Short:        A compressing disk device v37.8; uses XPK
Uploader:     rhialto mbfys kun nl (Olaf Seibert)
Type:         util/pack
Architecture: m68k-amigaos

RCSId: $Id: README,v 1.5 1995/04/08 20:23:48 Rhialto Exp $

Overview
********

   `xpkdisk.device' is an exec-style device that looks like
trackdisk.device and similar disks. The difference is that it compresses
its data and stores it in multiple files in an existing filesystem.

   * Version 37.8 works around a horrible bug that is really caused by
     XPK when track files are not compressible.  Look in the source
     file "devio.c" for details, near the symbol XPKBUG.

     The bug was pointed out to me by Ulrik Jensen <uj2001@hdc.hha.dk>.

   * Fixes a bug in xdClear which assumed that all partitions started
     at track 0.

     The bug was pointed out to me by Michael Barsoom
     <mbars@bluejay.creighton.edu>.

   * You can now change the XPKD: assign on the fly, if you're careful.

   * xdClear now works with the fake scsi.device, which does not seem to
     know about ETD_* commands.

   * Now keeps the old track file while writing a new one. The old
     track file is only deleted after successfully writing the new one.
     You have more control about what to do in such situations.

   * Now includes a utility to reclaim space from deleted files.

   * Now uses a hierarchical track naming scheme for faster access!

   * Now behaves better in cace of threatening lack of disk space.

   * Now handles read-only media.

   It uses the XPK (eXternal PacKer) standard to do the actual
compression.  This has many advantages:

   * You can choose which compression is most effective for your
     purpose. For one disk, you might want a very tight compression
     that is slow, for another you may prefer a faster but less
     efficient compression.

   * As soon as another XPK library is released, you can use it for your
     compressed disk(s).

   * Because each track is a standard XPK-compressed file, you can use
     the normal XPK utilities to uncompress your data, should you wish
     to do so.

   * You can change the compression type of a disk on-the-fly. All
     already compressed data remains perfectly usable, but upon
     re-compression your new choice will be used.

   * You can even manually decompress and recompress your disk (when
     xpkdisk is not accessing it, of course) with another compression
     method.