Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!mintaka!ogicse!usenet!jacobs.CS.ORST.EDU!parkern
From: parkern@jacobs.CS.ORST.EDU (Neil Parker)
Newsgroups: comp.sys.apple2
Subject: Re: uncompress for the Apple2?
Summary: ?OUT OF MEMORY, PROGRAM TOO LARGE, NO BUFFERS AVAILABLE, etc.
Message-ID: <1991Apr07.101949.26725@lynx.CS.ORST.EDU>
Date: 7 Apr 91 10:19:49 GMT
Article-I.D.: lynx.1991Apr07.101949.26725
References: <1991Mar31.235843.21088@wpi.WPI.EDU> <1991Apr3.223420.4213@world.std.com> <4497@mint17.UUCP>
Sender: @lynx.CS.ORST.EDU
Reply-To: parkern@jacobs.CS.ORST.EDU (Neil Parker)
Organization: The Universal Society for the Prevention of Reality
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In article <4497@mint17.UUCP> wilner@motcid.UUCP (Corey S. Wilner) writes:
>lucifer@world.std.com (Kevin S Green) writes:
>>In article <1991Mar31.235843.21088@wpi.WPI.EDU> gerardo@wpi.WPI.EDU (Gerardo Leute) writes:
>>>Is there a utility that will uncompress files using the adaptive Lempel-Ziv
>>>coding system?  I would like to use the unix 'compress' command to make files
>>>smaller, downloading them, and then uncompressing them on the Apple (gs).
>>Gerardo,
>> Get GSShrinkit v1.04 by Andy Nicholas. A good FTP location is
>> tybalt.caltech.edu.
>Is there such a beast for the Apple //e.  I too would like to compress some UNIX
>files before grabbing them with my Apple.  Does Shrinkit 3.2.3 do the job?

Alas, there will probably never be such a beast for the standard Apple //e
(i.e. one without lots of memory expansion cards).

The problem is that Lempel-Ziv is a major memory hog.  It works by building
a huge dictionary of strings, and building a dictionary big enough to
match UNIX compress requires far more memory than most //e's have (over
400K, in fact).

The reason Shrinkit can do Lempel-Ziv on an Apple //e is that it doesn't
try to match UNIX compress...it uses a dictionary small enough to fit into
the Apple's memory.  If the size of the UNIX compress dictionary were
similarly restricted (which is fairly easy to do--use "compress -b12"), it
would theoretically be possible to uncompress the resulting file on an
Apple //e (unfortunately, to the best of my knowledge, nobody has yet
written a program to do so.)

               - Neil Parker
--
Neil Parker                 No cute ASCII art...no cute quote...no cute
parkern@jacobs.cs.orst.edu  disclaimer...no deposit, no return...
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