Short:        lets progs read xpk-compressed files (bug-fix).
Architecture: m68k-amigaos

                                xData v1.1
                             xDataPrefs v1.1a

                         (C) Martin W.Scott, 1993.

                          (NB: Requires OS 2.0+)


xData  is a program that allows other programs to read xpk-compressed files
as  if  they were normal files.  It is similar to PP by Michael Berg, which
provided a similar facility for PowerPacked files.

However,  PP  caused  problems  on  my  system  (it  crashed),  and anyway,
PowerPacker  has  been  superseded  by the more powerful and extensible xpk
standard.   Unfortunately,  it takes a long time for data-handling programs
to  catch-up  and recognise the xpk standard, not to mention those programs
that can't read any compressed files.


How does it work
----------------
xData  patches  a  few  dos  routines to allow named programs to read xpk'd
files.   These named programs are called clients.  This is different to PP,
which  affected  ALL programs, and caused many incompatability problems (on
my system at any rate), which is why I decided on the client model.

Clients are added using the xDataPrefs program; when a client opens a xpk'd
file, the file is decompressed to the t: directory and the client reads the
decompressed  file.  When the client closes the file, the temporary file is
deleted (but it's not quite that simple -- see technical details).

This client arrangement might seem restrictive, but it guarantees (though I
don't  :) system compatability.  Most users only compress certain files and
use certain programs to read them, so these are the only programs that need
to use patched routines.  It allows you to use your favourite data-handling
programs  rather  than  xpk-ified versions, e.g.  you can use ViewTex where
before you had to use ShowIFF or PPMore (for PowerPacked files).


[full instructions in distribution]


History
-------
 v1.1a	- xDataPrefs: fixed stupid memory bug (wasn't freeing task-list).

 v1.1	- xDataPrefs:  major enhancement - now has task list so addition of
          new clients is simplified.

	- xData: now postpones deletion for 5 seconds (for reasons why, see
          technical details above).

 v1.0a	- xDataPrefs: fixed bug when entering name on empty list.

	- xDataPrefs: window now font-sensitive.

 v1.0ß	- initial release.


Contact
-------
I can be reached with comments, suggestions, bug reports, praise, money etc.
at the following addresses:

BEFORE END OF JULY 1993:

	Martin W. Scott,
	23 Drum Brae North,
	Edinburgh  EH4 8AT
	United Kingdom

AFTER END OF JULY 1993:

	Martin W. Scott, c/o 
	557 Great Western Road,
	Ground flat right,
	Aberdeen  AB1 7PA
	United Kingdom

OR BY EMAIL UNTIL END OF JULY 1993: mws@castle.ed.ac.uk