DSKXTRCT and DSKCOMPR - Version 1.2 - 7/4/1998
Copyright 1997, 1998 by Alan B. Arnett
Updated 2003 by Lars Erdmann
Contact: Jon Saxton (js@triton.vg)


Program summary


The DSKXTRCT and DSKCOMPR programs work with DSK diskette image
files associated with the IBM programs, SAVEDSKF and LOADDSKF.
(See documentation for a brief explanation of the SAVEDSKF and
LOADDSKF utilities.)

DSKXTRCT extracts the original files from DSK files into a
subdirectory, avoiding the need to recreate diskettes. This is
useful if the desire is to copy the original files onto a hard
drive without creating intermediate diskettes.  One of the major
purposes for DSKXTRCT is to create a hard drive subdirectory
directly from IBM fixpak DSK files that can be used to apply the
fixpak, bypassing the creation of diskettes.

DSKCOMPR compares the files in DSK files to a target subdirectory
or diskette. This is useful for verifying that LOADDSKF correctly
created the diskette.  The compare of a DSK file to a diskette is
a case where DSKCOMPR fills a need not satisfied by LOADDSKF.

DSKXTRCT was written to fulfill two needs.  First, to eliminate
the need to create diskettes from IBM fixpak DSK files.  With
DSKXTRCT, a subdirectory containing the original files can be
created directly from the DSK files and the SERVICE process then
can be changed to use this subdirectory.  Second, to enable the
storage of product diskette backups on large storage media such
as ZIP or SYQUEST drives using the SAVEDSKF program and still
have access to the original files when needed without having to
recreate the diskettes.

DSKCOMPR was written as a companion program, as a result of bbs
exchanges/complaints about diskette errors that sometimes went
undetected when LOADDSKF recreated fixpak diskettes.

2003, Lars Erdmann: I have enhanced the program to be able to
process disk images that were produced without leader, I think
(savedskf /D, possibly in combination with /A which is necessary
to produce an image that loaddskf can handle,
according to the savedskf documentation).
This was necessary for some fixpaks/updates that IBM delivers
(for example: WG*8425.1DK,WG*8425.2DK, the 16-bit MPTS fixpak).
Since the CRC info is missing
(because that one normally is placed in the leader),
CRC checking is skipped/ignored for that type of files.


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