








                             iHPFS
                    An HPFS Driver for DOS
             Copyright (C) 1993-1997 Marcus Better

                         Version 1.26
                       November 18, 1997









Overview
========

iHPFS makes it possible for OS/2 users to use their HPFS partitions
when they boot plain DOS.  The HPFS partition is assigned a drive
letter, and can be accessed like any DOS drive.  iHPFS is restricted
to read-only access.

iHPFS is easy to install and convenient to use, as it acts like any
DOS drive.  Data files and programs on the HPFS partition may be read
and executed, or copied to other drives.


License
=======

iHPFS is free software, and is distributed under the GNU General
Public License.  Please see the file COPYING for details.


System requirements
===================

In order to run iHPFS, you need a 386 processor or better.  iHPFS runs
under MS-DOS and PC DOS 3.10 and later, DR DOS 5 and 6, Novell DOS 7
and OpenDOS 7.


How to use iHPFS
================

Run IHPFS.EXE from the DOS prompt.  The syntax is:

    	IHPFS [options] [d:n d:n ...]
    or	IHPFS /U [d:]

The brackets indicate an optional parameter.

d:      The drive letter that you want to assign to an iHPFS drive.
        You may specify more than one drive letter on the same command
        line.  If no drive letters are specified, iHPFS will scan your
        hard drives and automatically install all HPFS partitions.

n       The number of the HPFS partition that you want to access.
        HPFS partitions are numbered (logically) so that you can
        specify to iHPFS which partitions you want to access.  The
        first HPFS partition on the first hard disk is partition
        number 1.  Note that only HPFS partitions are counted - if
        your system has two HPFS partitions, they will have numbers 1
        and 2, regardless of any other non-HPFS partitions you might
        have.

iHPFS recognizes the following options:

/B1     Use a certain BIOS extension to access large drives.  Please
        read the section `Large IDE Drives' before using this option.

/B2     Disable use of the IBM/MS Extensions, another BIOS extension
        for large drives.  If you have problems running iHPFS, you can
        try this option.  It is only needed if you have a strange
        BIOS.

/C=x    Set up a cache in XMS memory.  A cache can improve performance
        tremendously.  x specifies the cache size, in KB, and is not
        optional.  To use this option, you must have an XMS driver
        like HIMEM.SYS loaded.

/L      This option makes it possible to access files with long
        filenames.  These files will be given a new filename and
        extension.  The new name will consist of the first valid
        characters (eight or less) before the first dot in the long
        filename.  The extension is computed from the long filename,
        and is made up of letters, digits and a few other characters.
        Filenames that begin with a dot will be seen as HPFS.xxx,
        where xxx is the computed extension.

/M      Disables multitrack operations.  When this option is given,
        iHPFS will not perform BIOS calls that read sectors from
        several tracks at once.  This option may be necessary if your
        BIOS cannot handle multitrack operations, and should only be
        used if iHPFS does not work otherwise.

/U      Uninstalls one or more iHPFS drives.  If no drive letter is
        specified, this will uninstall all iHPFS drives, and remove
        the driver from memory.  If a drive letter is specified, only
        that drive will be removed.

        If another TSR has been loaded after iHPFS, it may not be
        possible to uninstall iHPFS comletely in a safe way.  In those
        cases, a few bytes of iHPFS' code will remain resident,
        although inactive.


Examples
--------

To install iHPFS for all HPFS partitions, type

    	IHPFS

To install iHPFS for all HPFS partitions with long filename support
and a 128KB cache, type

    	IHPFS /L /C=128

To install only HPFS partition 2 as G:, type

    	IHPFS G:2

To remove iHPFS drive G:, type

    	IHPFS /U G:

To uninstall iHPFS completely, type

    	IHPFS /U


Setting LASTDRIVE
=================

If you get the error message "Out of drive letters" from iHPFS, you
need to make more drive letters available.  This can be done by
placing the line

    LASTDRIVE=Z

in your CONFIG.SYS file.


Large IDE drives
================

There is a problem with accessing IDE (ATA) drives larger than 528MB
(528 million bytes).  The problem arises on some configurations when a
partition occupies any cylinders numbered 1024 or higher.  iHPFS can
access these partitions if the BIOS supports it.

If iHPFS cannot access some of your HPFS partitions, you can try to
run iHPFS with the /B1 option.  This tells iHPFS to use a certain BIOS
extension which is available on many BIOSes.  If the /B option causes
problems, then simply refrain from using it.  In particular, the /B
option may not work with Windows95.

If some of your partitions cannot be accessed because the BIOS support
is missing, there are a few possible remedies.  The solution can be to
obtain a newer BIOS from the manufacturer.  In some cases, a software
driver for the EIDE card can be used.  It might also be tempting to
experiment with various BIOS configuration settings.  However, this
can cause the sectors on the disk to be shuffled like a deck of cards,
resulting in loss of data.  Be sure to backup first.

If you cannot access some partitions, you can download the program
HPFSINFO from the iHPFS homepage.  It prints some useful information
to a file, which you can send to me.


The future of iHPFS
===================

Many users have asked if there is going to be a read-write version of
iHPFS.  I have decided not to make such a version.  The primary reason
is lack of time.  Another reason is that I think it would very unsafe
to run such a program from DOS, because the risk of data loss in the
event of a crash is too large.  Please do not write to me to complain
about this.

I do not plan to add any new features to the program, but will attempt
to fix any remaining bugs and problems.  If you make any modifications
to the program, you are welcome to send them to me for inclusion.


Contacting the author
=====================

You are welcome to send me any ideas, comments and suggestions for
iHPFS.  If you have found any bugs, please let me know.  My email
address is

	Marcus.Better@abc.se

The latest version of iHPFS is available at

	http://www.student.nada.kth.se/~f96-bet/ihpfs/
