lots of platforms, but it doesn't provide a windowing
   toolkit so you have to use it with a toolkit native to your platforms
   (Motif/X, MS Windows, etc).
   
   Now, this still might not address your problem because "an interactive
   educational system" can encompass all sorts of display data so its
   hard to say if Java/VRML will work for you.  What sort of graphics do
   you need to display?  How do they need to be displayed?  User
   Interfaces (UI's) is a big area of study that few people hear about
   because the hype from the technologies you use for them gets more
   attention.  The problem still exists - which technology do you use?
   The answer - whatever one you're most comfortable with for now.
   Eventually, you need to get familiar with Java and VRML.
   ______________________________________________________________________
   
   [INLINE]
   
Adding JavaScript rollovers to Web pages.

   Last month I talked about browser detection with JavaScript.  Like
   most Web technologies, JavaScript is new and prone to problems, even
   within the applications for which it was developed - the Netscape
   Navigator Web browser.  In order to make the best use of JavaScript
   with Netscape Browsers you'll want to make sure you understand what
   versions of the browser support which JavaScript constructs.  Browser
   detection helps you do this.
   
   This month we'll talk about a common trick many people are using in
   their Web pages today:  image rollovers.  An image rolllover is an
   image that changes based on user input.  For example, if you look at
   my GIMP pages (you'll need Netscape 3.x or later for this) you'll see
   image rollovers in the menus.  When you place the mouse over the text
   for one of the menu items, the Gallery for example, the text
   background changes to a light blue or cyan color.  The text is
   actually an image, not ordinary HTML text.  When you place the mouse
   over the image it is swapped out for another image, the cyan colored
   version.  Thats a rollover.
   
   Adding rollovers is actually fairly easy.  First, you need to make two
   copies of an image (we're taking a very basic approach to this - you
   can actually create multiple versions of the image to be displayed
   based on different types of user input).  The first copy is the
   original, the image to be displayed initially or when no user input is
   being applied.  The second is the image to be swapped in when the user
   moves the mouse over the original or clicks on the image.  Creating
   these images can be done in any number of ways.  Personally, I use the
   GIMP.  Its well designed for these kind of image processing tasks.
   
   Next you need to understand how JavaScript interprets user input.
   These are called events.  There are number of different events that
   JavaScript can recognize  Not all are applicable to images, however,
   nor to use with rollovers.  The ones of interest are:
   
   
            Event Name Meaning JavaScript and Netscape versions
          onclick User clicks on an image. 1.0 (Navigator pre-3.x)
       onmouseover User moves the mouse over the image 1.0 (Navigator
                                  pre-3.x)
        onmouseout User moves cursor out from link or image map. 1.1
                              (Navigator 3.x)
   onmousedown User presses a mouse key down but doesn't release it. 1.2
                              (Navigator 4.x)
       onmouseup User releases the mouse button. 1.2 (Navigator 4.x)
                                      
              CAPTION: JavaScript Events useful for rollovers
                                      
   These are all fairly self explanatory.  They are all associated with
   the way a user handles the mouse in relation to the image. Note also
   that the event name is case insensitive.  You will often see examples
   where the evens are written like onMouseOver or onClick.
   
   Finally, you need to understand how JavaScript references images on a
   Web page.  The trick to rollovers is to update the correct image - in
   some cases the image to update is not the image over which the mouse
   currently rests.  For example, see my contents page where I update a
   central image when the mouse is placed over images that surround the
   central image.  That page doesn't do a good job checking which browser
   is being used and as a result it doesn't work well with non-Netscape
   3.x browsers, or even 3.x browsers on non-Unix platforms.  Still, the
   rollovers do work right on the Linux Netscape browser.
   
   JavaScript references images as objects and as such treats them just
   like any other object.  Images in a document (documents are HTML
   pages) are referenced using names, such as
   
   
                                   [LINK]
                              document.dog.src
                                      
   The document name means the current document (page), the dog name
   references the NAME= tag given to the above image, and the src name
   refers to the name of the image, such as "dog-1.gif".   You'll notice,
   if you have an appropriate browser (I was lazy - there is no browser
   detection code included!), that the above image changes when you place
   the mouse over the dog.  So does the text in the status bar at the
   bottom of the document.  Lets look at the code that handles this.
   
   First, lets look at the image's HTML definition:
   <A HREF="javascript:void(null)"
        onMouseOver="mouseIn('Happy Dog, eh?',); return true;"
            onMouseOut="mouseOut(); return true">
       <IMG SRC="../gx/hammel/dog-1.jpg" NAME="dog" BORDER=0 HEIGHT=240
       WIDTH=320>
       </A>
       
   Notice the name of the image:  NAME="dog".  This gives JavaScript the
   object reference it needs to access the correct image.  You can also
   access images using a documents images index, but thats a somewhat
   haphazard method (one I use with my contents page) and a bit harder to
   use.  I recommend using NAME tags for rollovers.
   
   A few other things we should note about this bit of HTML:
    1. There are event handlers for when the mouse enters the image area
       (onMouseOver) and for when the mouse leaves the image area
       (onMouseOut). We'll discuss the values we associate with each of
       these in a moment.
    2. The event handlers are placed in an anchor with an HREF tag.  The
       HREF points to a JavaScript function called "void", which is a
       simple method for doing nothing.  In this case we want only the
       event handlers to do anything and the anchor to do nothing.
    3. We've set the border width to 0 for the image so that no border
       will be placed around the image.  If we didn't do this a border
       would be added that used the link and visited-link colors because
       the image is wrapped in an anchor tag. This way, the image doesn't
       really look like a link.  Thats good, since its not really a link
       to anything.
       
   Before we talk about the event handlers, we should take a look at the
   JavaScript code:
   <SCRIPT LANGUAGE="JavaScript">
       <!-- Hide script from older browsers
       numitems=2;
       SampleImages = new Array(numitems);
       SampleImages[0] = new Image();
       SampleImages[1] = new Image();
       // Establish the two image objects we want to use.
       SampleImages[0].src="../gx/hammel/dog-1.jpg";
       SampleImages[1].src="../gx/hammel/dog-2.jpg";
       // Event handler called for onMouseOver event
       function mouseIn(input_status)
       {
               status = input_status;
               document.dog.src = SampleImages[1].src;
       }
       // Event handler called for onMouseOut event
       function mouseOut()
       {
               status="";
               document.dog.src = SampleImages[0].src;
       }
       // End of hidden script -->
       </SCRIPT>
       
   For this example you are safe in placing this bit of code inside the
   <HEAD> </HEAD> section of your HTML.
   
   The two event handlers call JavaScript functions.  The mouseIn()
   function is called to change the image when the mouse enters the image
   area.  As you see in the HREF tag the event handler associated with
   this function is the onMouseOver event.  This function has two lines.
   The first takes the text passed as an argument and places it on the
   status bar at the bottom of the browser.  The second line replaces the
   image referenced as "dog" by the second image in the SampleImages
   array. Pretty straight forward, don't you think?
   
   The second function, mouseOut(), is called when the mouse is moved out
   of the image area.  It, too, has two lines.  The first clears the
   status bar and the second places the image in the first element of the
   SampleImages array over the image currently in the object called
   "dog".  In this case, the SampleImages array's first element holds the
   same image source as the original image displayed in the IMG tag in
   our HTML source.
   
   A few things to note about the code: I used an array to hold the
   images I wanted to use for my rollover.  In this simple example I
   could just have easily used
   
                document.dog.src = "../gx/hammel/dog-1.jpg"
                                      
   instead.  If you use an array be sure to define the storage for the
   array objects.  I first defined the array with
   
                    SampleImages = new Array(numitems);
                                      
   I then defined the image storage for each element of the array with
   
                       SampleImages[0] = new Image();
                                      
   Of course this could be done in a loop, like with a for() statement.
   The definition of these objects with the "new" keyword causes
   JavaScript to load the image but not actually display it.  You could
   use these scripts to preload images to a page so that when subsequent
   pages were accessed the images could be pulled from cache immediately.
   
   The image object also contains a number of other properties, such as
   the BORDER width, image HEIGHT and WIDTH, and the VSPACE attribute for
   setting the vertical space around the image.  By not specifying the
   HEIGHT and WIDTH for the document.dog object in the functions I have
   assumed the new image has the same dimensions as the old.  If this
   were not the case you might want to update the image dimensions in
   your functions as well.
   
   Well, that should get you started.  Image rollovers are kinda cool to
   play with and can add a little pizazz to an otherwise drap Web page,
   but be careful.  Like most of the neat toys on the Web, too much of
   anything can be annoying.
   ______________________________________________________________________
   
   
   Musings
   indent
   
SIGGRAPH 97 Notes

   For those that don't know, SIGGRAPH is the yearly conference on
   computer graphics sponsored by the ACM.  To be exact, SIGGRAPH is the
   Special Interest Group - Graphics of the ACM and the conference is an
   extension of that, but in the past few years this conference has grown
   into a major exposition where all the big names in the computer and
   entertainment industry show their latest wares.  This year the
   conference was held in Los Angeles.  It was also my inaguaration into
   this madhouse.
   
   I should tell you that what follows is not specifically Linux
   related.  I will try to associated what I saw or learned with Linux as
   much as possible, but in general Linux is not a powerhouse at
   SIGGRAPH,  In fact, with the exception of one technical course and a
   couple of engineers manning booths at the show, I didn't hear anyone
   talk about Linux.  We have some work ahead of us to get real notice.
   
   For me, SIGGRAPH lasted 4 days, Sunday through Wednesday, even though
   the conference actually ran for 6 days.  I went as my vacation (sick,
   isn't it) and after 4 days had been run so ragged I decided my last
   full day would do something quite and peaceful - so I went to
   Universal Studios.  SIGGRAPH, for those who've never been, is non-stop
   energy drain, both physically and mentally.
   
   My first day there I spent going through lines - at the airport, at
   the car rental (my god, what a mess), and at the conference
   registration booths.  I had preregistered and so I only needed to pick
   up my conference materials, but that took about 45 minutes.  Having
   not been to a conference of any kind since a trip to Interop back in
   1991, I was a bit disappointed to see no texts provided for the
   courses.  In fact, the courses weren't really courses, they were
   presentations in front of monster sized audiences.  I remember the
   Interop courses being a bit more personal, more like real classes.
   
   Although I got there late, I did managed to get into the Introductory
   class on OpenGL that was given by SGI staff members.  It was mostly a
   discussion on basic OpenGL syntax.  I did manage to wind up sitting
   right next to Bruce Peren's office mate at Pixar - a very nice fellow
   named Jim W. (my notes didn't include his last name - hope he doesn't
   get made at me).  That seemed strange until I found out that Pixar
   sends just about everyone to SIGGRAPH.  A few days later I saw Larry
   Gritz but didn't get a chance to talk to him.  Like most people at
   SIGGRAPH, he was in a hurry to get somewhere.
   
   The rest of the day I spent wondering around the LA convention center
   looking for where other classes and events would be held.  There was a
   career center downstairs where people could post resumes and companies
   posted job positions.  Xi Graphics had a posting there, but other than
   that I didn't see any Linux-related postings.  By the time I got back
   to my hotel it was about 9pm - and I had yet to eat that day.  One
   word of warning to future attendees:  take snacks!  Finding food can
   be hard and what you do find can be awful (at least in LA by the
   convention center) and you will need the enegy!  Being a running, I
   should have brought a few energy bars with me.  Well, thats a lesson
   learned.
   
   The next day I went to the Advanced OpenGL course, also taught by SGI
   staff.  This was a more interesting class to me, since it talked about
   techniques a bit more than just syntax.  There were some good
   discussions on using environment maps (mapping an image to surface),
   projecting textures, and billboarding.  This last one is a cool
   technique I wasn't aware of.  An image is mapped onto a planar surface
   and that surface is programmed to always face towards the viewer.  It
   is sort of like taking a photo of a tree, cutting away all of the
   photo except the tree, and pasting it to a popsicle stick.  The stick
   is then rotated so that the photo of the tree always faces you.  It
   simulates a 3D effect without all the overhead of huge polygon counts
   for a real tree.  This technique works well for scene objects that are
   in the distance but looses its effect up close.  You can see
   billboarding effects in many games.
   
   Another effect they covered was the creation of fire.  They used a
   noise function along with what are called "quad mappings" to blur
   regions of the noise.  They then added some turbulence and an absolute
   value
   
                                  [INLINE]
                                      
   function to create veins in the fire.  It turns out you can do
   something similar with the GIMP by using the solid noise filter,
   followed by some blurring and waves adjustments, and cleaned up with a
   combination of curves/color balance adjustments (for color), and
   sharpening (for details).
   
   When I got home I went to visit my sister and her kids and watched
   them play Super Mario Bros on their ... Sega?  Anyway, having just
   returned from SIGGRAPH I could see the effects they talked about in
   the advanced OpenGL course.  It was very enlightening.
   
   One of my reasons for going to the OpenGL courses was to get an idea
   for how multimedia applications could be built for Linux.  An
   alternative to an OpenGL based multimedia kit would be one based on
   VRML. I attended the VRML Demo SIG on Monday night and it had some
   very cool demos using VRML 2.0.  If based on CD-ROM this could be a
   very good cross platform environment for multimedia packages
   (edutainment, for example).  The current drawback is that the demos
   required 2.0 capable browsers, but there should any number of those
   showing up in the next year or so.  According to CGW (freebie that was
   dropped at my hotel room - very nice touch), Netscape 4.0 has the SGI
   Cosmo Player embedded in it now.  I haven't been able to get this to
   work yet, however.  Since I have a 2.0 kernel installed now I can try
   some of the other VRML browsers available.  Maybe I'll get to that
   next month.
   
                            -Top of next column-
                                      
                                      
                                      
   indent
   
    More Musings...
   
     GIMP Tip - 3D metal and plastic borders.
   
   [INLINE]
   On Tuesday I arrived 1/2 hour early to take the 3D Animation
   Workshop.  I was about 20th in line of 100 or so, but somehow managed
   to miss getting a little blue ticket.  Despite the people at the door
   having seen me there for 30 minutes waiting (before others had showed
   up) I still didn't get in.  I was very pissed.  This class was one of
   my prime reasons for my going to SIGGRAPH.  Hint:  if you get in line
   at SIGGRAPH, make sure you check with the people in front of you to
   see if you need to have some special form, ticket, or sacrificial
   offering to get in.
   
   My fallback course was the GUI/Multimedia class.  There really wasn't
   much multimedia discussion - mostly it covered how to design GUI
   intefaces.  Lots of design criteria which I'd learned by fire long
   ago.  When they finally did get around to multimedia they talked about
   the lack of standards and how most applications are reinventing GUI
   rules.  This was my assessment before going to the class, but it was
   nice to have it reinforced by someone who studies such things for a
   living.
   
   Next I skipped out to Mark Kilgard's OpenGL w/Windowing systems
   class.  Pretty good stuff.  Brian Paul talked about MesaGL a little as
   well as some portability issues.  Both are very nice guys - I chatted
   with them a bit after the class.  One thing Mark mentioned was that
   there arent' any toolkits specifically built with OpenGL, which makes
   sense.  There is an overhead in creating widgets using OpenGL that
   would make it unsuitable for most applications.  Instead, OpenGL is
   integrated into applications using some other toolkit, like Motif,
   XForms, or Tk, using a toolkit specific OpenGL-capable widget.
   
   Later on I stumbled into the Java3D class for a few minutes.  Looks
   interesting but I didn't get too many details.  Sun is saying a beta
   release of a sample implementation of the specification  is due out in
   December of 1997 but the course speakers said they hoped to have it
   out much sooner.  They also expect that since the specification is
   public and being openly developed that sample implementations from
   non-Sun sources are likely to show up before the Sun release.  Or at
   least they expect that - they didn't have any information on any
   specific implementations.  At this point I haven't heard of any Java3D
   announcements from my usual sources.
   
   I talked to a couple of recruiters at the career fair, mostly just to
   get a feel for what companies are looking for these days.  They
   mentioned that the best way people can avoid getting lost in the crowd
   of candidates at the fair is to submit resumes based on job postings
   from the corporate web sites.  If you go next year looking for work,
   check out some of the participating companies job listings before
   heading to the career fair.
   
   First day of the show for me was Wednesday.  It looked more like a
   cross between a theme park ride and a disco, especially when Intel
   rolled out their MMX "clean-room dancers".  SGI offered a 1/2 hour
   demo ride with their O2 systems.  Cute demo but really didn't give a
   good feel for what you were really buying.  After talking to some of
   the show staff and taking the demo ride I still don't know exactly
   what applications come with the stock O2 box.  The $4995 price offered
   to conference participants wasn't bad, however.  Certainly compares
   well with a comparably equipped PC running NT.  There is a
   freeware/shareward CD available for O2 developers according to one of
   the engineers I talked to, but I didn't see it.
   
   The SGI O2 demo showed me one thing which I had hoped I'd find out
   from the show:  how to create multimedia applications.  In fact, after
   the demo a White Paper was passed out explaining how the demo was put
   together.  Some items, like the networking that allowed real-time
   texture mapping of live video, are not really possible on Linux boxes
   with available software.  But most of the rest is:  OpenGL rendered in
   Motif widgets was used for the GUI and OpenGL and VRML were used for
   interactive 3D displays.  OpenGL is available commercially and with
   MesaGL.  Motif is available commercially. I'm not certain VRML is
   available for integration into applications via an API, but animation
   could be done using MPEG.  There are some MPEG API's, such as MpegTV's
   API.  ImageMagick's PlugIn distribution appears to have an MPEG
   library, but I don't know if it provides a decent enough API for
   commercial multimedia applications.
   
   After seeing the SGI demo and the VRML SIG demos I've changed my mind
   about VRML - its ready for prime time.  I wouldn't recommend it for
   network applications yet, at least not Internet based applications,
   but for private networks (such as kiosks) or CD-based multimedia
   applications it could offer some unique possibilities.
   
   Wacom was at the show and a few of the staff didn't get defensive when
   I brought up Linux (it all depends on how non-abrasively you bring up
   the subject). They were even quite apologetic about not having any
   info on which tablets were supported by XFree86.  They now have a pad
   that is actually a full-color flat screen - you simply draw on it like
   you do with the tablets.  Very cool, but currently runs > $2200.
   
   Cosmo Software (new division of SGI) staff were pleasant as well,
   mentioning that it might be possible to provide someone with the
   source to port the Cosmo Player to Linux.  The player (which plays
   VRML 2.0 scenes) is free for various other platforms.  I guess they
   just need someone to ask for it and provide some credentials to prove
   they could do a decent port.  Unfortunately, I'm not certain who to
   talk to about this.
   
   Huge crowds formed around the Apple booth right at the entrance.  One
   demo I caught caused an OS lockup, but for the most part people were
   quite excited about the products.  I don't know much about Mac's so
   didn't stay long.  However, like LInux, Mac is an underdog in the OS
   world and I can't help but hope they survive.
   
   The one thing about this trip that stood out for me was LA itself.  It
   was Hot.  Outside.  Inside.  In classes.  In the car.  In the hotel.
   Everywhere.  Hot. LA also has an ugly downtown compared to others I've
   seen.  It also apparently has very few restaurants anywhere near the
   Convention Center.  A 6 block walk in Colorado is no big deal, but a 6
   block walk in LA in August....*sigh*.  Food was a big problem for me.
   I hope the same problem doesn't exist in Orlando next year.
   
   
   [INLINE] submitted resumes based on job postings from their web sites.
   
   
   Resources The following links are just starting points for finding
   more information about computer graphics and multimedia in general for
   Linux systems. If you have some application specific information for
   me, I'll add them to my other pages or you can contact the maintainer
   of some other web site. I'll consider adding other general references
   here, but application or site specific information needs to go into
   one of the following general references and not listed here.
   
   Linux Graphics mini-Howto
   Unix Graphics Utilities
   Linux Multimedia Page
   
   Some of the Mailing Lists and Newsgroups I keep an eye on and where I
   get much of the information in this column:
   
   The Gimp User and Gimp Developer Mailing Lists.
   The IRTC-L discussion list
   comp.graphics.rendering.raytracing
   comp.graphics.rendering.renderman
   comp.graphics.api.opengl
   comp.os.linux.announce  [INLINE]
   
Future Directions

   Next month:
   I don't know yet.  Things are very hectic right now, but I'll think of
   something.  Thanks to everyone who has made suggestions in the past!
   I do keep all your suggestions, even if I haven't gotten around to all
   of them yet.
   
   Let me know what you'd like to hear about!
     _________________________________________________________________
   
                    Copyright © 1997, Michael J. Hammel
           Published in Issue 23 of Linux Gazette, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [LINK] Back Next 
     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                 GNU/Linux Benchmarking - Practical Aspects
                                      
                             by André D. Balsa 
                                      
                           v0.4, 26 November 1997
     _________________________________________________________________
   
   This is the second article in a series of 4 articles on GNU/Linux
   Benchmarking, to be published by the Linux Gazette. The first article
   presented some basic benchmarking concepts and analyzed the Whetstone
   benchmark in more detail. The present article deals with practical
   issues in GNU/Linux benchmarking: what benchmarks already exist, where
   to find them, what they effectively measure and how to run them. And
   if you are not happy with the available benchmarks, some guidelines to
   write your own. Also, an application benchmark (Linux kernel 2.0.0
   compilation) is analyzed in detail.
     _________________________________________________________________
   
1. The DOs and DON'Ts of GNU/Linux benchmarking

2. A roundup of benchmarks for Linux

3. Devising or writing a new Linux benchmark

4. An application benchmark: Linux 2.0.0 kernel compilation with gcc

     * 4.1 General benchmark features
     * 4.2 Benchmarking procedure
     * 4.3 Examining the results
       
5. Next month
     _________________________________________________________________
   
1. The DOs and DON'Ts of GNU/Linux benchmarking

   GNU/Linux is a great OS in terms of performance, and we can hope it
   will only get better over time. But that is a very vague statement: we
   need figures to prove it. What information can benchmarks effectively
   provide us with? What aspects of microcomputer performance can we
   measure under GNU/Linux?
   
   Kurt Fitzner reminded me of an old saying: "When performance is
   measured, performance increases."
   
   Let's list some general benchmarking rules (not necessarily in order
   of decreasing priority) that should be followed to obtain accurate and
   meaningful benchmarking data, resulting in real GNU/Linux performance
   gains:
    1. Use GPLed source code for the benchmarks, preferably easily
       available on the Net.
    2. Use standard tools. Avoid benchmarking tools that have been
       optimized for a specific system/equipment/architecture.
    3. Use Linux/Unix/Posix benchmarks. Mac, DOS and Windows benchmarks
       will not help much.
    4. Don't quote your results to three decimal figures. A resolution of
       0.1% is more than adequate. Precision of 1% is more than enough.
    5. Report your results in standard format/metric/units/report forms.
    6. Completely describe the configuration being tested.
    7. Don't include irrelevant data.
    8. If variance in results is significant, report alongside results;
       try to explain why this is so.
    9. Comparative benchmarking is more informative. When doing
       comparative benchmarking, modify a single test variable at a time.
       Report results for each combination.
   10. Decide beforehand what characteristic of a system you want to
       benchmark. Use the right tools to measure this characteristic.
   11. Check your results. Repeat each benchmark once or twice before
       publicly reporting your results.
   12. Don't set out to benchmark trying to prove that equipment A is
       better than equipment B; you may be in for a surprise...
   13. Avoid benchmarking one-of-a-kind or proprietary equipment. This
       may be very interesting for experimental purposes, but the
       information resulting from such benchmarks is absolutely useless
       to other Linux users.
   14. Share any meaningful information you may have come up with. If
       there is a lesson to be learned from the Linux style of
       development, it's that sharing information is paramount.
     _________________________________________________________________
   
2. A roundup of benchmarks for Linux

   These are some benchmarks I have collected over the Net. A few are
   Linux-specific, others are portable across a wide range of
   Unix-compatible systems, and some are even more generic.
     * UnixBench. A fundamental high-level Linux benchmark suite,
       Unixbench integrates CPU and file I/O tests, as well as system
       behaviour under various user loads. Originally written by staff
       members at BYTE magazine, it has been heavily modified by David C.
       Niemi.
     * BYTEmark as modified by Uwe Mayer. A CPU benchmark suite,
       reporting CPU/cache/memory , integer and floating-point
       performance. Again, this test originated at BYTE magazine. Uwe did
       the port to Linux, and recently improved the reporting part of the
       test.
     * Xengine by Kazuhiko Shutoh. This is a cute little X window
       tool/toy that basically reports on the speed with which a system
       will redraw a coloured bitmap on screen (a simulation of a four
       cycle engine). I like it because it is unpretentious while at the
       same time providing a useful measure of X server performance. It
       will also run at any resolution and pixel depth.
     * Whetstone. A floating point benchmark by Harold Curnow.
     * Xbench by Claus Gittinger. Xbench generates the famous xstone
       rating for Xserver performance comparisons.
     * XMark93. Like xbench, this is a script that uses X11's x11perf and
       computes an index (in Xmarks). It was written a few years later
       than xbench and IMHO provides a better metric for X server
       performance.
     * Webstone 2.01. An excellent tool for Web server performance
       testing. Although Webstone is copyight by Silicon Graphics, it's
       license allows free copying and examination of the source code.
     * Stream by John D. McCalpin. This program is based on the concept
       of "machine balance" (sustainable memory bandwidth vs. FPU
       performance). This has been found to be a central bottleneck for
       computer architectures in scientific applications.
     * Cachebench by Philip J. Mucci. By plotting memory access bandwidth
       vs. data size, this program will provide a wealth of benchmarking
       data on the memory subsystem (L1, L2 and main memory).
     * Bonnie by Tim Bray. A high-level synthetic benchmark, bonnie is
       useful for file I/O throughput benchmarking.
     * Iozone by Bill Norcott. Measures sequential file i/o throughput.
       The new 2.01 version supports raw devices and CD-ROM drives.
     * Netperf is copyright Hewlett-Packard. This is a sophisticated tool
       for network performance analysis. Compared to ttcp and ping, it
       verges on overkill. Source code is freely available.
     * Ttcp. A "classic" tool for network performance measurements, ttcp
       will measure the point-to-point bandwidth over a network
       connection.
     * Ping. Another ubiquitous tool for network performance
       measurements, ping will measure the latency of a network
       connection.
     * Perlbench by David Niemi. A small, portable benchmark written
       entirely in Perl.
     * Hdparm by Mark Lord. Hdparm's -t and -T options can be used to
       measure disk-to-memory (disk reads) transfer rates. Hdparm allows
       setting various EIDE disk parameters and is very useful for EIDE
       driver tuning. Some commands can also be used with SCSI disks.
     * Dga with b option. This is a small demo program for XFree's DGA
       extension, and I would never have looked at it were it not for
       Koen Gadeyne, who added the b command to dga. This command runs a
       small test of CPU/video memory bandwidth.
     * MDBNCH. This is a large ANSI-standard FORTRAN 77 program used as
       an application benchmark, written by Furio Ercolessi. It accesses
       a large data set in a very irregular pattern, generating misses in
       both the L1 and L2 caches.
     * Doom :-) Doom has a demo mode activated by running doom -timedemo
       demo3. Anton Ertl has setup a Web page listing results for various
       architectures/OS's.
       
   All the benchmarks listed above are available by ftp or http from the
   Linux Benchmarking Project server in the download directory:
   www.tux.org/pub/bench or from the Links page.
     _________________________________________________________________
   
3. Devising or writing a new Linux benchmark

   We have seen last month that (nearly) all benchmarks are based on
   either of two simple algorithms, or combinations/variations of these:
    1. Measuring the number of iterations of a given task executed over a
       fixed, predetermined time interval.
    2. Measuring the time needed for the execution of a fixed,
       predetermined number of iterations of a given task.
       
   We also saw that the Whetstone benchmark would use a combination of
   these two procedures to "calibrate" itself for optimum resolution,
   effectively providing a workaround for the low resolution timer
   available on PC type machines.
   
   Note that some newer benchmarks use new, exotic algorithms to estimate
   system performance, e.g. the Hint benchmark. I'll get back to Hint in
   a future article.
   
   Right now, let's see what algorithm 2 would look like:
   
     initialize loop_count
     
     start_time = time()
     
     repeat 
     
     benchmark_kernel()
     
     decrement loop_count
     
     until loop_count = 0
     
     duration = time() - start_time
     
     report_results()
     
   Here, time() is a system library call which returns, for example, the
   elapsed wall-clock time since the last system boot. Benchmark_kernel()
   is obviously exercising the system feature or characteristic we are
   trying to measure.
   
   Even this trivial benchmarking algorithm makes some basic assumptions
   about the system being tested and will report totally erroneous
   results if some precautions are not taken:
    1. If the benchmark kernel executes so quickly that the looping
       instructions take a significant percentage of total loop processor
       clock cycles to execute, results will be skewed. Preferably,
       benchmark_kernel() should have a duration of > 100 x duration of
       looping instructions.
    2. Depending on system hardware, one will have to adjust loop_count
       so that total length duration > 100 x clock resolution (for 1%
       bechmark precision) or 1000 x clock resolution (for 0.1% benchmark
       precision). On PC hardware, clock resolution is 10 ms.
    3. We mentionned above that we used a straightforward wall-clock
       time() function. If the system load is high and our benchmark gets
       only 3% of the CPU time, we will get completely erroneous results!
       And of course on a multi-user, pre-emptive, multi-tasking OS like
       GNU/Linux, it's impossible to guarantee exclusive use of the CPU
       by our benchmark.
       
   You can substitute the benchmark "kernel" with whatever computing task
   interests you more or comes closer to your specific benchmarking
   needs.
   
   Examples of such kernels would be:
     * For FPU performance measurements: a sampling of FPU operations.
     * Various calculations using matrices and/or vectors.
     * Any test accessing a peripheral i.e. disk or serial i/o.
       
   For good examples of actual C source code, see the UnixBench and
   Whetstone benchmark sources.
     _________________________________________________________________
   
4. An application benchmark: Linux 2.0.0 kernel compilation with gcc

   The more one gets to use and know GNU/Linux, and the more often one
   compiles the Linux kernel. Very quickly it becomes a habit: as soon as
   a new kernel version comes out, we download the tar.gz source file and
   recompile it a few times, fine-tuning the new features.
   
   This is the main reason for proposing kernel compilation as an
   application benchmark: it is a very common task for all GNU/Linux
   users. Note that the application that is being directly tested is not
   the Linux kernel itself, it's gcc. I guess most GNU/Linux users use
   gcc everyday.
   
   The Linux kernel is being used here as a (large) standard data set.
   Since this is a large program (gcc) with a wide variety of
   instructions, processing a large data set (the Linux kernel) with a
   wide variety of data structures, we assume it will exercise a good
   subset of OS functions like file I/O, swapping, etc and a good subset
   of the hardware too: CPU, memory, caches, hard disk, hard disk
   controller/driver combination, PCI or ISA I/O bus. Obviously this is
   not a test for X server performance, even if you launch the
   compilation from an xterm window! And the FPU is not exercised either
   (but we already tested our FPU with Whetstone, didn't we?). Now, I
   have noticed that test results are almost independent of hard disk
   performance, at least on the various systems I had available. The real
   bottleneck for this test is CPU/cache performance.
   
   Why specify the Linux kernel version 2.0.0 as our standard data set?
   Because it is widely available, as most GNU/Linux users have an old
   CD-ROM distribution with the Linux kernel 2.0.0 source, and also
   because it in quite near in terms of size and structure to present-day
   kernels. So it's not exactly an out-of-anybody's-hat data set: it's a
   typical real-world data set.
   
   Why not let users compile any Linux 2.x kernel and report results?
   Because then we wouldn't be able to compare results anymore. Aha you
   say, but what about the different gcc and libc versions in the various
   systems being tested? Answer: they are part of your GNU/Linux system
   and so also get their performance measured by this benchmark, and this
   is exactly the behaviour we want from an application benchmark. Of
   course, gcc and libc versions must be reported, just like CPU type,
   hard disk, total RAM, etc (see the Linux Benchmarking Toolkit Report
   Form).
   
4.1 General benchmark features

   Basically what goes on during a gcc kernel compilation (make zImage)
   is that:
    1. Gcc is loaded in memory,
    2. Gcc gets fed sequentially the various Linux kernel pieces that
       make up the kernel, and finally
    3. The linker is called to create the zImage file (a compressed image
       file of the Linux kernel).
       
   Step 2 is where most of the time is spent.
   
   This test is quite stable between different runs. It is also
   relatively insensitive to small loads (e.g. it can be run in an xterm
   window) and completes in less than 15 minutes on most recent machines.
   
4.2 Benchmarking procedure

  Getting the source.
  
   Do I really have to tell you where to get the kernel 2.0.0 source? OK,
   then: ftp://sunsite.unc.edu/pub/Linux/kernel/source/2.0.x or any of
   its mirrors, or any recent GNU/Linux CD-ROM set with a copy of
   sunsite.unc.edu. Download the 2.0.0 kernel, gunzip and untar under a
   test directory (tar zxvf linux-2.0.tar.gz will do the trick).
   
  Compiling and running
  
   Cd to the linux directory you just created and type make config. Press
   <Enter> to answer all questions with their default value. Now type
   make dep ; make clean ; sync ; time make zImage. Depending on your
   machine, you can go and have lunch or just an expresso. You can't
   (yet) blink and be done with it, even on a 600 MHz Alpha. By the way,
   if you are going to run this test on an Alpha, you will have to
   cross-compile the kernel targetting the i386 architecture so that your
   results are comparable to the more ubiquitous x86 machines.
   
4.3 Examining the results

  Example 1
  
   This is what I get on my test GNU/Linux box:
   
   186.90user 19.30system 3:40.75elapsed 93%CPU (0avgtext+0avgdata
   0maxresident)k
   
   0inputs+0outputs (147838major+170260minor)pagefaults 0swaps
   
   The most important figure here is the total elapsed time: 3 min 41 s
   (there is no need to report fractions of seconds).
   
  Hardware setup description
  
   If you were to complain that the above benchmark is useless without a
   description of the machine being tested, you'd be 100% correct! So,
   here is the LBT Report Form for this machine:
   
   LINUX BENCHMARKING TOOLKIT REPORT FORM
CPU

===

Vendor: AMD

Model: K6-200

Core clock:208 MHz (2.5 x 83MHz)

Motherboard vendor: ASUS

Mbd. model: P55T2P4

Mbd. chipset: Intel HX

Bus type: PCI

Bus clock: 41.5 MHz

Cache total: 512 Kb

Cache type/speed: Pipeline burst 6 ns

SMP (number of processors): 1

RAM

===

Total: 32 MB

Type: EDO SIMMs

Speed: 60 ns

Disk

====

Vendor: IBM

Model: IBM-DCAA-34430

Size: 4.3 GB

Interface: EIDE

Driver/Settings: Bus Master DMA mode 2

Video board

===========

Vendor: Generic S3

Model: Trio64-V2

Bus: PCI

Video RAM type: 60 ns EDO DRAM

Video RAM total: 2 MB

X server vendor: XFree86

X server version: 3.3

X server chipset choice: S3 accelerated

Resolution/vert. refresh rate: 1152x864 @ 70 Hz

Color depth: 16 bits

Kernel

======

Version: 2.0.29

Swap size: 64 MB

gcc

===

Version: 2.7.2.1

Options: -O2

libc version: 5.4.23

Test notes

==========

Very light system load.

RESULTS

========

Linux kernel 2.0.0 Compilation Time: 3 m 41 s

Whetstone Double Precision (FPU) INDEX: N/A

UnixBench 4.10 system INDEX: N/A

Xengine: N/A

BYTEmark integer INDEX: N/A

BYTEmark memory INDEX: N/A

Comments

=========

Just tested kernel 2.0.0 compilation.

  General comments
  
   Again, you will want to compare your results to those obtained on
   different machines/configurations. You will find some results on my
   Web site about 6x86s/Linux, in the November News page.
   
   This of course is pure GNU/Linux benchmarking, unless you want to go
   ahead and try to cross compile the Linux kernel on a Windows95 box!?
   ;-)
     _________________________________________________________________
   
5. Next month

   I expect that by next month you will have downloaded and tested a few
   benchmarks, or even started writing your own. So, in the next article:
   Collecting and Interpreting Linux Benchmarking Data
     * Correct uses of Linux benchmarking data.
     * Architecture specific issues of Linux benchmarks.
     * Benchmarking Linux SMP systems.
     * Examples of more complex benchmarks: UnixBench and BYTEmark.
     _________________________________________________________________
   
                      Copyright © 1997, André D. Balsa
         Published in Issue 23 of the Linux Gazette, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next 
     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                              Comfortable FTP
                                      
                               by Larry Ayers
     _________________________________________________________________
   
                                Introduction
                                      
   There are quite a few FTP clients available for Linux these days.
   Several of them are X programs, but why incur the overhead of running
   an X FTP client? Downloading a file is not a very interactive process.
   Usually an FTP download is a process running in the background, which
   just needs to be checked every now and then.
   
   On the other hand, using the basic command-line FTP program is not
   much fun unless you enjoy typing complete pathnames and filenames. A
   great improvement is the classic ncurses-based client NcFtp, written
   by Mike Gleason. This program has a well-designed bookmarking facility
   and supports the FTP "reget" command, which allows resumption of
   interrupted downloads. Unfortunately, file and directory names still
   must be typed in, though NcFtp does support shell-like completion of
   filenames in both local and remote directories.
   
   Recently I came across a new FTP client called cftp. It is being
   developed by Dieter Baron, and though it is still a relatively new
   program, it has been working superbly for me.
   
                                 About cftp
                                      
   Cfpt isn't a showy application. It uses the termcap library, which
   allows it to show a reverse-video modeline displaying the current host
   and directory, as well as the number of bytes transferred. Otherwise
   it resembles a ls -l listing of files in the remote directory. The
   default keybindings are fairly intuitive: d downloads a file, v views
   a remote file using your default pager, and the left and right arrow
   keys function like they do in the Lynx text-mode web-browser: the left
   arrow-key takes you back to the previous directory, and the right
   arrow-key descends into the subdirectory under the cursor. The other
   key-bindings (as well as user options) can be viewed during a session
   by typing :help. The colon as a prefix to a command will be familiar
   to anyone who has used the vi editor or one its clones. Vi and Emacs
   motion-keys can also be used instead of the arrow-keys.
   
   What impressed me was the quickness with which the program starts up
   and makes the connection; before you know it a directory listing is
   displayed. This is a small and efficient little program which
   nevertheless has convenient keyboard commands. It's just the thing for
   making a quick check of an FTP site, perhaps reading a few *.lsm or
   README files, then pressing q which tells cftp to first log off, then
   quit. Directory listings displayed during a session are cached in
   memory, so returning to a previously-viewed directory is
   near-instantaneous.
   
   Many FTP programs are in effect front-ends for the command-line FTP
   utility, just as many mail clients use sendmail to do the actual
   mail-handling. In contrast, cftp uses its own built-in FTP routines;
   this may be one reason for its speed. Instead of passing an FTP
   command through a GUI layer before handing it to the actual FTP
   executable, cftp is talking directly with the remote server.
   
                         Aliases and Configuration
                                      
   There are two files which cftp reads when starting up, ~/.cftprc and
   ~/.netrc. The ~/.cftprc file can contain personal changes to default
   settings, such as keybindings. Aliases for oft-visited sites can be
   entered into this file as well. The line
   
   alias sun ftp://sunsite.unc.edu/pub/Linux/Incoming
   
   enables quick access to the site by merely typing cftp sun.
   
   The ~/.netrc file is used by the default FTP program, as well as the
   FTP facilities provided by GNU Emacs' dired and XEmacs' EFS. Cftp
   refers to this file as well. An entry like this:
   
   default login anonymous password [your e-mail address]
   
   will save typing login info for sites which allow anonymous access,
   and if you access a site for which you have a username and password,
   lines like these:
machine [hostname] login [login-id] password [password]
macdef init cd /[directory to change to]

   will speed up accessing the site.
   
                              New Enhancements
                                      
   When I began this review version 0.7 was the latest version; since
   then version 0.8 has been released, which contains several new
   features:
     * In this version "putting" or uploading files to a remote site is
       supported.
     * Directory listings can now be sorted by date as well as by name.
     * A new option is a beep when a download is completed. This is handy
       when a session is running in the background or on another
       desk-top.
     _________________________________________________________________
   
                                 Conclusion
                                      
   As I write this cftp-0.8.tar.gz is the current version; the latest
   release can be found at the cftp home FTP site, or via the WWW at this
   site.
   
   I enjoyed trying this small application and find myself using it
   often. It's a small download and should compile easily if you have
   libtermcap installed. If you do try it, let Deiter Baron know what you
   think of it.
     _________________________________________________________________
   
                       Copyright © 1997, Larry Ayers
           Published in Issue 23 of Linux Gazette, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next 
     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                                   TkMan
                                      
                               by Larry Ayers
     _________________________________________________________________
   
                                Introduction
                                      
   The traditional form of unix documentation is the manual-page system,
   which uses the man command in conjunction with the Groff text
   formatter to display manual pages (with your default pager) on a
   terminal screen. This system is rather long in the tooth, but is still
   in widespread use because it both works well and doesn't require a
   windowing system. The man-page directory structure (with a directory
   corresponding to each directory of executables) is pretty well
   standardized, ensuring that when new software is installed the
   corresponding man-page(s) have a place waiting for them in the
   hierarchy.
   
   For the past couple of years Thomas Phelps, of the University of
   California at Berkeley, has been writing and rewriting a Tcl/Tk based
   man-page reader called TkMan. As John Ousterhout has released the
   successive versions of Tcl and Tk TkMan has been updated to make use
   of the expanded capabilities of the two toolkits. Soon after the
   release of Tcl/Tk 8.0 this past August, TkMan 2.0 was released; it's a
   major release with several new features, thus this review.
   
                         Features and Capabilities
                                      
   TkMan is a super-charged reader which can access and search your
   man-pages in a variety of useful ways, and then display them in a
   nicely-formatted and very configurable fashion. Here is a sampling of
   what TkMan can do:
     * Any man-page mentioned in another page serves as a hyper-text
       link, giving man-page reading something of the flavor of HTML
       browsing.
     * The section headers of a page can be collapsed into an outline,
       making it easy to get a feel for the contents and organization of
       the page.
     * Hyper-linked listings of each category of man-page (such as User
       Commands or Games), as well as a listing of new and recently added
       pages.
     * A listing of often-accessed pages can be created, and "virtual
       volumes" of pages can be set up, if you'd like to have several
       scattered pages accessible as a new volume or category.
     * Integration with the apropos and whatis commands.
     * There is an entry field in the main window which allows you to
       enter text-strings or regular expressions and search for them in
       the displayed page.
     * If you have the Glimpse indexing and search facility installed,
       TkMan can use its services for powerful searches of man-page text.
     * If you are either bored or in the mood for a little aleatory
       learning, there is a menu-button which will cause a random
       man-page to be displayed.
     * When starting up, TkMan reports on any faults it finds in your
       man-page and man-path set-up.
     * Configurable display colors and fonts.
       
   It is all too easy to end up with superfluous copies of man-pages on a
   Linux system. If your man-pages are gzipped, an upgrade to a new
   version of a program will install the new page, but the new one won't
   over-write the old because the old one has the .gz suffix, and thus
   the filename is different. TkMan offers a means of keeping track of
   duplicate man-pages; wnen a page is displayed, the title of the page
   in the menu-bar will have drop-down entries showing the paths of any
   other pages with the same name. Selecting one of these will load the
   page, and if it's an older version or just an exact duplicate it can
   be deleted. Here's a screenshot of a typical window:
   
   TkMan Screenshot
   
   This screenshot shows a man-page in its "folded" state; the
   right-pointing triangles are sections with hidden text. A mouse-click
   will expand them.
     _________________________________________________________________
   
                                Installation
                                      
   The latest version of TkMan relies on Tcl8.0 and Tk8.0, so if you want
   to try it out this may be a good time to upgrade. Recent versions of
   Tcl/Tk compile easily "out-of-the-box", so this shouldn't present too
   much of a problem. Unfortunately, especially if you've recently
   compiled and installed the 8.0 versions (and deleted the source),
   TkMan needs one patch to be applied to one of the Tk8.0 source files
   in order to function. The Tk source then needs to be recompiled.
   Thomas Phelps attempted to convince the Tk developers to include his
   patch in the distribution, but was unsuccessful. The patch adds
   outlining to the Tk text display functions. I've run several other
   applications which rely on Tk8.0 and the patch so far hasn't caused
   any problems.
   
   TkMan also depends on the services provided by PolyglotMan (formerly
   Rman), also written by Thomas Phelps. PolyglotMan is a separate
   program which can reverse-compile or translate man-pages from their
   native Nroff or Groff format to a variety of other formats, such as
   HTML, SGML, LaTeX, TkMan's native format, and the Perl pod format,
   among others. This should be compiled and installed first, as the
   TkMan makefile needs to contain PolyglotMan's path.
   
   TkMan is entirely a Tcl/Tk program, so it doesn't need to be compiled.
   The makefile instead rewrites several of the Tcl files, adapting them
   to your system's paths, before copying them to (by default)
   /usr/local. The makefile is well-commented and easy to adapt to your
   system.
   
                                Availability
                                      
   The current versions of both TkMan and PolyglotMan can be downloaded
   from the home site.
     _________________________________________________________________
   
                                Observations
                                      
   TkMan isn't the sort of man-page reader you'd want to fire up just to
   check the syntax of a command, but if you're needing to refer to
   several man-pages in a session it can be a great convenience. A
   history of pages you have viewed is stored as you work, and it can be
   accessed from a dynamically updated drop-down menu. The overview of
   all man-pages in a section can be interesting, too. It's easy to
   forget just how many of these pages there are, and sometimes just
   seeing the title of a program or command in the listing can spark
   curiousity. It's easy to get in the habit of using just a small subset
   of a command's capabilities; several times I've noticed a page listed
   for a command I've used frequently but never thought to investigate.
   Even more times I've seen listings for programs I long ago deleted!
   
   There are probably more features in TkMan than most people will ever
   use, but this increases the odds that the one which suits you is
   included. This seems to be a very high-quality program, and it will
   run on just about any flavor of unix out there.
     _________________________________________________________________
   
                       Copyright © 1997, Larry Ayers
           Published in Issue 23 of Linux Gazette, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [LINK] Back Next 
     _________________________________________________________________
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                     Processes on Linux and Windows NT
                                      
                     By Glen Flower, glenf@eis.net.au 
     _________________________________________________________________
   
        Introduction
            Virtual Memory
            Process Image
            User and Group Privileges
            Multitasking
            Multiprocessing
       
        Process Context
            Threads
            Scheduling
            Mutual Exclusion and Synchronisation
            Timers
       
        Communication Between Processes
            A Closer Look at Processes on the Linux Operating System
            Bibliography
     _________________________________________________________________
   
                       Copyright © 1997, Glen Flower
         Published in Issue 23 of the Linux Gazette, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next 
     _________________________________________________________________
   
                                      
                                      
   Bibliography
        The Linux Kernel : David A Rusling, Linux Documentation Project.
            Linux Programming Guide : Linux Documentation Project.
            Kernel Hacker's Guide : Linux Documentation Project.
            Pthreads posix threads html pages
            Inside Windows NT, Helen Custer, Microsoft Press.
            Readings on Microsoft Windows and WOSA, Microsoft Press.
            Programming Windows NT Unleashed: Hamilton, Williams.
            Operating Systems : William Stallings.
            The Magic Garden Explained : Goodheart, Cox.
            Windows NT Magazine : July 1997 : The NT Scheduler.
            Linux Journal : April 1997 : Threads Programming, Martin
            McCarthy.
            Linux man pages for : ps, vmstat, fuser, kill, procinfo,
            procmeter, free, readprofile, profil, nice, renice, pstree,
            top.
            Linux source code.
            Lecture notes for 85349 Operating Systems : David Jones /
            Steve Smith, CQU
                      
                                                             [LINK][LINK]
       
    Process Context
   
    Each time a process is removed from access to the processor,
   sufficient information on its current operating state must be stored
   such that when it is again scheduled to run on the processor it can
   resume its operation from an identical position. This operational
   state data is known as its context and the act of removing the
   process's thread of execution from the processor (and replacing it
   with another) is known as a process switch or context switch.
   
    The distinction is made here between the condition where a process is
   removed from the processor completely and is replaced by another
   process (a process switch) and the case where the process state is
   stored while execution is interrupted temporarily (a context switch).
   Note that a process switch performs a superset of the operations
   required for the context switch. The latter case may be when an
   external interrupt is serviced or when a system call necessitates a
   switch from user mode to system mode. In the case of the process
   switch much more information must be saved in order to later restore
   the process context than in the second case where the process remains
   resident in memory while it's thread of execution is interrupted.
   
    The context of a process includes its address space, stack space,
   virtual address space, register set image (e.g. Program Counter (PC),
   Stack Pointer (SP), Instruction Register (IR), Program Status Word
   (PSW) and other general processor registers), updating profiling or
   accounting information, making a snapshot image of its associated
   kernel data structures and updating the current state of the process
   (waiting, ready, etc).
   
    This state information is saved in the process's process control
   block which is then moved to the appropriate scheduling queue. The new
   process is moved to the CPU by copying the PCB info into the
   appropriate locations (e.g. the program counter is loaded with the
   address of the next instruction to execute).
   Linux
       
   
       
   Windows NT
       
   Each process's context is described by a task_struct structure. The
       task_struct holds data such as the scheduling policy, scheduler
       priority, real time priority, processor allowed time counter,
       processor registers, file handles (files_struct), virtual memory
       (mm_struct).
       
   
       
   The kernel maintains a view of a process or thread known as a kernel
       process object or kernel thread object respectively. These contain
       just the information the kernel needs to effectively switch
       between processes or threads.
       
    When a process switch is made the scheduler saves the process's
       task_struct and replaces the current tasks pointer with a pointer
       to the new process's task_struct, restoring its memory access and
       register context. This may be assisted by hardware.
       
   
       
    The kernel makes a context switch by pushing context information onto
       the current kernel mode stack, for a process it also saves the
       address of it's page table directory so that it's address space is
       maintained.
       
   
   
   
                                                       [LINK][LINK][LINK]
                                                                         
   User and Group Privileges
   
    Each process has some form of associated Process Identifier, (PID)
   through which it may be manipulated. The process also carries the User
   Identifier (UID) of the person who initiated the process and will also
   have group identifier (GID).
   
    The UID is used to decide privilege to perform operations on
   resources such as files. Processes will normally belong to one or more
   process groups. A group identifier (GID) is used by the kernel to
   identify privileges allocated to a group of users and hence their
   created processes. Groups allow subsets of the available privileged
   operations (such as granting of access to files, printers, ability to
   create directories) to be restricted to members of a particular group
   only, with non members of the group being excluded from performing
   those operations.
   
   
   Linux   Windows NT
   On a Unix derivative system such as Linux the PID, UID and GID
   identifiers equate to simple integers which are associated with
   processors as part of their Process Control Block.   A process handle
   is used for the process identifier. A process handle is a special case
   of an Object handle, where object handles may reference files, devices
   and processes.
   
   
   On Unix processes maintain a parent-child relationship where the
   process that initiates a sub process becomes a parent to it?s child
   via a fork and optional exec operation to first clone the parent
   process and then replace it with a new executable process image. Due
   to this relationship it is possible to terminate all child processes
   by sending a KILL signal to the parent. All of the processes in the
   system are accessed via a doubly linked list whose root is the init
   process?s task_struct data structure.
   
       Windows NT processes do not maintain a parent-child relationship.
   Instead a process maintains an Object table to hold handles of other
   processes.
   
   
   
   When a new process is created it inherits all object handles from its
   creator that were previously marked with the inheritance attribute.
   
   
   Access to resources is decided as a result of the combination of
   resource defined permissions and a combination of the UID, GID (or
   effective UID and GID) under which a process is running. The owner of
   a resource or the administrator may grant access to a user or group of
   users.   The NT Object Manager attaches an access token to a process
   which is checked against a resource's permissions to decide what
   granted access rights the process is allowed. The owner of a resource
   or the administrator may grant access permissions to a user or group
   of users.
   
   Example : a Linux device may be allocated the bitmask permissions of
   crwxr-x---, may be owned by the root user (UID=0) and be allocated to
   the admin group. The allocated permissions of the device indicate that
   a process operating for the root user will have read, write and
   execute permissions on the device. A process operating with an
   effective GID of the admin group will have read and execute
   permissions, with other users being prevented from carrying out any
   operations on the device.
   
                                                       [LINK][LINK][LINK]
                                                                         
   
   Introduction to Processes
   
   When a developer writes, compiles and links a programme it may be
   stored on a computer disk as a file in the disk file system. This file
   is created in a predefined format that the operating system or
   operating system shell will recognise as an executable programme.
   
    When a programme is run it is instantiated in memory, taking up
   system resources such as memory for data structures, file descriptors
   and providing at least one thread of execution which defines the
   current state and subsequent required operations for the process. The
   current executing program, or process, has total use of the
   microprocessor while in it's run state. A process will use files
   within the filesystems and may access the physical devices in the
   system either directly or indirectly.
   
    A process may operate in one of two modes which are known as 'user'
   mode and 'system' mode (or kernel mode). A single process may switch
   between the two modes, i.e. they may be different phases of the same
   process. Processes defaulting to user mode include most application
   processes, these are executed within an isolated environment provided
   by the operating system such that multiple processes running on the
   same machine cannot interfere with each other's resources. A user
   processs switches to kernel mode when it makes a system call,
   generates an exception (fault) or when an interrupt occurs (e.g.
   system clock). At this point the kernel is executing on behalf of the
   process. At any one time during its execution a process runs in the
   context of itself and the kernel runs in the context of the currently
   running process. This is shown in Figure 1.
   
                      Logical view of a Linux process
                                      
   
   
   Processes operating in kernel mode are privileged and are granted
   access to all computer resources (such as all available memory) free
   of the restrictions applied to user mode processes. The distinction
   between a process in either user or kernel mode may be supported by
   the hardware which serves to enforce the privilege rule and so protect
   the computer system from undue damage or failure due to ill behaved
   user processes.
   
    Though the basic concepts are similar, different operating systems
   implement process management in different ways.
   Linux   Windows NT
   On the Linux operating system privileged services are largely
   implemented by a single monolithic kernel. The kernel provides the
   central services required to support the successful operation of the
   computer.
   
   
   
   The Linux kernel can also have a number of loadable modules which may
   serve to supplement its central functions e.g. by the addition of a
   new file system. As the kernel carries out a number of
   responsibilities within a single entity it is commonly known as a
   macrokernel architecture.   The Windows NT operating system is based
   on a derivative of a layered operating system (such as VAX VMS) and a
   true client/server operating (such as Mach) microkernel architecture,
   where the central kernel process carries out only the most basic tasks
   in the most efficient manner possible.
   
    Associated with the microkernel are a number of privileged processes
   collectively known as the Executive which operate in their own
   separate process subsystems. These includes (amongst others) a
   dedicated Process Manager, Object Manager and Virtual Memory manager
   to provide specialised services as required to support the
   establishment of processes and their resources. The operating system
   itself will execute largely in kernel mode. User mode processes will
   often need access to services which can only be accessed by privileged
   code operating in kernel mode. In this case they call a system
   function which causes a hardware 'trap' to occur, causing a context
   switch to system mode where the required operation can be carried out
   in a controlled manner by 'trusted' operating system functions before
   context switching back again to user mode.
   
    Every user process runs in its own address space (typically 3Gbytes
   on a 32 bit processor) isolated from the address space of other active
   processes. From the point of view of the individual process it also
   has complete access to the processor(s) of the machine on which it is
   running i.e. it has it's own virtual machine on which it runs, under
   the control of the operating system but independent from other
   processes.
   
   
                                      
                                      
                                                       [LINK][LINK][LINK]
                                                                         
   
   
   
   
   
                                                                         
                                                                         
   Communication Between Processes
   
    Processes operate within their own virtual address space and are
   protected by the operating system from interference by other
   processes. By default a user process cannot communicate with another
   process unless it makes use of secure, kernel managed mechanisms.
   There are many times when processes will need to share common
   resources or synchronise their actions. One possibility is to use
   threads, which by definition can share memory within a process. This
   option is not always possible (or wise) due to the many disadvantages
   which can be experienced with threads. Methods of passing messages or
   data between processes are therefore required.
   
    Linux supports the following methods of communication. System V IPC
   refers to the version of Unix in which the concepts noted below were
   first introduced.
   
   Signals
       
   Signals are used to signal asynchronous events between processes. A
   process may implement a signal handler to carry out required when an
   event occurs or may use the system default actions. Most signals can
   be ignored or blocked, though the KILL signal cannot be ignored and
   will result in a non clean process exit.
   UNIX pipes
       
   A pipe connects the standard output of one process to the standard
   input of another. They provide a method of one-way communication
   between processes in a parent-child relationship and for this reason
   may be called half duplex pipes.
   Named Pipes (FIFOs)
   
     Named pipes appear similar to regular pipes but are implemented as
   device special First In-First Out (FIFO) files in the file system. It
   is not necessary for processes to maintain a parent-child relationship
   for them to communicate via named pipes. Named pipes are persistent
   and may be reused after their initial setup.
   System V IPC Message Queues Message queues consist of a linked list
   within the kernel's addressing space. Messages are added to the queue
   sequentially and may be retrieved from the queue in several different
   ways.
   System V IPC Semaphores Semaphores are counters used to control access
   to shared resources by multiple processes. They are most often used as
   a locking mechanism to prevent processes from accessing a particular
   resource while another process is performing operations on it.
   Semaphores are implemented as sets, though a set may have a single
   member.
   System V IPC Shared Memory
   
     Shared memory is a mapping of an area of memory into the address
   space of more than one process. This is the fastest form of IPC as
   processes do not subsequently need access to kernel services in order
   to share data.
   Full-duplex pipes (STREAMS) STREAMS were introduced by AT&T and are
   used for character based I/O within the kernel and between it?s
   associated device drivers as a full duplex transfer path between
   processes. Internally pipes may be implemented as STREAMS.
   Remote Procedure Call (RPC) A network inter-process connection
   protocol based on Sun Microsystems' RPC standard.
   Networking sockets (Berkeley style) Sockets allow local or network
   connection between processes. Socket names are implemented within a
   domain. In the UNIX domain a socket is given a path name within the
   file system. Other processes may use that name to communicate.
   Windows NT inter-process communication and synchronisation facilities
   include the following :
   
   Events or Event Pairs Event handles may be inherited, passed on
   creation or duplicated for a process. Event handles may optionally
   have names and are signalled using the SetEvent call.
   Anonymous Pipes Used primarily for communication between related
   processes. Anonymous pipes cannot be used over a network.
   Named Pipes (FIFOs) Named pipes are similar to anonymous pipes but may
   be referenced by name rather than handle, may be used over a network
   and can use asynchronous, overlapped I/O.
   Semaphores Like Linux, Windows NT semaphore objects are implemented as
   counters which act as guardians over a section of code or resource.
   Shared Memory A section object is a Win32 subsystem object which is
   made available as a file mapping object which two or more processes
   may share. One thread creates the section object and other threads
   obtain handles to it.
   Remote Procedure Calls (RPCs) An implementation of the Distributed
   Computing Environment (DCE) standard for calling processes over a
   network.
   Local Procedure Calls (LPCs) A facility similar in usage to RPC but in
   fact being a cut down version that can act only on a local computer to
   perform efficient message passing between client/server processes
   using kernel provided mechanisms. There are three basic choices :
    i. Messages may be passed into a server port objects message queue -
       used for small messages.
   ii. Messages are passed via a shared memory object.
   iii. Quick LPC is used by portions of the Win32 subsystem to achieve
       minimum overhead and maximum speed.
       
   STREAMS An implementation of the Unix System V driver environment used
   in networking.
   
   
   
                                                       [LINK][LINK][LINK]
                                                                         
   
   A Closer Look at Processes on the Linux Operating System
   
    On Linux there are a number of utilities which allow the System
   Administrator to examine the status of processes and to adjust their
   relative priorities or change their operational status. Some of these
   capabilities can be demonstrated by examining one programme available
   for the Linux OS : the Apache httpd daemon : a freely available web
   server. In the following prints of screen outputs some columns have
   been ommitted where they do not affect the demonstration being given.
   
    From the following it can be seen that the size of the http daemon is
   142699 bytes on the disk. Within the ELF file there are 108786 bytes
   of code, 4796 bytes of initialised data and 19015 bytes of
   uninitialiased data.
   
    orion-1:# ls -l httpd
   
    -rwxr-x--- 1 root root 142699 Oct 5 1996 httpd*
   
    orion-1:# size httpd
   
                       text Data bss dec hex filename
                 108786  4796  19015  132597  205f5  httpd
                                      
   Performing an object dump of the file shows that the code section is
   offset within the file and starts at hexadecimal address 0x1ce0, read
   only data starts at 0x16238, other data at 0x1a9e8 and uninitialised
   data at 0x1bcb0. There is a table of debugging symbols at 0x1bcb0 :
   
    orion-1:# objdump --headers httpd
   
   
   
   httpd: file format elf32-i386
   
    Sections: < Some sections excluded for clarity >
        Idx Name Size VMA LMA File off Algn
            0 .interp 00000013 080000d0 080000d0 000000d4 2**0
            CONTENTS, ALLOC, LOAD, READONLY, DATA
            8 .text 00014544 08001ce0 08001ce0 00001ce0 2**4
            CONTENTS, ALLOC, LOAD, READONLY, CODE
            10 .rodata 000047ac 08016238 08016238 00016238 2**2
            CONTENTS, ALLOC, LOAD, READONLY, DATA
            11 .data 00001050 0801b9e8 0801b9e8 0001a9e8 2**2
            CONTENTS, ALLOC, LOAD, DATA
            16 .bss 00004a47 0801ccb0 0801ccb0 0001bcb0 2**4
            ALLOC
            17 .stab 000004f8 00000000 00000000 0001bcb0 2**2
            CONTENTS, READONLY, DEBUGGING
            
   The http daemon utilises functions from the standard 'C' library,
   linked as a dynamic linked library (the 'so' stands for 'shared
   object') :
   
    orion-1:# ldd -r httpd
   
     libc.so.5 => /usr/local/lib/libc.so.5 (0x4000a0)
   
   The daemon is started at system boot time and was sleeping (S) when
   its status was checked, it is consuming very little CPU time :
   
    orion-1:# ps -fc | grep httpd
   
    PID TTY STAT TIME COMMAND
   
   90 ? S 0:00 httpd
   
    A printout of the tree of all processes running on the computer and
   their interrelationships shows that the httpd has init as its parent
   process, this is typical of a Unix daemon process. It has also created
   three child processes which it now controls, presumably to listen for
   http connections.
   
    orion-1:# pstree
                   init-+-4*[agetty]
                      |-bash--script--script--bash--script--script--bash-
                      -pstree
                      |-bash
                      |-crond
                      |-gpm
                      |-httpd--3*[httpd]
                      |-inetd
                      |-kflushd
                      |-klogd
                      |-kswapd
                      |-lpd
                      |-rpc.mountd
                      |-rpc.nfsd
                      |-rpc.portmap
                      |-sendmail
                      |-syslogd
                      `-update
                      
   This is confirmed by examining a few of the processes running in more
   detail. The init process has a Process ID (PID) of 1. It can be seen
   that the parent PID of the httpd is 1 as expected.
   
    It can be seen that the resident memory footprint (Resident Set Size
   (RSS)) of the httpd process is 528 kilobytes whereas its overall size
   in virtual memory is 1012 Mb. It can be seen that the process runs
   with a User ID of 0 (owned by the administrator (root)) and that it is
   running at the default priority of 0 (-20 being maximum real-time and
   20 being the lowest priority). The SW< status for the kernel swap
   daemon (kswapd) process shows that it is sleeping, has no resident
   pages and has a priority less than 0.
   
    orion-1:# ps -cl1,2,3,90
   
    F UID PID PPID PRI NI SIZE RSS WCHAN STAT TTY TIME COMMAND
   
   100 0 1 0 0 0 844 328 c01115c9 S ? 0:03 init [5]
   
   40 0 2 1 0 0 0 0 c0111a38 SW ? 0:00 (kflushd)
   
   40 0 3 1 -12 -12 0 0 c0111a38 SW< ? 0:00 (kswapd)
   
   140 0 90 1 0 0 1012 528 c0119272 S ? 0:00 httpd
   
    Looking at the virtual memory performances of the process it can be
   seen that the httpd has had 23 major page faults where a page fault
   represents an action to load a page of text from disk or buffer cache.
   The text (code) resident set size (TRS) is 24 kilobytes which suggests
   a code page size of 1024 bytes when viewed in association with the
   page fault number. The Data Resident Size is 108 kilobytes, giving a
   total SIZE of 132 kilobytes. The process shares 115 kilobytes with
   other processes (this may represent the standard 'C' shared library).
   
    orion-1:# ps -cmp1,2,3,90
   
   
   PID MAJFLT MINFLT TRS DRS SIZE SWAP RSS SHRD COMMAND
   
                                     2
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
   kflushd
   
                                     3
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
   kswapd
   
                                     1
                                      
                                    206
                                      
                                     49
                                      
                                     5
                                      
                                     77
                                      
                                     82
                                      
                                     0
                                      
                                     82
                                      
                                     65
                                      
   init
   
                                     90
                                      
                                     23
                                      
                                     51
                                      
                                     24
                                      
                                    108
                                      
                                    132
                                      
                                     0
                                      
                                    132
                                      
                                    115
                                      
   httpd
   
   The system administrator can re-prioritise the httpd process by
   changing it's NICE level. Here the priority of process 90 (httpd) is
   made higher by 10. Only the administrator can change priorities in a
   negative direction as shown. This prevents inexperienced users from
   overloading the CPU and also protects the system from hackers.
   
    orion-1:# renice -10 90
   
    90: old priority 0, new priority -10
   
    The new priority level can now be seen, although on this system the
   httpd is idle, receiving no web access requests so it would not
   consume much more CPU.
   
   orion-1:# ps -cl
   
   
   UID PID PRI PPID NI SIZE RSS STAT TIME COMMAND
   
                                     0
                                      
                                     1
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                                                      844
                                                                         
                                                                      328
                                                                         
   S 0:03 init [5]
   
                                     0
                                      
                                     2
                                      
                                     0
                                      
                                     1
                                      
                                     0
                                      
                                                                        0
                                                                         
                                                                        0
                                                                         
   SW 0:00 (kflushd)
   
                                     0
                                      
                                     3
                                      
                                    -12
                                      
                                     1
                                      
                                    -12
                                      
                                                                        0
                                                                         
                                                                        0
                                                                         
   SW< 0:00 (kswapd)
   
                                     0
                                      
                                     90
                                      
                                    -10
                                      
                                     1
                                      
                                    -10
                                      
                                                                     1012
                                                                         
                                                                      528
                                                                         
   S < 0:00 httpd
   
   The system is now loaded somewhat by running some CPU intensive shell
   scripts. The virtual memory statistics of the computer are examined
   every 5 seconds for five iterations.
   
    The procs field shows that on average 2 processes are waiting for CPU
   run time (r) and on iteration 3 two processes are in uninterruptable
   sleep. There is no swapping activity going on as the processes are
   small enough to be fully resident in memory.
   
    There is however I/O activity as blocks of data are brought in (bi)
   and sent out (bo) to I/O devices. The 'system' fields show that many
   interrupts are occurring per second (in) as well as many context
   switches (cs). The first iteration gives the average history since the
   last system reboot, whereas the subsequent four readings are for time
   now. It can be seen that the CPU is never idle (id) and is spending
   around 35% of its time in user mode and 65% of its time performing
   privileged operations in system mode.
   
    This report is consistent with the known operations being performed :
   I/O intensive disk reads : the Linux 'find' command searching the
   disk.
   
    orion-1:# vmstat 5 5
   
                                   procs
                                      
                                   memory
                                      
                                    swap
                                      
                                     io
                                      
                                   system
                                      
                                    cpu
                                      
   r b w swpd free buf si so bi bo in cs us sy id
   
                                     2
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     10
                                      
                                     8
                                      
                                    133
                                      
                                     34
                                      
                                     6
                                      
                                     8
                                      
                                     86
                                      
                                     2
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                    614
                                      
                                     11
                                      
                                    737
                                      
                                    1234
                                      
                                     32
                                      
                                     68
                                      
                                     0
                                      
                                     1
                                      
                                     2
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                    100
                                      
   129
   
                                    435
                                      
                                    366
                                      
                                     40
                                      
                                     60
                                      
                                     0
                                      
                                     2
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                    202
                                      
                                     26
                                      
                                    375
                                      
                                    455
                                      
                                     33
                                      
                                     67
                                      
                                     0
                                      
                                     2
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                     0
                                      
                                    230
                                      
                                     0
                                      
                                    331
                                      
                                    472
                                      
                                     31
                                      
                                     69
                                      
                                     0
                                      
   
   
    It is possible to probe the Linux kernel and find which operations
   are consuming the most CPU load. When this is done it is seen that the
   kernel is spending most of it's time dealing with the directory cache,
   file system and writing to the console. The system scheduling process
   is only the twentieth most active process on the list.
   
    To be able to read the profiling information from the kernel it must
   first be compiled with profiling enabled.
   
    orion-1:# readprofile | sort -nr | head -20
   
   
   CLK_TCK Function Normalised load
   67649 total
   
                                                                   0.0858
                                                                         
   7796 d_lookup
   
                                                                  54.1389
                                                                         
   5425 ext2_readdir
   
                                                                   3.5319
                                                                         
   5034 scrup
   
                                                                   7.8168
                                                                         
   4573 filldir
   
                                                                  14.8474
                                                                         
   4481 find_inode
   
                                                                  86.1731
                                                                         
   2849 ext2_check_dir_entry
   
                                                                  15.8278
                                                                         
   2581 getname
   
                                                                   7.9660
                                                                         
   1885 getblk
   
                                                                   2.2440
                                                                         
   1665 sys_newlstat
   
                                                                   6.8238
                                                                         
   1546 lookup_dentry
   
                                                                   5.1533
                                                                         
   1542 do_con_write
   
                                                                   0.3119
                                                                         
   1425 get_hash_table
   
                                                                   9.6284
                                                                         
   1422 cp_new_stat
   
                                                                   4.5577
                                                                         
   1323 __namei
   
                                                                  10.3359
                                                                         
   1270 system_call
   
                                                                  19.8438
                                                                         
   1231 ext2_getblk
   
                                                                   2.2140
                                                                         
   1084 raw_scan_sector
   
                                                                   1.8951
                                                                         
   1077 sys_getdents
   
                                                                   3.0597
                                                                         
   973 schedule
   
                                                                   1.2102
                                                                         
   
   
   The Linux 'ps' command takes its information from the /proc
   virtual-file system (VFS) which is a disk image of the process
   structures as controlled by the kernel. Note that the VFS is a direct
   mirror of the kernel data structures and does not actually reside on
   disk, although it appears to do so when acessed with normal Linux
   commands.
   
   Looking directly at the httpd process in the /proc file system, all of
   the information given by the administrative tools can be obtained,
   though often in a less user friendly format. The following is a direct
   dump of the httpd status table, with comments added for explanation :
   
   orion-1:# cat /proc/90/status
        Name: httpd
            State: S (sleeping)
            Pid: 90 # Process ID
            PPid: 1 # Parent Process (init)
            Uid: 0 0 0 0 # User ID (root)
            Gid: 65535 65535 65535 65535 # Group ID
            VmSize: 1012 kB # Total virtual memory
            VmLck: 0 kB # Total locked
            VmRSS: 512 kB # Text Resident Set Size
            VmData: 276 kB # Virtual Memory Data size
            VmStk: 20 kB # Stack size
            VmExe: 108 kB # Executable
            VmLib: 576 kB # Library
            SigPnd: 00000000 # Signals pending
            SigBlk: 00000000 # Signals blocked
            SigIgn: 80000000 # Signals ignored
            SigCgt: 00006441 # Signals caught
       
   
   
   The following are all the signals recognised by the Linux operating
   system, they are enumerated starting at zero (i.e. SIGHUP is 0,
   SIGKILL is 9, etc) :
   
   orion-1:# fuser -l
        HUP INT QUIT ILL TRAP ABRT IOT BUS FPE KILL USR1 SEGV USR2 PIPE
            ALRM TERM STKFLT CHLD CONT STOP TSTP TTIN TTOU URG XCPU XFSZ
            VTALRM PROF WINCH IO PWR UNUSED
            
                                                       [LINK][LINK][LINK]
            
            
   Multiprocessing
   
   So far we have considered machines which have only a single processor
   (known as the Central Processor Unit). Becoming more common these days
   are multi-processor machines which may have a number of processors
   (for example four or thirty two) which may provide true concurrency to
   multiple tasks running on the machine. On these machines the scheduler
   will arrange for the execution of processes to occur in a manner
   selected to take maximum advantage of the available processing
   capacity. Asymmetric multiprocessing (ASMP) operating systems
   typically select one processor to run operating system code, with the
   other processors running user jobs. Problems with such systems include
   a lack of portability of the operating system to other platforms.
   Symmetric multiprocessing systems (SMPs), which include Linux, Sun's
   Solaris and Windows NT each allow the operating system to run on any
   or all of the available processors, sharing memory between them. The
   central unit for execution on such machines is the thread, with
   multiple threads of a single process having the possibility to be
   spread across multiple processors. The scheduling task on an SMP
   computer can become extremely complex.
   
                                                       [LINK][LINK][LINK]
                                                                         
   
     Multitasking
   
   It would be extremely inefficient for a single process to have
   complete use of the processor from the time of its start-up to the
   completion of its operations. One reason for this is that most
   processes must pause very often to wait for input such as data from
   I/O devices, keyboard input or disk accesses. In the simplest case
   therefore a large amount of useable CPU time would be wasted due to
   this blocking. This would result in a large overall time to carry out
   a number of independent tasks. The processor must also handle
   asynchronous software or hardware interrupts which may require high
   priority service for a short period, requiring the currently active
   process to be displaced from the processor while the interrupt is
   handled before normal processing can be resumed. Such interrupts may
   be caused by events such as an input buffer becoming full which, if
   not serviced in a timely manner could result in an unrecoverable loss
   of data.
   
   To increase throughput efficiency most modern operating systems
   implement a method to allow many processes to be available for running
   at any one time. Their access to the processor is interleaved and, as
   the speed of modern processors is high compared to slower I/O devices,
   it is possible to provide a pseudo real-time response to an active
   user of the system for any particular process when in reality many
   processes are being run. The total time to complete a number of tasks
   will also be less due to less time being wasted waiting for external
   inputs. Interrupt handling is facilitated as well as this round robin
   scheduling of normal processes.
   
   This procedure is known as Multitasking (or Multiprogramming) and its
   sequencing is controlled by an operating system service called the
   scheduler. Some operating systems (e.g. Windows 3.1) just rely on the
   process itself giving up the processor at regular intervals or when
   waiting on I/O. This approach is known as co-operative multitasking
   and it can have many problems as, if the process does not give up the
   CPU at the expected time failure can occur. In this case all other
   processes will be blocked and there will be no way for the operating
   system to gain control of the processor, most likely resulting in a
   system lockup or crash.
   
   A better approach, and that used in most operating systems designed
   for efficient multitasking is that of pre-emptive multitasking . In
   this case it is the operating system that decides which process gets
   access to the CPU. It can allocate CPU time to a process or remove the
   process from the CPU as required. Each candidate process gets access
   to the CPU for a short time (known as a quantum) based on their
   allocated priority, their process class and also their voluntary
   release of the processor as they wait for external input.
   
                                                                         
                                                                         
                                                       [LINK][LINK][LINK]
                                                                         
   
   
   
   
   
   
   
   
   
   
                                      
                                      
   Mutual Exclusion and Synchronisation
   
    Allowing multiple processes access to the same resources in a time
   sliced manner or potentially consecutively in the case of
   multiprocessor systems can cause many problems. This is due to the
   need to maintain data consistency, maintain true temporal dependencies
   and to ensure that each thread will properly release the resource as
   required when it has completed its action.
   
    Concurrent processes in multitasking and / or multiprocessing
   operating systems must deal with a number of potential problems
   
   
   
    Process starvation or indefinite postponement A low priority process
       never gets access to the processor due to the higher effective
   processor access of other processes. Solution is to cause processes to
          'age' or decline in priority as they use up CPU quanta.
    Process deadlock Two or more processes are competing for resources,
                          each blocking the other.
   Race Conditions The processing result depends on when and how fast two
                  or more processes complete their tasks.
                                      
   
   
   The data consistency and race condition problems may be addressed by
   the implementation of Mutual Exclusion and Synchronisation rules
   between processes whereas starvation is a function of the scheduler.
   
   There are a number of synchronisation primitives :
   
   
   
     Events A thread may wait for events such as the setting of a flag,
   integer, signal or presence of an object. Until that event occurs the
       thread will be blocked and will be removed from the run queue.
    Critical Sections These are areas of code which can only be accessed
                    by a single thread at any one time.
    Mutual Exclusions mutexes are objects that ensure that only a single
     thread has access to a protected variable or code at any one time.
     Semaphores These are similar to mutual exclusions but may include
      counters allowing only a specified number of threads access to a
                protected variable or code at any one time.
     Atomic operations This mechanism ensures that an non decomposable
   transaction is completed by a thread before access to the same atomic
        operation is granted to another thread. The thread may have
   non-interruptable access to the CPU until the operation is completed.
                                      
   
   
   Deadlock is a permanent blocking of a set of processes that either
   compute for system resources or communicate with each other [MAEK87].
   Deadlock may be addressed by mutual exclusion or by deadlock
   avoidance. Mutual exclusion prevents two threads accessing the same
   resource simultaneously. Deadlock avoidance can include initiation
   denial or allocation denial, both of which serve to eliminate the
   state required for deadlock before it arises.
   
    Both Linux and Windows NT solve these problems in different ways.
   Windows NT has functions which equate to all of the above instances.
   Both implement multiprocessor mutual exclusion mechanisms called spin
   locks which effectively stall the processor until a lock is achieved
   for a critical section.
   
                                                       [LINK][LINK][LINK]
                                                                         
   
   
   
   
   
                                                                         
                                                                         
   Process Image
   
    Executable files are stored in a defined format on the disk,
   different operating systems may have different definitions for the
   actual format but there are generally common elements in the way they
   are stored. A format commonly used on Unix systems such as Linux is
   called Extensible Linked Format (ELF). An ELF programme consists of an
   ELF header, a program header table, a number of sections and an
   optional section header table. The header contains all the information
   the kernel needs to create a process image (i.e. load the programme
   into memory and allocate resources to prepare it for execution).
   
   Programme code on a multitasking operating system must be re-entrant.
   This means it can be shared by multiple processes. To be re-entrant
   the code must not modify itself at any time and the data must be
   stored separately from the instruction text (such that each
   independent process can maintain its own data space).
   
    When a programme is loaded as a process it is allocated a section of
   virtual memory which forms its useable address space. Within this
   process image there are typically at least four elements :
   
   
    Program code (or text) The program instructions to be executed. Note
    that it is not necessary for the processor to read the totality of a
      process into physical memory when a program is run, instead by a
   procedure known as ?dynamic paging? the next block of instructions is
          loaded as required and may be shared between processes.
    Program data May be distinguished as initialised variables including
    external global and static variables, uninitialised variables (known
   as a bss area on Unix derivative systems). Data blocks are not shared
                       between processes by default.
     Stack A process will commonly have at least two last-in, first-out
   (LIFO) stacks, including a user stack for user mode and a kernel stack
                              for kernel mode.
    Process Control Block Information needed by the operating system to
                            control the process.
                                      
   
   
                                                       [LINK][LINK][LINK]
                                                                         
      Scheduling
   
   A scheduler is responsible for the coordination of the running of
   processes to manage their access to the system resources such that
   each candidate process gets a fair share of the available process
   time, with the utilisation of the CPU being maximised. The scheduler
   (dispatcher) must ensure that processes gain access to the CPU for a
   time relative to its designated priority and process class and that no
   process is starved of access to the CPU, no matter if it is the lowest
   priority task available.
   
    A process may choose to voluntarily give up it's use of the
   microprocessor when it must wait, usually for some system resource or
   for synchronisation with another process. Alternatively the scheduler
   may pre-emptively remove the thread or process from the CPU at the
   expiry of it's allocated time quantum. The scheduler chooses which is
   the most appropriate process to run next.
   
    Scheduling is an operation of the kernel, which defines the following
   process states :
   
   
   Linux   Windows NT
   Running : The process is the current system process and is on the CPU
   carrying out it's execution.    Running : The process (thread) is the
   currently active process on the CPU.
   Running : Ready to Run : The process is in a run queue ready to use
   the CPU when available.   Standby : The thread has been selected to
   run next by the processor, only one thread can be in this state.
   Waiting : interruptable : The process is waiting for a resource or
   event but signals are not blocked and it may be interrupted.   Ready :
   The thread is simply waiting to execute and is a candidate for
   selection by the scheduler for entering standby at the next scheduling
   cycle.
   Waiting : uninterruptable : The process is waiting for a resource or
   event but has disable signals such that it cannot be interrupted.
   Waiting : The thread is waiting for synchronisation events, it has
   been directed to suspend by the environment subsystem or is waiting on
   I/O.
   Stopped : The process has been stopped, usually by a SIGSTOP signal
   such as when performing debugging.
   
       Transition : The thread is ready to execute but the resources it
   needs are not available. (e.g. the thread's kernel stack is paged out
   of memory).
   Zombie : The process has completed and is ready to die, the scheduler
   has not yet detected this so it?s task_struct structure is still
   present.   Terminated : The thread has finished executing and the
   object manager decides whether the thread is deleted. If the executive
   has a pointer to the thread it may be reinitialised and reused.
   
   The scheduling of tasks on the different operating systems is similar,
   but each OS solves the problem in it's own way :
   
   
   Linux
       
   
       
   Windows NT
       
   Tasks have a priority which ranges from a setting of -20 to +20. The
       default priority of a task is 0 with -20 being the highest. Only
       the administrator can reset a process's priority to be less than
       0, but normal users can adjust priorities in the positive range.
       This is done using the 'renice' command, though internally Linux
       uses a time quantum counter (in 'jiffies') to record this in the
       task_struct.
       New processes inherit the priority of their parent.
       
   
       
   Threads have a priority which ranges from 1 to 31 with 8 being the
       user default and 31 being the highest. Priority 0 is reserved for
       system use. Only the administrator can set a processes priority to
       be above 15, normal users can set a process's priority in the 1 to
       15 range in a two step process by first setting the process class
       and then setting the relative priority within the class. This is
       done using the Task Manager.
       New processes inherit the priority of their creating process.
       
    Real time processes are supported. Any real time process will have
       higher priority than all non real-time processes.
       
       
       
   
       
   Processes having priorities between 16 and 31 are real-time processes
       which are members of the realtime class.
        time-critical and idle modifiers may move a dynamic thread's
       priority to the top or bottom of it's dynamic range respectively.
       
   Threads that have already received some CPU time will have lower
       priority than other of the same priority which have not.
       
   
       
   Non real-time threads may be boosted in priority should (e.g.) a
       blocked thread receive an event if was waiting for. This boost
       decays over time as the thread receives CPU time.
       
   
    The following diagram shows the state machine used for the Windows NT
       scheduler. From the above tables it can be seen that although the
       corresponding state for machine for Linux will be different it
       will be similar. Linux also has kernel mechanisms called bottom
       half handlers which are not covered here.
       
   
        [INLINE]
            
            
            
            
                                                       [LINK][LINK][LINK]
            
            
                                      
                                      
    Threads
   
    The majority of processes seen on operating systems today are single
   threaded, meaning there is a single path of execution within the
   process. Should a process have to perform many sub tasks during it's
   operation then a single threaded process would sequence these tasks in
   a serial manner, with each sub task being required to wait for the
   completion of the previous sub task before commencement. Such an
   arrangement can lead to great inefficiency in the use of the processor
   and in the apparent responsiveness of the computer.
   
   An example can illustrate the advantages of having multiple threads of
   execution as shown in the figure. Suppose a user wants to print a
   document, a user process can be initiated to accept input from the
   operator to select the print action and start the printing action.
   Should the user process be required to check for further user commands
   subsequent to initiating the print there are two options :
   
   (i) the process can stop the printing periodically, poll for user
   input, then continue printing, or
   
   (ii) wait until printing has completed before accepting user input.
   
   Either of these alternatives slow down printing and/or decrease
   responsiveness. By contrast a multi-threaded process can have many
   paths of execution. A multi-threaded application can delegate the
   print operation to a different thread of execution. The input thread
   and print thread then run in parallel until printing is completed.
   
   
        [INLINE]
       
    Each thread has access to the allocated resources within the process
   and can access global variables available to all threads. In a
   multi-threaded process each thread 'believes' it has independent
   access to its own 'virtual machine' with the scheduler being
   responsible for allocation of CPU quanta to threads to optimise
   throughput efficiency.
   
    Threads within the same task share resources such as file pointers
   and code segments. Swapping between threads within a process presents
   a much smaller overhead to the scheduler than swapping between
   processes. This is because less context related data must be saved to
   enable successful restoration of that context later. For this reason
   threads are often known as 'light weight processes' (LWPs) with normal
   processes being correspondingly known as heavyweight processes.
   Typically, when a thread context switch is performed, only the program
   counter and register set need to be saved in the PCB. Heavy-weight
   processes typically don?t share such resources so when heavy-weight
   processes context switch, all this additional info must be saved.
   
    Although threads have many advantages as described above, they also
   have disadvantages, one of these being that any single 'rogue' thread
   within the process can cause the whole process to fail. Programming
   threads is also more complex than for simple processes as kernel code
   and libraries must have 100% re-entrant code. Special care must be
   taken to ensure that pre-emption cannot occur within critical sections
   of code within which inconsistencies could occur should another thread
   gain access at the wrong time. Other such problem is "what happens if
   a thread forks another process ?", it must be defined how threads
   within a process are affected in this case.
   
   
   Linux
       
   
       
   Windows NT
       
   There are two types of threads: user-space and kernel-space.
       User space threads consist of internal cooperative multitasking
       switches between sub tasks defined with a process.
       A thread may send a signal, perform it?s own switch or be invoked
       by a timer to give up the thread of execution. The user stack is
       then manipulated to save the thread context Switching is typically
       faster for user threads than kernel threads.
       
       User threads have disadvantages in that starvation can occur if
       one thread does not give up the CPU. Also should a thread become
       blocked waiting on a resource, all other threads will be blocked
       as well. User threads cannot take advantage of SMP systems should
       such a multi processor environment be available.
       
   
       
   Similarly to its implementation of processes, Windows NT threads are
       implemented as Objects.
       Certain attributes of a thread may restrict or qualify the
       attributes applicable to the overall process.
       The thread has a context attribute which allows the operating
       system to correctly perform context switching as required.
       
       The Windows NT Posix subsystem does not support multi-threading,
       though the OS/2 and Win 32 subsystems do.
       All threads are subject to manipulation by the kernel, which will
       schedule their priority for access to the CPU. The kernel is
       concerned with its own view of a thread called a kernel thread
       object. The kernel does not use thread handles but instead
       accesses threads directly from it's kernel process object.
       Windows NT threads support SMP, with individual threads (and
       processes for that matter) having a defined processor affinity
       which can define on which of a selection of available processors
       the thread may be run.
       
   Kernel-space threads may be implemented in the kernel by allocation of
       a thread table to a process. The kernel schedules threads within
       the time quantum allocated to the process.
       This method requires slightly more overhead for context switching
       but advantages include true pre-emption of tasks, thus overcoming
       the starvation problem. I/O blocking is also no longer a problem.
       Threads can automatically take advantage of SMPs with run time
       efficiency improving linearly as CPUs are added.
       
   
       
   
                                                       [LINK][LINK][LINK]
       
       
       
       
                                                                         
                                                                         
   Timers
   
   Linux
       
   
       
   Windows NT
       
   The kernel records a process's creation time and the CPU time it has
       consumed including the time spent in user mode and time spent in
       system mode.
       Processes may also have their own interval timers, which may be
       single shot or periodic. These can use signals to notify the
       process when timers expire.
       
   
       
   Timer objects exist as an Executive support service which will record
       the passage of time. After a set time or on expiry of a time
       interval the object becomes 'signalled' which will release all
       waiting threads.
       
   
   
   
                                                       [LINK][LINK][LINK]
                                                                         
                                                                         
                                                                         
   Virtual Memory
   
    Virtual memory provides a way of running more processes than can
   physically fit within a computer's physical address space.
   
    Each process that is a candidate for running on a processor is
   allocated it's own virtual memory area which defines the logical set
   of addresses that a process can access to carry out it's required
   task. As this total virtual memory area  is very large (typically
   constrained by the number of address bits the processor has and the
   maximum number of processes it supports), each process can be
   allocated a large logical address space (typically 3Gb) in which to
   operate.
   
    It is the job of a virtual memory manager to ensure that active
   processes and the areas they wish to access are remapped to physical
   memory as required. This is achieved by a method of swapping or paging
   the required sections (pages) into and out of physical memory as
   required.   Swapping involves replacing a complete process with
   another in memory whereas paging involves removal of a 'page'
   (typically 2-4kbytes) of the process's mapped memory and replacing it
   with a page from another process.  As this may be a computer intensive
   and time consuming task, care is taken to minimise the overhead that
   it has. This is done by usage of a number of algorithms designed to
   take advantage of the common locality of related sections of code and
   also  only carrying out some operations such as memory duplication or
   reading when absolutely required ( techniques known as copy on write,
   lazy paging and demand paging).
   
   The virtual memory owned by a process may contain code and data from
   many sources. Executable code may be shared between processes in the
   form of shared libraries, as these areas are read-only there is little
   chance of them becoming corrupted. Processes can allocate and link
   virtual memory to use during their processing,
   
    Some of the memory management techniques used by many operating
   systems, including Linux and Windows NT include :
   
    Page based protection mechanism Each virtual page has a set of flags
     which determine the types of access allowed in user mode or kernel
                                   mode.
      Demand paging / lazy reading the virtual memory of a process is
    brought into physical memory only when a process attempts to use it.
    Kernel and User modes of operation Unrestricted access to process's
   memory in kernel mode but access only to it's own memory for a process
                               in user mode.
   Mapped files Memory is extended by allowing disk files to be used as a
           staging area for pages swapped out of physical memory.
     Copy on write memory When two processes require access to a common
     area of code the virtual memory manager does not copy the section
   immediately as if only read access is required the section may be used
   safely by both processes. Only when a write is requested does the copy
                                take place.
    Shared memory An area of memory may be mapped into the address space
     of more than one process by the calling of privileged operations.
    Memory Locking To ensure a critical page can never be swapped out of
    memory it may be locked in, the vritual memory manager will not then
                                 remove it.
      For Windows NT : Object based Memory Protection The NT security
   reference checks access permissions for any process attempting to open
            a handle to that memory section or map a view of it.
                                      
                                      
   
   
                                      
                                      
                                                       [LINK][LINK][LINK]
                                                                         
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                           Build your own DBMS!!
                                      
                     By Idan Shoham, idan@m-tech.ab.ca
     _________________________________________________________________
   
   next up previous
   Next: Introduction
   
   Roll your own DBMS?!?
   
   Author: Idan Shoham
   
   Document release date: May 28, 1997
     _________________________________________________________________
   
   
     * Introduction
     * A little history
     * Problems with off-the-shelf technology
     * Summary of design requirements
     * Architectural answers to design questions
     * The components
          + Client software
          + Database and network protocols
          + Server software
     * Bonus features
     * A working system!
     * A solution looking for new problems
     * References
     * About this document ... 
     _________________________________________________________________
   
   next up previous
   Next: Introduction
   
   
    idan@m-tech.ab.ca
     _________________________________________________________________
   
                       Copyright © 1997, Idan Shoham
         Published in Issue 23 of the Linux Gazette, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next next up previous
   Next: A little history Up: Build your own DBMS!! Previous: Build your
   own DBMS!!
   
                                 Introduction
                                       
   This article describes a project, recently completed at M-Tech, for
   which we constructed a client/server database management system
   (DBMS), from the ground up. This DBMS was built using off-the-shelf
   components, some tools recycled from previous projects and a modest
   amount of new code.
   
   You might ask why we developed a new DBMS, considering the diversity
   and quality of commercial DBMS-s already on the market. The answer
   lies in the stringent demands of a project we had contracted for. This
   project required an inexpensive, fast, reliable DBMS that could
   support highly secure transactions over a slow public network. There
   are commercial DBMS products that are inexpensive, fast, or secure,
   but we are not aware of any that combine all of these merits, as well
   as responsive performance over something as slow as a modem.
   
   This article is of particular interest because the technology we
   developed for this project can be utilized to construct systems that
   carry any of the stringent demands of our original project, such as:
   
     * Responsive DBMS performance over a slow TCP/IP network.
     * Strong security, based on public-key cryptographic technology.
     * Inexpensive system implementation, component licensing and ongoing
       maintenance.
     _________________________________________________________________
   
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   Next: A little history Up: Build your own DBMS!! Previous: Build your
   own DBMS!!
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: A working system! Up: Build your own DBMS!! Previous: Server
   software
   
                                Bonus features
                                       
   Over the course of about six months, we implemented the entire
   client/server architecture. With all the building blocks in place, we
   could implement some extra features with relative ease:
   
     * We needed a report writer; preferably one that could run on the
       server. By creating reports on the server, the client PCs would
       require minimal software and infrequent upgrades. Furthermore,
       reports could be produced very quickly, since no data would travel
       across any network, no matter how fast.
       We already had a system (from a previous project) that could
       convert a high-level description of a report into C source code,
       to be linked against CodeBase. We integrated stand-alone
       executable reports written using this tool into the server, so
       that a client could request a report and the server would deliver
       only the output.
     * Every Unix system is configured with a mailer. In our case, the
       mailer was just sendmail. We wanted to give the end-users access
       to e-mail, but over the encrypted SSL connection rather than
       directly. To do this, we added a rudimentary e-mail user interface
       to the client and a thin server, that just talks to sendmail over
       a local SMTP socket.
     * The client/server database, along with the server's ability to
       regularly execute tasks, allowed us to implement a simple bulletin
       system, where any user could post announcements and the server
       would automatically delete them after a period of time. The
       bulletins are stored using a regular table in the database, so
       access to them is controlled by the same mechanism that controls
       access to data elsewhere in the system.
     _________________________________________________________________
   
   next up previous
   Next: A working system! Up: Build your own DBMS!! Previous: Server
   software
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: A solution looking for Up: Build your own DBMS!! Previous: Bonus
   features
   
                               A working system!
                                       
   We built the infrastructure and used it to build a mental health
   clinical information database - which is now used by qualified,
   authorized clinicians throughout Calgary to share clinical data about
   patients. The system is ``live,'' the feedback from users has been
   positive and there are already hundreds of trained, active users.
   
   The MHCID system as currently implemented allows users to enter data
   about new patients, find clinical records about existing patients,
   send each other e-mail as well as read and post bulletins. There is a
   friendly interface by which an authorized user can add and delete
   users, update lookup tables and change the access control model.
     _________________________________________________________________
   
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   Next: A solution looking for Up: Build your own DBMS!! Previous: Bonus
   features
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: References Up: Build your own DBMS!! Previous: A working system!
   
                      A solution looking for new problems
                                       
   All these tools .. all this infrastructure .. just one application? We
   are already using the same infrastructure to develop two additional
   applications - one in a mental health outcomes measurement study, and
   another for a palliative care system.
   
   There is nothing specific to health applications about the technology,
   though! Any system that requires one or more of the key features of
   the technology: fast response over a low-bandwidth, high-latency
   network; strong security; low licensing cost; low administration /
   support costs can benefit from this architecture.
     _________________________________________________________________
   
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   Next: References Up: Build your own DBMS!! Previous: A working system!
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: About this document Up: Build your own DBMS!! Previous: A
   solution looking for 
   
                                  References
                                       
     * To find out more about SSLeay: SSLeay
     * To find out more about Zinc: Zinc
     * To find out more about CodeBase: CodeBase
     * To find out more about M-Tech: M-Tech
     _________________________________________________________________
   
   next up previous
   Next: About this document Up: Build your own DBMS!! Previous: A
   solution looking for 
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Up: Build your own DBMS!! Previous: References
   
                            About this document ...
                                       
   (c) 1996,7 M-Tech Mercury Information Technology, Inc.
     _________________________________________________________________
   
   next up previous
   Up: Build your own DBMS!! Previous: References
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: Problems with off-the-shelf technology Up: Build your own DBMS!!
   Previous: Introduction
   
                               A little history
                                       
   As mentioned earlier, the DBMS architecture described in this article
   grew out of the demanding requirements for a system we were contracted
   to develop. That system is now the Mental Health Clinical Integrated
   Database (MHCID). It allows clinicians in the mental health sector in
   Calgary to share clinical data about patients throughout all
   CRHA-sanctioned mental health clinics and hospitals in the city.
   
   The MHCID system presented us with these difficult requirements:
     * Communication between the sites must be supported using modems, so
       bandwidth was low (less than 30kb/s) and packet latency was high.
     * Patient clinical data is very confidential, so must be encrypted
       when transmitted across the telephone system.
     * User access to data must be strictly controlled, to support
       ethical and organizational requirements.
     * The system must log all access to patient data.
     * There are hundreds of users - up to 15 simultaneously connected to
       the server.
     * Client workstations were already deployed before we started
       development (from a previous pilot project). There was only a
       minimal budget for hardware upgrades.
     * The combined budget for software licenses, server equipment and
       development was relatively small.
     _________________________________________________________________
   
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   Next: Problems with off-the-shelf technology Up: Build your own DBMS!!
   Previous: Introduction
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: Summary of design requirements Up: Build your own DBMS!!
   Previous: A little history
   
                    Problems with off-the-shelf technology
                                       
   In order to minimize the development and debugging efforts, a project
   like this would ideally use as much ``off-the-shelf'' technology as
   possible.
   
   We first considered using a commercial DBMS, due to the many available
   options: file/server systems such as FoxPro or MS-Access and
   client/server systems such as Oracle, Sybase or SQL-Server. However,
   it soon became apparent that a file-server solution would not perform
   adequately in a modem-based network. Also, of the client/server
   technologies, only Oracle offered a cryptographically secured solution
   (Secure Oracle). While this appeared to be a sound technology, the
   licensing costs alone would have exceeded the total project budget.
   
   Not only was price a significant problem, but we were also unsure of
   the performance implications of running Oracle's SQL*Net protocol over
   a 30kbps link. SQL*Net is designed for a LAN environment, where 1Mbps
   can usually be sustained for the life of a transaction.
   
   There had to be a better way!
     _________________________________________________________________
   
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   Previous: A little history
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: Architectural answers to design Up: Build your own DBMS!!
   Previous: Problems with off-the-shelf technology
   
                        Summary of design requirements
                                       
   To summarize, we had to build a system that met the following
   requirements. To succeed, every criteria had to be met in full:
   
     * The system had to operate in real-time. Data entered at one site
       must be immediately available at all other sites.
     * The system had to be secured against eavesdropping, wire-taps,
       etc.
     * The system had to be responsive to users even when communication
       latency was high (on the order of 1-3 seconds) and the bandwidth
       was low (at most 30kbps).
     * All administration had to be handled by a trained end-user.
     * Access to the data had to be strictly controlled and the rules for
       access control were subject to modification by the
       user-administrator.
     * Access to data had to be logged and the detail with which logs
       were made had to be subject to run-time control by the
       user-administrator.
     * The client user interface had to be very intuitive - users with no
       computer experience (literally: where's the on-switch?) had to be
       able to use the system after a 1/2 hour of training.
     * The system had to be inexpensive to develop, deploy, administer
       and maintain.
       
   The last criterion makes the preceding ones even harder to achieve!
     _________________________________________________________________
   
   next up previous
   Next: Architectural answers to design Up: Build your own DBMS!!
   Previous: Problems with off-the-shelf technology
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: The components Up: Build your own DBMS!! Previous: Summary of
   design requirements
   
                   Architectural answers to design questions
                                       
   To address the aforementioned requirements, we clearly had to use a
   client/server database technology. To defend against eavesdropping, we
   had to encrypt all communications.
   
   At the time, IPsec and virtual private networks were not available.
   Even today, these are young technologies and VPNs are not yet suitable
   for implementation on client workstations. The solution had to be
   encryption in the DBMS protocol. To do this, we could either buy
   Secure Oracle (which would put the project over budget), or roll our
   own solution.
   
   We had to write a DBMS engine which would encrypt all communication,
   be responsive when the bandwidth was low and the latency high, support
   strong authentication, access controls and auditing features. On the
   bright side, we really didn't need an SQL engine, or a generalized
   query engine at all. (More on queries and reports later, though!)
     _________________________________________________________________
   
   next up previous
   Next: The components Up: Build your own DBMS!! Previous: Summary of
   design requirements
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: Client software Up: Build your own DBMS!! Previous:
   Architectural answers to design 
   
                                The components
                                       
   A client/server architecture consists of several parts:
   
     * A client:
          + A (graphical) user interface.
          + A DBMS communication package.
          + A network communication package.
          + An operating system.
     * A network, which connects the client to the server.
     * A server:
          + A package for physically accessing a database, including
            record locking, read/write, etc.
          + An access control / logging module.
          + An authentication module.
          + A database protocol and code to support it.
          + A network communication package.
          + An operating system.
       
   To implement a client/server database, each of the components above
   must be implemented; either using existing software or by writing new
   code. We designed a new client/server system primarily in order to
   implement our own secure protocol. Accordingly, we wrote our own code
   to handle the database communication protocol. The other components
   are off-the-shelf, in order to reduce the programming work.
   
   The following are the components used in our system:
   
   Location Component Technology
   Client operating system Win32
   network communication package TCP/IP + SSL
   client DBMS communication package Our own code
   graphical user interface Zinc
   Network protocol TCP/IP
   Server operating system Linux
   network communication package TCP/IP + SSL
   database protocol + support code Our own code
   authentication module Our own code
   access control / logging module Our own code
   package for physical DBMS access CodeBase
   
   The architecture is illustrated in Figure 1.
   
      figure44
   Figure 1: System architecture
     _________________________________________________________________
   
   
     * Client software
     * Database and network protocols
     * Server software
     _________________________________________________________________
   
   next up previous
   Next: Client software Up: Build your own DBMS!! Previous:
   Architectural answers to design 
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: Database and network protocols Up: The components Previous: The
   components
   
Client software

   We chose Win32 for the client interface because it is common,
   well-accepted and friendly.
   
   We used the Zinc platform-independent graphical user interface library
   to develop the user interface of the client software. Zinc allowed us
   to save time writing Windows screen code and be sure that future
   versions of the software could easily be ported to other operating
   systems (e.g., Motif, Curses, NextStep, MacOS, OS/2 PM).
     _________________________________________________________________
   
   next up previous
   Next: Database and network protocols Up: The components Previous: The
   components
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: Server software Up: The components Previous: Client software
   
Database and network protocols

   We used TCP/IP as the communication protocol because it is also
   common, well supported and independent of physical media. Although
   modems are used in the MHCID system today, we anticipate other media
   in the future.
   
   In order to secure the database communications, we needed an
   efficient, robust and proven encryption protocol. Developing
   encryption algorithms and secure protocols is a complex task, fraught
   with danger. Rather than invent our own, it was preferable to use
   something ``tried and true.'' SSL, developed by Netscape, is just such
   a protocol. It can use public-key cryptography to authenticate the
   server and to exchange a secret session key in a secure fashion.
   
   Fortunately, an efficient implementation of SSL is available on the
   Internet, courtesy the hard work of Eric Young and Tim Hudson -
   SSLeay.
   
   We developed our own DBMS protocol using a simple syntax, on top of
   SSL sockets. A set of three-letter commands was defined, which
   supports everything from logging in, to multi-record read and write
   operations. The client sends commands to the server, and the server
   replies with any relevant data, plus a status code. The protocol was
   designed to be terse, simple and to support every operation required
   by our client software in a single operation.
   
   Some examples of how the protocol speeds up the client/server
   interaction are:
     * The client can open every table it needs for a given operation
       with one command.
     * The client GUI frequently needs to validate a data entry field.
       Only one command is needed to check whether ``value X appears in
       column Y in some row of table Z.''
     * The client can read many records from one or more related tables
       on the server with a single command.
     _________________________________________________________________
   
   next up previous
   Next: Server software Up: The components Previous: Client software
   
   
    idan@m-tech.ab.ca
    
   next up previous
   Next: Bonus features Up: The components Previous: Database and network
   protocols
   
Server software

   We chose to implement the server on Linux for a number of reasons:
     * It's a lot easier to write Unix software than Windows software.
       This is particularly true of network communications code and
       server processes.
     * In our experience, Linux is a very fast, very reliable operating
       system. It's also very well supported by the Internet community.
     * The price is right!
     * We were already very familiar with Linux.
       
   Once the operating system and database protocol design were fixed, all
   we needed was a physical database access system. Rather than write our
   own, we used CodeBase, which allows programs written in C to
   manipulate xBase-compatible database files. We used CodeBase because
   we were familiar with it from previous projects and have found it to
   be fast and reliable.
     _________________________________________________________________
   
   next up previous
   Next: Bonus features Up: The components Previous: Database and network
   protocols
   
   
    idan@m-tech.ab.ca
    
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
  Unioncamere Emilia-Romagna: an Italian Public Administration Using Linux
                                      
                          By Giampaolo Montaletti
     _________________________________________________________________
   
   Two year ago the Internet was exploding in Italy. A lot of newspaper
   reported wishfull informations about it:
   
   the Net is over 40 million of people looking for your information;
   
   the Net is cheap and fast
   
   the Net is growing so fast that you can't keep up.
   
   Unioncamere is the regional association of Chamber of Commerce of The
   italian region Emilia-Romagna (Bologna is the capital, but Rimini is
   the well-world-wide-know city). Chambers of Commerce in Italy are
   public bodies, and all the firm must be associated to the Chamber of
   Commerce and have to pay an annual tax.
   
   As you can easily understand firms are not so happy to pay tax, so we
   are always under a big pressure from them. They want to have a lot of
   data about economy, markets and financial tools in a fast and viable
   way and without a lot of cost of maintenance.
   
   Internet was the choiche and Linux was the system of choiche! At the
   beginning of september 1995 we was starting the project of
   establishing a server , at the end of october we was on line with the
   www server.
   
   To give a fast stratup has been very important the contribution of
   Massimo Poli, and indipendent consultant running a lot of sites and
   using Linux only; you che reach him at www.sextant.it, the little firm
   he is managing.
   
   When you pay a consultant using Linux you are sure to pay his work
   only, and not a bogus "assistance service" or "online help". This is
   very important in establishing a good and clear contract.
   
   When we started whith the site we was using a coax-ethernet based LAN
   with 30 users about. The 2 internal servers was (and they are working
   too) Novell 3.12 based. Novell is IMHO a good NOS for two tasks:
   printing and sharing disks. Novell tecnology is quite stable: our
   server BOSS is up and running without shutdown from 6 of january 1997.
   But we was needing a good e-mail server and a workgroup solution.
   
   We decided to move to Linux for internal E-mail as for Internet
   E-mail. In this way you have an affordable solution with low costs and
   no standard problems.
   
   The site is growing fast. Using Apache solution and virtual server
   capacibility we are hosting two Chamber of Commerce and we are going
   to host the other 7 in the region in the next future. Mailing lists,
   restricted users areas, on-line database with www interfaces and other
   usefull instruments are all in use in our server box. Security was
   another big problem, but not so big using Linux firewalls. In 1996 we
   have installed a second server cruncing the Lan in two segments.
   
   Whit Linux we have solved a lot of problem at low cost, but Linux is
   excellent in networking and network management. Now I'm administrating
   the full network (SMB servers included) with my Linux box. I'm now
   mounting volumes from Novell and fron NT 4 workstations, I'm already
   printing from Novell printer server. Because I'm not a full time
   administrator (I'm really working here as Chief of the Research and
   develpment office, and I'm not an hacker, but a Senior Economist) I
   use Linux for Office work too. Applixware is the solution I prefer,
   the only 200 $ I've spent for software whith Linux. The solution
   provided by Applixware is good because I share my work with Microsoft
   maniac in my office, and I need the filters for Word and Excel that
   Applixware is providing with version 4.3.
   
   Workgroup solutions are now provided by a linux box with BSCW
   software, a not well know piece of software in the linux world, but a
   vary usefull one if you plan to establish an intranet whit workgroup
   solutions.
   
   For all the 4 linux boxex running in our network we use standard pc's.
   2 of the four machines running are old Pentium 90 and 133 Mhz that
   people with Win95 wants no more, because those are "weak machines".
   
   As you have already understood reading this article, we are not
   linux-religious or linux-maniac or linux-fanatic. In our offices we
   run Novell and Os/2 and Win* machines as well. But we use linux
   because for some tasks is the best solution, only the best solution.
   Is stable, well supported and documented. If you want to run a new
   project where the Internet or the Intranet is involved and your boss
   is not able to understand or you have no more money, go to the room
   were the old-and-disrupted-pc's are and set-up a linux box.
   
   Giampaolo.Montaletti@rer.camcom.it AKA Monty
     _________________________________________________________________
   
                   Copyright © 1997, Giampaolo Montaletti
         Published in Issue 23 of the Linux Gazette, December 1997
     _________________________________________________________________
   
   [ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next 
     _________________________________________________________________
   
                 An Introduction to the Midnight Commander
                                      
               by John M. Fisk <fiskjm@ctrvax.vanderbilt.edu>
                               October, 1997
                               Nashville, TN 
                                      
                                  Abstract
                                      
     The Midnight Commander is a directory browsing and file
     manipulation program that provides a flexible, powerful, and
     convenient set of file and directory operations. It is capable of
     running in either a console or an xterm under X11; mouse support is
     native under X11 and is provided by the gpm mouse server when used
     in a Linux console. A sophisticated Virtual File System (VFS)
     supports directory-like browsing and file operations for a variety
     of common archive formats as well as FTP and network connections.
     Its basic operation is easily mastered by the novice while
     providing a rich feature set and extensive customization.
     
Introduction

   The last couple years has seen the release of a bevy of well designed,
   X based file managers including FileMan, FileRunner, Linux Explorer,
   TkDesk, X-Files, and Xplorer to name a few. Some of these are "works
   in progress" but all show promise and are well worth having a look at.
   
   Despite this, one of my favorites, and now old enough in the "Linux
   Epoch" to be called venerable, is Miguel de Icaza's Midnight Commander
   (mc). The README describes mc as:
   
     a free Norton Commander Clone with many useful features... The
     Midnight Commander is a directory browsing tool which bears a
     certain remote resemblance to John Socha's Norton Commander for
     DOS.
     
   Its stability, ease of use, flexibility, and rich feature set make it
   quite a powerful tool. Its simplicity makes it easy for novices to
   quickly master the basics. Among the capacities it boasts are:
     * support for all basic file operations including move, copy,
       rename, delete, chown, link, view, and edit
     * a built in Virtual File System that allows browsing of archives
       such as tar, compressed tar, rpm, deb, zip, cpio, lha, rar, and
       zoo files as well as remote files via FTP or the Midnight
       Commander's own mcfs protocol
     * mouse support in xterms under X or at the Linux console via the
       gpm mouse server
     * built in text and hex viewer/editor as well as support for
       external viewer and editors
     * subshell support for the bash, tcsh, and zsh shells
     * built in Find File capacity
     * background copy or move operations
     * online help system
     * and much more...
       
   The manual page for mc is well over 50 pages in length, giving some
   indication of its complexity. In this short article I won't be able to
   cover mc in this depth, but will try to touch on the basics: getting
   the sources, compiling and installation, and basic use and features.
   This is probably best read while sitting at your computer and
   experimenting with the various features as you go. Let's start by
   compiling and installing mc.
   
Going To The Source

   Sources and precompiled binaries are available at a number of
   locations including the canonical GNU FTP archive
   prep.ai.mit.edu/pub/gnu/ and the sunsite FTP archive at
   sunsite.unc.edu/pub/Linux/utils/file/managers/mc/. The official web
   page is http://mc.blackdown.org/mc/ where the most recent public and
   development releases may also be found. There are, additionally,
   mailing lists for both users and developers to which you can subscribe
   from this site.
   
   In addition, most Linux distributions including Debian, RedHat,
   Slackware, and their derivatives provide precompiled packages in
   *.deb, *.rpm, or *.tgz formats. If you feel a bit shaky at the
   prospect of compiling your own programs, or are in a hurry to get
   going, then these provide an easy means of obtaining and installing
   mc. Check the documentation that came with your distribution as to the
   specifics of using the package management system they provide. At a
   minimum you could try:

        $ installpkg mc-xxx.tgz
        -OR-
        $ rpm -i mc-xxx.rpm

   for Slackware or RedHat based systems in which "mc-xxx.{tgz,rpm}" is
   the name of the package.
   
   In the pioneering spirit of Linux's "Do It Yourself And Learn", I'd
   like to suggest that you compile and install mc from its sources. It's
   not that difficult and if you've not done much of this then mc is an
   ideal program on which to start since it is quite well behaved.
   
   For the purposes of this article I'll be using mc version 4.1.5 which
   is the most current at the time of this writing. If you ftp the
   sources from sunsite or one of its mirrors then you might also want to
   retrieve a couple other useful packages that support mc: the rxvt X
   window terminal, Allesandro Rubini's gpm mouse server, and Theodore
   T'so and Remy Card's e2fsprogs package which allows file undelete
   capacity to be compiled into mc. All of these are available at sunsite
   or its mirrors in the /pub/Linux/utils/file/managers/mc/ directory.
   
Compiling and Installing Midnight Commander

   In this section, I'll assume that you've gotten the *.tar.gz source
   file, that you'll unarchive the sources into /usr/src, and that you'll
   install mc and its support files under /usr/local. You can obvious
   compile and install mc in any directory you wish: just change the
   pathnames to suit your preferences. To unarchive the sources do:

        $ cd /usr/src
        $ tar -xvzf /path/to/mc-4.1.5.tar.gz

   in which "/path/to/mc-4.1.5.tar.g" is the path to the source file --
   i.e., if you downloaded the file to your home directory you'd use:

        $ tar -xvzf ~/mc-4.1.5.tar.gz

   This assumes that you're using the GNU version of tar which handles
   gzipped files using the "-z" option. If you are using a different
   version of tar you can also do:

        $ gzip -dc /path/to/mc-4.1.5.tar.gz | tar -xvf -

   After unarchiving the file change to the mc-4.1.5 directory where
   you'll find both the sources and program documentation. The mc
   distribution comes with two files outlining the installation process:
   INSTALL and INSTALL.FAST. If you're not used to compiling programs
   from source then read INSTALL.FAST which gives a concise explanation
   of the process as well as options that you can use to customize where
   mc gets installed and what features it includes. If you're a bit more
   adventurous, then have a look at the INSTALL document which goes into
   a good deal more detail. For our purposes, I'll go through the process
   of compiling mc with Virtual File System, SLang, and gpm mouse support
   (which is very little work since these are the defaults). We'll
   install the mc executable under /usr/local/bin and its support files
   under /usr/local/lib/mc. You should log in as root in order to compile
   and install mc.
   
   As with many other GNU programs, mc uses an autoconf script to detect
   the various features of your system and then create the needed
   makefiles. This greatly simplifies the build process. An additional
   feature that this supports is the ability to declare compilation
   options such as what features to include and where the program will be
   installed. Both INSTALL and INSTALL.FAST give a listing of these
   features. We'll use:

        $ ./configure --prefix=/usr/local --with-slang > configure.log 2>&1 &
        $ tail -f configure.log

   The mc configure script defaults to compiling in SLang, mouse, and X
   Window support (so the --with-slang option wasn't really necessary).
   So as to have a record of what happened use > configure.log 2>&1 which
   saves all the output to configure.log. Use tail -f configure.log to
   view the log file as the configure script progresses. When configure
   is finished it prints a summary of the features and compile options
   that will be used. Use Control-C to exit out of tail.
   
   If there were no error messages (and there should be none) then
   compiling and installing is as simple as:

        $ make
        $ make install

   If you want to create a log file of the build and installation process
   you can use:

        $ make > make.log 2>&1 &
        $ tail -f make.log
        $ make install > install.log 2>&1 &
        $ tail -f install.log

   And that should do it! To ensure that mc was installed properly type:
        $ mc -V

        Midnight Commander 4.1.5
        with mouse support on xterm and the Linux console.
        Edition: text mode
        Virtual File System: tarfs, extfs, ftpfs, mcfs, undelfs.
        With built in Editor
        Using system-installed S-lang library with an unknown terminal database
        With subshell support: as default
        With DUSUM command
        With support for background operations

   This returns version and compilation information. If you've compiled
   and installed the 4.1.5 version but mc -V returns a previous version
   then you'll need to find and uninstall or rename the previous version.
   If you use the bash shell, type:

        $ type -a mc

   This should return the paths to all mc executables. At this point, you
   can either use your distribution's package manager to uninstall the
   previous version or temporarily rename it to something like mc.old.
   You should now be ready to start exploring mc!
   
The Midnight Commander Tour

   Without trying to be exhaustive I'd like to touch on the following
   topics:
     * the mc interface
     * directory navigation
     * file selection
     * basic file operations
     * viewing and editing files
     * using mc's panels
     * VFS coolness
     * popups, shortcuts, and a few more tricks
       
   and we'll finish with some closing remarks and suggestions. My aim is
   to cover the salient features and give you a feel for what mc is able
   to do.
   
  The mc Interface
  
   While mc has a number of command line options, in normal use simply
   type mc at the command prompt to start it. You can run mc either at
   the console or in an xterm. If you use mc under X then I'd strongly
   suggest that you rxvt instead of an xterm as both the colors and line
   drawing characters are well supported under rxvt. As a side note, if
   you find that the line drawing characters are not drawn correctly,
   then make sure that the TERM environment variable has been set to
   "xterm":

        $ echo $TERM
        linux

        (if this returns "linux" as above, then do the following:)
        
        $ export TERM=xterm
        $ echo $TERM
        xterm
        $ mc

   At this point, you should see something like:
   
   [INLINE]
   
   This main screen is similar to what you'd see at the console (the
   window has been sized to 80x24). It's main components are:
     * menubar at the top which contains drop-down menus
     * directory panels which contain file listings
     * a "hint line"
     * a command line
     * function key labels at the bottom
       
   If you move the mouse around you should also see a pointer on the
   screen. If you don't see a cursor when using mc at the console then
   make sure that the gpm mouse server is running:

        $ ps -ax | grep gpm
   73  S0 S    0:00 /usr/bin/gpm -t ms
  104  ?  SW   0:00 (gpm-root)
 5465  ?  D    0:00 grep gpm

   If it isn't then (assuming you're using a Microsoft-compatible serial
   mouse) start it using gpm -t ms. The "-t" option specifies the type of
   mouse; if you're using a different kind of mouse then consult the gpm
   manual page for the command line option to use.
   
   To activate one of the menus you can either click on it with the mouse
   or hit the F9 key and use the arrow keys to move the desired menu
   item. This brings up one of the important features of mc: almost all
   operations can be performed using either the mouse or via keystrokes.
   Which method you use is a matter of personal style and preference
   although, as we'll see in a bit, using keystrokes can be a
   considerable time saver especially if you are a touch typist.
   
   The directory panels are where most of the action takes place. mc is
   normally run in this two-panel mode although single panel mode is also
   supported. The panels provide a view of two directories at once with
   one of them being the "current directory." Most all file operations
   are performed on files in this current directory (although copy,
   rename, and move operations default to using the non-current directory
   as the "target" directory). To select one directory panel simply click
   the mouse anywhere in the panel. You can also use the TAB key to
   switch the current directory from one panel to the other.
   
   The command line at the bottom functions just as you'd expect: simply
   type the command to execute and mc runs it just as if you'd entered it
   at the shell prompt. Just above the command line is the hint line (at
   the console; in an xterm it uses the title bar) which displays a
   series of hints and suggestions.
   
   Finally, the bottom line of the window display the function key
   mappings. Pressing F1 brings up the Help menu, F2 brings up the User
   Menu, F3 let's you view a file, and so forth. Note that clicking on
   any of these with the mouse results in the same action.
   
   In addition to this main window there are a number of popup dialog
   boxes which are used for specific operations. I'll cover several of
   these shortly. For now, let's turn to issues of navigation.
   
  Directory Navigation
  
   Moving from one directory to another is quite simple: in the current
   directory panel you can either:
     * select a directory, by clicking on it with the mouse or moving to
       it using the arrow keys, and then hit RETURN
     * double clicking on a directory using the mouse
     * use the cd command in the command line
       
   Any of these methods will cause the directory you've selected to be
   listed in the current directory panel. Note that the cd command
   understands "tilde expansion" which is a shortcut for referring to
   your home directory -- i.e., entering cd ~/bin would change to the bin
   directory in your home directory. Also, clicking on the ".." entry
   will move to the current directory's parent as will entering cd .. on
   the command line. There is also a Directory Hotlist which we'll look
   at shortly that helps speed directory navigation.
   
   One other navigation aid to keep in mind is that movement within the
   directory panels can be accomplished using a variety of keystrokes,
   many of which are modeled after the emacs text editor. These include:
     * down arrow, Ctrl-n - move forward one line
     * up arrow, Ctrl-p - move backward one line
     * Page Down, Ctrl-v - move back one screen
     * Page Up, Alt-v - move backward one screen
     * Home, Alt-< - move to the top of the directory listing
     * End, Alt-> - move to the end of the directory listing
       
   Note that Ctrl-n means "hold down the control key and hit the letter
   n." There are a few other movement keystrokes available, but these are
   the most commonly used.
   
   Once you know how to move from one directory to another the next thing
   to do is learn how to perform basic file operations. But before doing
   that we'll need to take a quick detour.
   
  File Selection Mechanisms
  
   Most of the time you'll be copying, renaming, deleting, or moving
   single files and doing so is quite straightforward. However, there
   will assuredly be times which you'll want to do something to several
   files or a group of related files. Maybe you'll want to find an delete
   all the *.rej files after you've run the patch program; or you want to
   find and move all *.tar.gz files to a separate directory; or you want
   to copy selected documentation from a source distribution to a
   /usr/doc directory for future reference. All of these require
   selection of a group of files.
   
   First, we need to make a distinction between the currently selected
   file or directory and marked or tagged files. The currently selected
   file is simply the one that is highlighted in the current directory
   panel. If you want to delete foo.txt simply move the highlight bar to
   that file and hit F8 to delete it. However, if you want to delete a
   group of files then you'll need to tag them.
   
   Tagging can be done in a couple ways. The simplest is to either click
   on the file or directory using the right mouse button or move the
   highlight bar to the file and hit Ctrl-t (that is, hold down the
   control key and hit t). In this way you can tag any number of files
   for copy, deletion, moving, and so forth.
   
   If the files you want can be specified by a shell pattern (such as
   *.tar.gz for all the gzipped tar files or foo_??.txt for foo_01.txt,
   foo_02.txt, foo_03.txt, etc., then you can use the following
   shortcuts:
   
   To select a group of files by pattern hit the "+" key
          This will cause a dialog box to appear in which you can enter
          the search pattern. Note that entering the "*" wildcard will
          select all the files in the directory.
          
   To select all the files in the directory hit the "*" key
          This has the same effect as using the + key and then entering
          "*"
          
   To unselect a group of files hit the "\" key or the "-" key
          A dialog box similar to that with the + key will appear; if you
          want to unselect all files then enter "*"
          
   Using pathname expansion (also known as filename globbing) is a fast
   and powerful way to select a group of similar files. Having now
   selected your files, let's see what you can do with them.
   
  Basic File Operations
  
   The Midnight Commander provides all of the basic UNIX file system
   operations including copy, delete, move, rename, link, symbolic link,
   chown, view, and edit. One of the nice features of mc is that it
   defaults to asking for confirmation before taking destructive actions
   such as file deletion or overwriting.This feature alone can save you a
   good deal of agony.
   
   Below is a short summary of the file operations. In the next section
   we'll look specifically at file viewing and editing. Keep in mind that
   while the summary below indicates the keystrokes for the various
   operations, all of these can be accessed using the "File" menu.
   
   copy: F5
          Normally, to copy a file from one directory to another select
          or tag the file(s) to copy in the current directory panel and
          change to the target directory in the other directory panel.
          Hit F5 or click on the Copy function at the bottom. Doing so
          brings up a dialog box:
          
          [INLINE]
          
          If you want to use a different directory than the one in the
          other panel or if you want to change the file name then you can
          use the to: entry box to do so.
          
          Also, when you perform a copy (and move or delete) operation mc
          displays a dialog box with a progress meter indicating the
          progress on the current file as well as the overall progress if
          a set of files has been selected.
          
   delete: F8
          After selecting or tagging a file or set of files hit F8 to
          delete them. Note that you'll be asked for confirmation. Also,
          mc is able to recursively delete a directory, but this, too,
          requires confirmation. If you're having to clean out a
          directory then I'd strongly suggest your using mc. It makes
          selecting files very easy and helps prevent costly accidental
          deletions.
          
          Note that at any time you can cancel an operation by hitting
          the Escape key twice.
          
   move/rename: F6
          These are very similar to the copy operation described above in
          that the destination directory defaults to the non-current
          directory in the case of the move operation. Note that renaming
          a file entails "moving" it to another filename. In this case,
          use the to: entry field in the dialog box to enter the new
          filename.
          
   (hard) link: Ctrl-x l
          To create a hard link to a file, select that file and enter
          Ctrl-x followed by the letter "l". A dialog box will prompt you
          for the filename for the newly created link.
          
   symbolic link: Ctrl-x s
          This is the same as that for a hard link except Ctrl-x is
          followed by the letter "s".
          
   chown: Ctrl-x o
          To change the owner or group of a file hit Ctrl-x followed by
          an "o". A dialog box is presented that will allow you to select
          owner and group from a list of valid values.
          
          Note that an "Advanced Chown" facility is available under the
          "File" menu. Until you're rather sure of what you're doing,
          this is probably best left alone.
          
   mkdir: F7
          While not a file operation per se, the MkDir command allows you
          to create a new directory in the currently active directory. A
          dialog box is presented that will prompt you for the new
          directory name.
          
   With these basic facilities you'll be able to do a good deal of day to
   day file system maintenance. To round things out, though, we'll need
   to add a couple other features.
   
  File Viewing and Editing
  
   The Midnight Commander comes with a very functional built in file
   viewer and text/hex editor. To view or edit a file hit the F3 or F4
   key respectively. Of particular note is the fact that mc provides
   formatting support for several common file formats including manual
   pages, HTML, and mail file. That is, that rather than viewing the raw
   file, mc will format the file according to the file format.
   
   For example, to view a manual page (even a gzipped page!) simply
   select the file and hit F3. If you have the mc source distribution
   handy, change to the doc directory and select the mc.1 file. Hit F3 to
   see:
   
   [INLINE]
   
   You can do similar things with HTML or mail files. In the case of HTML
   files it is worth noting that "viewing" the file is probably not what
   you expect as mc will strip out the hypertext tags leaving just the
   text. If you want to view an HTML file it is best to select the file
   and hit the RETURN key. Doing so "opens" the file and automatically
   executes (by default) lynx if you are at a console or netscape if you
   are running under X.
   
   The internal file view allows you to view files in one of two modes:
   ASCII or hex. When using the file viewer you'll notice that the
   function keys at the bottom change to a new set which are specific to
   the viewer. These include:
     * F2 toggles line wrapping
     * F3 exit the viewer
     * F4 toggle hex view mode
     * F5 goto line; a dialog box appears which will prompt you for a
       line number
     * F6 regular expression search
     * F7 normal search
     * F8 toggle raw or parsed mode
     * F9 toggle formated or unformatted mode: this affects attributes
       such as bold or underline which are displayed using various colors
     * F10 exit the viewer
       
   In addition Ctrl-s and Ctrl-r can be used for normal or reverse
   searches. Once you've started a search, hit the letter n to find the
   next match. Ctrl-l will repaint the screen; Alt-r will toggle the
   display of a ruler.
   
   In terms of moving around the viewer, mc has a rather egalitarian
   attitude and will accommodate almost any set of movement keystrokes
   that you've gotten used including those for emacs, less, and even some
   vi. Some of these are:
     * Home, Alt-< - move to head of file
     * End, G, Alt-> - move to end of file
     * up/down arrows - move forward or backward a single line
     * Ctrl-n, Ctrl-p - move forward or backward a single line
     * left/right arrows - scroll horizontally
     * Space, Page Down - move forward one page
     * b, Page Up - move back one page
       
   One very handy feature is that, if you are in View mode and hit Ctrl-f
   then the viewer will move to the next file in the directory and
   display it. In this way you can easily move through a set of files,
   viewing one right after the other.
   
   The internal file editor provides a full set of editing features and
   can be used to edit both text and binary files up to a size of 16
   megabytes. As with the Viewer, function keys have been remapped to
   provide common file editing functions. In addition, a popup menubar
   provides extensive editing operations including file insertion, save,
   copy, and load; block operations (copy, move, etc); search/replace
   functions; command macro recording and execution; and the capacity to
   pipe selected text through various shell commands such as indent or
   fmt. When not active, the menubar is hidden and file information is
   displayed in the topmost line. Here's a screen dump of the editor in
   action:
   
   [INLINE]
   
   Both the internal Viewer and Editor are designed to be fast and easy
   to use. You may, however, wish to use an external viewer (such as
   more, less, or most) or editor. To do so, you'll need to set your
   PAGER and EDITOR environment variables to the appropriate program and
   then use the Options->Configuration menu to unselect "use internal
   edit" or "use internal view". If you were using the bash shell and
   wanted to set the pager to "less" and the editor to "emacs", then use
   something like:

        $ export PAGER=less
        $ export EDITOR=emacs

   To make this change permanent you'd probably want to add these lines
   to your ~/.bashrc or ~/.bash_profile file. Having looked at the basic
   file operations let's return to mc itself and take a look at some of
   its other features.
   
  Using mc's Panels
  
   We've already noted that the directory panels are where most of the
   action takes place in terms of file operations. Accordingly there are
   a number of keystroke (and mouse) shortcuts that quickly let you
   change the panel view. In addition to directory listings, the panels
   can be quickly changed to display directory trees, quick file views,
   or extensive file information. If you spend much time at all working
   with files these features are invaluable.
   
    Basic Panel Operations
    
   As previously noted, you can quickly switch from one panel to the
   other using the TAB key (or Ctrl-i). You can also swap panels using
   Ctrl-u; note that the currently active directory panel does not
   change. Use Ctrl-r to refresh the directory display.
   
   To change the sort order of the files being displayed, use the
   (Left|Right)->Sort Order... menu item. This allows you to sort files
   by name, size, various time stamps, inode number, and so forth. You
   can also specify whether sorting should be case (in)sensitive or
   reversed. Sorting by size is very useful when trying to cull out files
   to recover disk space; sorting by date is useful when you are
   searching for a recently installed, created, or modified file in a
   directory with many files or are looking for ancient files that can
   safely be warehoused.
   
   As with sorting, use the (Left|Right)->Filter... menu item to filter
   the directory listing using shell patterns. For instance, suppose that
   you wanted a listing containing only files with a .c extension. In the
   Filter dialog simply enter "*.c" and all other files are removed from
   the listing. This is very useful when you wish to work with only a
   subset of files in a directory in an uncluttered setting.
   
   You can also cycle from two-panel to single-panel modes using Alt-t.
   This is particularly useful when you need to see the full directory
   information for a particular file. Note that you can also use the
   (Left|Right)->Listing Mode... menu item to customize what file
   information the panel lists. In addition, resize the panels using the
   Options->Layout... menu item. This allows you to split the panels
   either vertically or horizontally as well as set the number of columns
   for each panel using the ">" and "<" keys.
   
    Panel Modes
    
   Here's where the power of mc becomes apparent. The panels can be used
   in one of four modes which can be switched using the (Left|Right)
   menus:
   
   Listing Mode...
          This is the default directory listing mode. As noted above, you
          can customize what file information (name, permissions, time
          stamps, etc) is displayed
          
   Quick View...
          Provides a quick file viewer; it displays the file which has
          been selected in the other panel. This is very handy if you
          need a quick preview of a set of files. Note that the function
          key mappings at the bottom of the window display the usual
          viewer operations: all of the viewer features and keystrokes
          are available here. When previewing a set of files try
          increasing the size of the viewing panel using the
          Options->Layout... menu item.
          
   Info
          This works in a manner similar to Quick View: it displays a
          wealth of file or directory information.
          
   Tree
          As with Quick View and Info, the Tree view works with the other
          panel: it allows you to quickly navigate through the entire
          directory tree. By double clicking on a directory (or selecting
          it and hitting RETURN) its contents are displayed in the other
          panel
          
   One final shortcut to be aware of is Alt-o which makes use of both
   panels: by selecting a directory in the active panel and hitting
   Alt-o, its directory listing is displayed in the other panel. Hitting
   Alt-o repeatedly lets you quickly preview through a series of
   directories.
   
   Another powerful feature of mc is its ability to handle a multitude of
   archive types: this feature alone makes it a "must have" utility!
   
  VFS Coolness!
  
   VFS refers to the "Virtual File System" which mc implements. It is a
   powerful abstraction that allows you to view archives as though they
   were a directory: all the basic file manipulation operations can then
   be applied. The VFS file system handles an extraordinary number of
   archive types including tar, gzipped or compressed tar, RedHat's rpm
   package archives, Debian's deb package archives, gzip, zip, zoo, cpio,
   rar, and lha.
   
   To use it either select the file and hit RETURN or double click on the
   file. It's contents are then displayed as a directory listing.
   Navigation through the archive is the same as you'd use for a
   directory. This is a very useful feature when you need a single file
   or set of files from an archive. Note that if the archive is a
   compressed single file -- i.e., a gzip, zip, zoo, or lha compressed
   file -- then it is uncompressed and displayed.
   
   The VFS also supports its own FTP capacity which allows you to
   transparently manipulate files via FTP as though they were local to
   your machine. To log into an FTP server use the (Left|Right)->FTP
   Link... menu item and enter the URL or simply enter cd ftp://"URL" at
   the command line. For example, to ftp to the Linux Incoming directory
   at sunsite you would enter:

        $ cd ftp://sunsite.unc.edu/pub/Linux/Incoming/

   The hintbar at the console or the title bar under X will display
   progress information (e.g., logging in, retrieving directory listings,
   and so forth). You can now view and copy files just as you would using
   ftp. On file transfer (use F5 to "Copy" the file to your local
   machine) a progress meter displays percent transfer completed, ETA
   (estimated time of arrival), transfer rate, and the now commonplace
   "stalled" flag. Use the Options->Virtual FS... menu item to customize
   the VFS features such as anonymous login name and so forth.
   
   [INLINE]
   
   Note that mc also provides FTP service via a proxy server as well as
   network VFS. Having no experience with either of these I'll defer
   comment and simply refer you to mc's manual page if you are
   interested.
   
  Popups, Shortcuts, and a Few More Tricks...
  
   In this last section let's look at a few more shortcuts and
   suggestions for using mc effectively.
   
   A number of popups are built into mc that considerably speed up
   various operations. These include:
   
   Directory Hotlist: Ctrl-\
          Use this to create a popup hotlist of frequently accessed
          directories. The hotlist keeps a list of "alias-directory path"
          pairs. For example, if you use
          /usr/local/projects/C++/personal/ to store your personal
          programming projects then you could create an entry using the
          "New Entry" option and alias it to something like "Personal C++
          Projects".
          
          If you use mc as an ftp client then you can use the directory
          hotlist to keep the URL's for your frequented sites! To edit
          (add, modify, or delete entries) the list type in Ctrl-\ and
          then use "New Entry" to create a new entry: enter the URL for
          the site, including the path to the directory that you're
          interested in and then fill in the alias. Now, anytime that you
          need to ftp just popup the hotlist and select the site!
          
   Filename Search: Ctrl-s, Alt-s
          At the bottom of each directory panel is a mini-status box
          which lists the currently selected file or directory name. By
          hitting Ctrl-s or Alt-s the status box becomes an entry box in
          which you type in a file or directory name to search for. As
          you type, mc does an incremental search and automatically
          selects the file which matches the search. This is very handy
          when searching for a particular file in a large directory.
          
   Find File: Alt-?
          Find File provides an exceptionally fast and useful means of
          searching for a particular file based on a filename pattern,
          its contents, or both! For example, suppose that you kept a
          directory with USENET postings that you wanted to save and
          you're now looking for information on mysql. Use Find File with
          the "*" pattern for the filename and "mysql" for its content.
          It will then grep through the files and create a list of files
          containing "mysql". Clicking on one of the files in the list
          selects that file.
          
          Alternatively, if you were looking for all files with
          "announce" in the filename simply enter "*announce*" in
          Filename: (and leave the Content: entry box empty).
          
   Active VFS Directories: Ctrl-x a
          This pops up a dialog box listing all of the active VFS
          directories including those associated with FTP, archives, and
          so forth. When mc creates a VFS directory for an archive,
          network, or ftp connection, when you leave the directory the
          connection or resources are not immediately freed. So, for
          example, if you created an ftp connection to some host, you
          "close" it simply by changing back to a local directory. Until
          the connection times out (which you can set using the
          Options->Virtual FS...->Timeout for freeing VFS's menu item)
          you can reestablish the connection once again. This also works
          for archives (in this case, after the timeout, the memory
          resources are deallocated).
          
   Background Jobs: Ctrl-x j
          mc allows you to put copy and move operations into the
          background (select this option from the Copy or Move dialog
          box) which allows you to immediately return to mc. This is
          useful when you are copying/moving a large number of files or
          for ftp. Use the Background Jobs popup to quickly see what jobs
          are running and stop, restart, or kill them
          
   Another very handy feature which mc provides is subshell support. The
   way this works is by hitting Ctrl-o which creates a non-login
   interactive shell. This works for bash, tcsh, and zsh shells. Use this
   shell just as you would any ordinary shell. To immediately switch back
   to mc hit Ctrl-o once again, which allows you to toggle back and forth
   easily.
   
   If you are using the bash shell, keep in mind that non-login
   interactive shells only source your ~/.bashrc file (and not the
   ~/.bash_profile file) which means that if you have aliases or other
   customizations that you want to use then you should put these in
   ~/.bashrc. For example, if you use color-ls and find that file
   listings are not colorized, then you'll need to add alias ls='ls
   --color=tty' to your ~/.bashrc.
   
   One way to quickly create the "all-in-one-command-center" is execute
   mc and then start a subshell. From here, you can execute your favorite
   editor (emacs, xemacs, vim, etc.) and hit Ctrl-z to stop its execution
   and put it in the background. This returns you to the shell. Now, if
   you need to run mc then hit Ctrl-o; if you need to use your editor,
   type in fg which will resume the stopped program; and if you need to
   run any other program then use the shell as normal. This is a powerful
   means of keeping productivity tools readily available.
   
   One last feature I'd like to mention is mc's ability to help you sync
   the contents of two directories. This is particularly useful if you
   are keeping a backup set of files on another partition, a floppy, zip
   drive, etc. To use this list the "source" directory in one panel and
   the "target" directory in the other then hit Ctrl-x d. This will pop
   up a dialog box that allows you to select the type of directory
   comparison: Size simply compares files by size; Quick compares files
   by size and date; and Thorough does an exhaustive byte-by-byte
   comparison. After the comparison operation is complete (and after
   ensuring that the source directory is in the active directory panel)
   hit F5 (Copy) to copy files from your source directory to the target
   (backup) directory.
   
  Closing Comments and Suggestions
  
   I'd be remiss if I did not mention that mc comes with a very complete
   online help system which is accessed using F1. All of the information
   presented above, and a good deal more, can be accessed at any time
   from within mc using the help facility. Additional information can be
   found in the source distribution for mc: read the README, FAQ, and
   documents in the /doc directory.
   
   While I've attempted to cover most of the important features which mc
   offers there are many more that I've not had time to cover that I'll
   leave for you to discover! One suggestion would be to print out a copy
   of the mc manual page:

        man mc | col -b | lpr -

        -OR-

        man mc | col -b > mc.txt

   will print a copy of the manual page or save it to a text file which
   can be further processed. Since the manual is quite long you might
   want to use a program such as a2ps which converts ASCII files into
   Postscript. As with most UNIX-type programs, a2ps has a slew of
   command line options including the -f option which lets you specify
   the font size: select something in the range of 7.0 to 9.0 to get a
   small font which cuts down on the number of pages and leaves large
   margins in the sides for you to scrawl notes in.
   
   Also, while you are exploring, look through the Options menu for
   various items which will let you customize mc. Menus are a great place
   to poke around and see what facilities mc offers: most of the shortcut
   keystrokes I've mentioned are menu items (so you don't have to
   memorize the entire list of keystrokes!). For the adventurous:
     * Have a look at the undelete file system if you are using ext2
       under Linux. You'll need the ext2progs distribution and
       libext2fs.a to compile this support into mc.
     * Read about customizing the User Menu (this requires some knowledge
       of shell programming and so was skipped in this introduction).
     * Read about customizing the Extension file which associates a file
       extension with various actions (such as "viewing" or "opening").
       
   Finally, enjoy mc! As with many powerful programs, you'll most likely
   learn it incrementally, often just through the process of exploration
   and "playing with it." I've found mc to be indispensable and, with a
   bit of experience, I suspect that you will as well. Have fun!
   
   Date Last Modified: $Date: 1997/10/19 01:33:27 $
   
    "Linux Gazette...making Linux just a little more fun!"
     _________________________________________________________________
   
                           Linux Weekend Mechanic
                                      
                   Welcome to The Linux Weekend Mechanic!
                                      
        Published in the December, 1997 Edition of the Linux Gazette
                                      
        Copyright © 1997 John M. Fisk <fiskjm@ctrvax.vanderbilt.edu>
       The Linux Gazette (tm) is Copyright © 1997 Specialized Systems
                             Consultants Inc. 
     _________________________________________________________________
   
                             Welcome to the WM
                                      
   Hello y'all! Thanks for dropping in. I'm afraid that this month's
   weekend mechanic is going to be a bit sparser that usual. This
   semester has been a good deal more challenging than previous. I've
   been taking Compiler Design, Database Design, Computer Graphics (X
   Window based course), and Differential Equations and I'm really
   starting to "suck wind" about now (and I see lots of knowing smiles
   and folks waving white hankies out in the audience :-). To all of you
   in school, my sincerest best wishes!
   
   And once again, my 'ol Linux box has pulled though in the clutch. I've
   been leaning on it pretty heavily this semester and it's shown what a
   fantastic work horse it really is.
   
   In the compiler class we're building a "baby Pascal-like" compiler
   using C++ and while others sit for endless hours in the computer lab
   hacking away on the HP system at school, I've been sitting for endless
   hours hacking comfortably at home on my Linux box! It doesn't make the
   hours fewer, but it sure makes them more enjoyable! I've also been
   playing around with PostgreSQL 6.2 and MySQL RDBMS's and they have
   been a HUGE amount of fun and a great means of learning SQL and
   database design. When things here settle down a bit I'll be writing a
   bit about these.
   
   For my DiffEq class I finally broke down and purchased the venerable
   Mathematica 3.0 for Linux from the good folks at Wolfram Research.
   This has been a godsend and a wonderful toy to tinker with! I'll
   refrain from getting on the soap box about this one, but will say that
   it is a fantastic program and would HIGHLY encourage anyone in a
   mathematics-oriented discipline to invest in it. For the curious,
   here's a "hot off the press" screen-shot of what I've been up to this
   weekend: plowing through a DE take-home exam (and don't worry, our
   instructor, who's a delightful and brilliant guy, gave us the OK to
   use "whatever technology you have at your disposal..." :-)
   
   Here's the obligatory thumbnail: click on it to get the full (~88K)
   1024x768 effect - kinda like being there...!
   
   [LINK] 
   
   For the curious, this was the question about a damped oscillator whose
   angle of deflection was given by the equation:

        Ř'' + 0.25 Ř' + sinŘ = 0

   In which Ř is meant to be theta, the angle of deflection. The graph is
   the time series plot of the corresponding system of non-linear
   differential equations with starting values at (0,2), (0,3), and
   (0,4). Mathematica has been fantastic and, more to the point, they
   provide a Linux Student Version. If you're serious about wanting to
   see high quality software for Linux, then "speak with your feet" (or
   rather, your wallet :-). If I were doing the Tucows thing, these guys
   would get the whole herd!
   
   And finally, I've been doing a slew of X window based programming
   using Xlib and now Motif for my Computer Graphics course. Once again,
   Linux has meant being home at night rather than 40 miles away sitting
   in the student lab hacking on the X system at school. I've mentioned
   it before but it's worth repeating good praise: I bought RedHat Motif
   2.0 a couple years ago at the Linux Expo and haven't had a single
   problem with it despite a good deal of use. If you're shopping for
   Motif then I'd definitely have a look at this product. On the other
   hand, I've heard reports that the "Hungry Programmers" have been
   making serious strides in bringing the LessTif product to maturity.
   Here's a quote from a recent 0.81 distribution:


LessTif 0.81 has just been released.  LessTif is a freely available Motif
clone.  It is going to be source level compatible with Motif 1.2. It is
distributed under the terms of the GNU Library General Public License (LGPL).
LessTif is available from the following URL's


http://www.hungry.com/products/lesstif/

ftp://ftp.hungry.com/pub/hungry/lesstif/
or

http://www.lesstif.org/products/lesstif/

ftp://ftp.lesstif.org/pub/hungry/lesstif/

   I haven't had a chance yet to compile and install it but a number of
   programs, such as the latest DDD debugger, claim to be compilable
   using Lesstif.
   
  And Now For Our Feature Presentation...
  
   As I mentioned above, time has been a bit short here recently although
   over a short Fall Break a couple weeks ago I did manage to write up a
   short article for the Linux Journal on the Midnight Commander file
   manager. They have very graciously allowed me to include the full text
   of this here. This is the unedited, first-draft copy that was sent to
   them, so all the typos and other egregiosities are solely mine. I have
   long wanted to write about this fantastic file manager which, in my
   book, is a definite "must have" app on every Linux system. This is
   geared towards an introduction/overview, and while admittedly not
   encyclopedic, it does cover most of the highlights (I think... :-)
   Here it is:
   
  An Introduction to the Midnight Commander
     _________________________________________________________________
   
                              Closing Up Shop
                                      
   Again, I apologize for such a short column after so long a hiatus. As
   all of the graduating seniors will attest, the final semester usually
   packs quite a wallop and mine has been no different. Good news is, by
   the time you read this I'll be nearly done: GRE Comp Sci Subjects are
   on December 13th at 2:00 PM.
   
   And then... sleep :-)
   
   I'll be working with the good folks in Biomedical Informatics at the
   Vanderbilt University Medical Center here in Nashville for the
   following six months or so and then, hopefully, I'll be starting a
   Medical Informatics fellowship or MS program in Comp Sci somewhere. In
   the interim, I have a large and growing list of backlogged projects
   and things I'd like to read up on, tinker with, and learn about. By
   January, I'm hoping to have the Weekend Mechanic column back up to
   speed.
   
   My deepest and sincerest thanks to Marjorie Richardson and the rest of
   the crew at Specialize Systems Consulting who have worked
   extraordinarily hard at providing the Linux Gazette. Special thanks
   are also deserving to Mr. Richardson, who has shouldered the burden of
   "Linux Gazette Editor" this month!
   
   Finally, from our home to yours, we want to wish y'all a very
   wonderful and joyous Christmas Season.
   
   John & Faith Fisk
   Nashville, TN
     _________________________________________________________________
   
                               Mail Me a Note
                                      
   Got any comments, suggestions, criticisms or ideas?
   Feel free to drop me a note at:
   
   
    John M. Fisk <fiskjm@ctrvax.vanderbilt.edu>
    
   Document Information:
   $Id: wkndmech_dec97.html,v 1.3 1997/11/24 00:18:51 fiskjm Exp fiskjm $
     _________________________________________________________________
   
                       Copyright © 1997, John M. Fisk
         Published in Issue 23 of the Linux Gazette, December 1997
     _________________________________________________________________
   
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    "Linux Gazette...making Linux just a little more fun!"
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                              x3270 and Linux
                                      
                     By Chris Mason, h.c.mason@lmco.com
     _________________________________________________________________
   
   Everyday I have to logon to The MVS (Multiple Virtual Storage)
   Operating System and edit COBOL (Common Business Oriented Language)
   program source code. When I first started being a COBOL programmer in
   1985, we all used dumb terminals such as the IBM 3278. As time passed,
   people starting getting IBM PC compatibles and such things as IRMA
   cards were used to connect the IBM PC to the Mainframe and make it
   look like a dumb terminal.
   
   After receiving an IBM PC compatible myself, I added an extra SCSI
   harddisk and installed Linux. Using Linux's TCP/IP capability, and the
   driver for the 3COM ethernet card in the computer, I was able to
   connect Linux to the network.
   
   I began to try to logon to the IBM Mainframe. I found that there were
   several differences between the standard Telnet VT100 terminal model
   and the IBM 3270 terminals. I needed a new tool so that I could use
   the features of the IBM 3270 such as function keys.
   
   Fortunately, there are two tools to emulate the IBM 3270 type
   terminal. One is known as tn3270, and the other is x3270.
   
   X3270 is a program that is available with man Linux distributions and
   is available on ftp.x.org and other mirror sites.
   
   As a mainframe programmer, I have noticed the following advantages
   over a dumb terminal:
    1. x3270 can print the screen contents on a network printer and is
       easily configurable.
    2. Key strokes can be mapped to the 3270 keys.
    3. x3270 can operate under a script, or run a script, allowing
       automated logons and data entry tasks.
    4. There is a type-ahead feature. The dumb terminal won't accept
       extra characters, but linux will.
       
   X3270 comes with various resources that can be configured by the user.
   Here is contents of my .Xdefaults file apropos x3270:
! Set the font used in the x3270 screen:
x3270.emulatorFont:    3270-12
! Set the model of 3270 family terminal
x3270.model:   3
! Set the default print command:
x3270.printTextCommand: lpr -Psmb
! Set the keymap translation to use.  I found hp-pc to be the most
! compatible:
x3270.keymap:     hp-pc
! The below is a user keymap which allows me to override the
! default keymapping.  This way I can set the previous (page up)
! key to PF7 which is set to PREV on most ISPF edit panels,
! and page down to PF8 which is DOWN on edit
! EraseEOF is a function to erase a field to end of field
! here I map both ctrl delete and alt delete to this function.
x3270.keymap.hp-pc.user: \
   <Key>Prior:     PF(7)\n\
   <Key>Next:      PF(8)\n\
   Ctrl<Key>Delete:    EraseEOF()\n\
   Meta<Key>Delete:    EraseEOF()\n

   X3270 has several other features. One nice feature is the file
   /usr/lib/X11/x3270/ibm_hosts which contains a list of IBM hosts to
   appear on a logon menu.
   
   I would say that this is a great program and makes logining on to an
   IBM Mainframe a breeze.
   
   X3270 comes with manual pages and some documentation. Here are the
   copyrights from the x3270 manual page:
   
   COPYRIGHTS
   
   Modifications Copyright 1993, 1994, 1995, 1996, 1997 by Paul Mattes.
   Original X11 Port Copyright 1990 by Jeff Sparkes. Permission to use,
   copy, modify and distribute this software and its documentation for
   any purpose and without fee is hereby granted, provided that the above
   copyright notice appear in all copies and that both that copyright
   notice and this permission notice appear in supporting documentation.
   
   Copyright 1989 by Georgia Tech Research Corporation, Atlanta, GA
   30332. All rights Reserved. GTRC hereby grants public use of this
   software. Derivative works based on this software must incorporate
   this copyright notice.
     _________________________________________________________________
   
                       Copyright © 1997, Chris Mason
         Published in Issue 23 of the Linux Gazette, December 1997
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                          Linux Gazette Back Page
                                      
           Copyright © 1997 Specialized Systems Consultants, Inc.
For information regarding copying and distribution of this material see the
                              Copying License.
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  Contents:
  
     * About This Month's Authors
     * Not Linux
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                         About This Month's Authors
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    Wayde Allen
    
   Wayde Allen is an Electrical Engineer involved with the maintenance
   and development of the U.S. primary rf power standards at the National
   Institute of Standards and Technology (NIST). He has been using Linux
   as his primary computing platform for about three years, and was
   instrumental in the formation of the Boulder Linux Users Group.
   
    Larry Ayers
    
   Larry Ayers lives on a small farm in northern Missouri, where he is
   currently engaged in building a timber-frame house for his family. He
   operates a portable band-saw mill, does general woodworking, plays the
   fiddle and searches for rare prairie plants, as well as growing
   shiitake mushrooms. He is also struggling with configuring a Usenet
   news server for his local ISP.
   
    André D. Balsa
    
   André Balsa lives in France, 80 miles south of Lyon. He currently runs
   a small Internet consulting business. When not busy exploring Linux
   performance issues, Andrew likes to spend his time with his 1-year old
   daughter, or else try different French recipes on his friends. He also
   helped set up the Linux Benchmarking Project pages at
   http://www.tux.org/bench/. and a web site at
   http://www.tux.org/~balsa/linux/cyrix, about the use of Cyrix 6x86
   processors with Linux, which has had more than 9,000 visitors in less
   than two months uptime.
   
    Chris Baron
    
   Chris is employeed as IBM Mainframe COBOL Programmer at
   Lockheed-Martin in Sunnyvale, California. His e-mail is
   h.c.mason@lmco.com. He works as an IBM Mainframe COBOL Programmer and
   use an Application under linux called x3270. Perhaps others might be
   interested in using this program because IBM 3270 terminals are hard
   to come by.
   
    Jim Dennis
    
   Jim Dennis is the proprietor of Starshine Technical Services. His
   professional experience includes work in the technical support,
   quality assurance, and information services (MIS) departments of
   software companies like Quarterdeck, Symantec/ Peter Norton Group, and
   McAfee Associates -- as well as positions (field service rep) with
   smaller VAR's. He's been using Linux since version 0.99p10 and is an
   active participant on an ever-changing list of mailing lists and
   newsgroups. He's just started collaborating on the 2nd Edition for a
   book on Unix systems administration. Jim is an avid science fiction
   fan -- and was married at the World Science Fiction Convention in
   Anaheim.
   
    Carlie Fairchild
    
   Carlie Fairchild is an Advertising Representative and Marketing expert
   for Linux Journal.
   
    John M. Fisk
    
   John Fisk is most noteworthy as the former editor of the Linux
   Gazette. After three years as a General Surgery resident and Research
   Fellow at the Vanderbilt University Medical Center, John decided to
   ":hang up the stethoscope":, and pursue a career in Medical
   Information Management. He's currently a full time student at the
   Middle Tennessee State University and hopes to complete a graduate
   degree in Computer Science before entering a Medical Informatics
   Fellowship. In his dwindling free time he and his wife Faith enjoy
   hiking and camping in Tennessee's beautiful Great Smoky Mountains. He
   has been an avid Linux fan, since his first Slackware 2.0.0
   installation a year and a half ago.
   
    Michael J. Hammel
    
   Michael J. Hammel, is a transient software engineer with a background
   in everything from data communications to GUI development to
   Interactive Cable systems--all based in Unix. His interests outside of
   computers include 5K/10K races, skiing, Thai food and gardening. He
   suggests if you have any serious interest in finding out more about
   him, you visit his home pages at http://www.csn.net/~mjhammel. You'll
   find out more there than you really wanted to know.
   
    Mike List
    
   Mike List is a father of four teenagers, musician, printer (not
   laserjet), and recently reformed technophobe, who has been into
   computers since April,1996, and Linux since July.
   
    Giampaolo Montaletti
    
   The old Monty is living in Italy and is a 36 years old guy, working as
   an economist at the Regional association of the Chamber of Commerce in
   Bologna (do you know Rimini?). The old Monty is manager for many
   projects involving networks, intranets, electronic commerce and so on,
   many of them granted by European and national foundations. He like to
   eat, drink red wine and apple distilled calvados.
   
    Jesper Pedersen
    
   Jesper Pedersen lives in Odense, Denmark, where he has studied
   computer science at Odense University since 1990. He expects to obtain
   his degree in a year and a half. He has a great job as a system
   manager at the university, and also teaches computer science two hours
   a week. He is very proud of his "child," The Dotfile Generator, which
   he wrote as part of his job at the university. The idea for it came a
   year and a half ago, when he had to learn how to configure Emacs by
   reading about 700 pages of the lisp manual. It started small, but as
   time went by, it expanded into a huge project. In his spare time, he
   does Yiu-Yitsu, listens to music, drinks beer and has fun with his
   girl friend. He loves pets, and has a 200 litre aquarium and two very
   cute rabbits.
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                                 Not Linux
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   Thanks to all our authors, not just the ones above, but also those who
   wrote giving us their tips and tricks and making suggestions. Thanks
   also to our new mirror sites.
   
   While I'm passing out thanks I must include Amy Kukuk and Margie
   Richardson, who have done much of the work to get this issue out.
   Margie has been working hard to get me up to speed on this task, but
   I've still a ways to go. My professional background has been in the
   oil business as a geophysicist, where I usually worked on dumb
   terminals connected to IBM mainframes or Digital minicomputers. At
   home I've been a Macintosh man for many years, so learning Linux/Unix,
   vi and HTML all at once has been, shall we say, exciting.
   
   As Margie has indicated in the past, we share a passion for the
   outdoors which we satisfy via camping and motorcycling. With winter
   close upon us now my adult son, Keith, and I will likely turn to cross
   country skiing in favor of motorcycling. Although I've not done so
   lately, I also fly as a private pilot and am rated for both single
   engine land and sea planes.
   
   Turkey This last week of the month of November Margie and I indulged
   in that most American of pastimes--eating too much at the Thanksgiving
   table. We split cooking duties with my sister, Roxanne, who also
   hosted. The afternoon was grand, the food great, and we even came home
   with enough leftover turkey meat for several days worth of sandwiches.
   
   As a final note, Margie and I will be out of town for the Christmas
   holidays, so expect the next issue of Linux Gazette to be a little
   late coming out.
   
   Have fun!
     _________________________________________________________________
   
   Riley P. Richardson
   Editor, Linux Gazette gazette@ssc.com
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   Linux Gazette Issue 23, December 1997, http://www.linuxgazette.com/
   This page written and maintained by the Editor of Linux Gazette,
   gazette@ssc.com
