From: James_Hastings-Trew@telepro.UUCP (James Hastings-Trew)
Newsgroups: comp.sys.amiga.graphics
Subject: Re: double hard drive capacity??? NOT
Distribution: world
Date: 15 Sep 92 17:50:48 CST
Organization: TelePro Technologies

In a message dated Tue 15 Sep 92 12:41, 10667547@eng2.eng.monash.edu.au (ji
wrote:

 > Slight correction.  It's called XPK, version 2.3
 > It will be free-ware at the end of the month and will be available from
 > FTP.
 > Someone said I could BMS it from them, but I'm dumb and don't know what
 > BMS
 > is.  Guess I'll have to wait until the end of the month....
 > This information is second hand...  Perhaps it should become an FAQ, as
 > I 
 > asked for such a program a while back too....

 > Jim

I downloaded XPK last week from a bulletin board. Can't remember which one
off hand.

Anyway, here is the skinny:

XPK consists of a number of compression libraries, a patch for LoadSeg, and
a handler for a special type of device that can contain compressed files.
It also has a few C: commands for compressing and de-compressing files.

First of all, the compressors are VERY fast - as fast as LHA, and nearly as
efficient. The decompressors are blazingly fast. I compressed a 1 meg
executable (Imagemaster) down to half size. The normal one takes 11 seconds
to load. The compressed one takes 8 seconds.

When accessing files from the specially mounted device, compressed files
are totally transparent to the operating system. For example, you can
compress an ANIM file, and then use any standard VIEW program to look at
it. As long as you approach the files through the mounted device, and not
through the normal path, the decompression is completely transparent.

For example, if you have a directory on dh0: called "Stuff" and you created
a XPK device from that directory as so:

Assign XFH0: dh0:stuff
mount XH0: 

if you enter the directory like so:

cd dh0:stuff

the files will appear to be compressed, and unavailable to your
applications. If you enter the directory like so:

cd XH0:

then the files will be transparently decompressed for you as you look at
them, copy them, use them, etc.

If you copy a file from dh0:Stuff to RAM:, you'd get the compressed
version. If you copy a file from XH0: to RAM:, you'll get the original.
It's neat!


Executables that are compressed can be run from any directory. The caveat
here is that any files which use overlays cannot be successfully compressed
and used - same with any of the Powerpacker and Imploder type programs.
That means that Imagemaster CAN be crunched, but Dpaint_4 or ProDraw cannot
be.

The other thing that is a small drawback to this scheme is that I would
like to have files automatically compressed when placed in the special XH0:
volume, but they are not. You have to use a CLI command to crunch the
files.

I have been using XPK on my system for a few days now, and find no problems
with it, no slowdowns, and I am generally delighted with it's performance.
Kudos to the authors, and I look forward to more functionality in the
future (i.e. automatic re-compession of saved files).

-- Via DLG Pro v0.992

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Telepro!james_hastings-trew@access.usask.ca
"[Democratic philosphy consists of] the idea of running your paycheck
through the salad shooter and dumping the shreds on the compost heap of
good intentions." -P.J. O'Rourke in Bill Clinton, The Rolling Stone
Interview
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