Re: Filecracking Joust?

[Hot Rod <hotrod.apple2@gmail.com>]

On Thursday, April 4, 2013 2:34:49 PM UTC-5, Sean Fahey wrote:
> On Thursday, April 4, 2013 1:44:25 PM UTC-5, qkumba wrote:
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> 
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> > I just uploaded the one-file version ("joust 26k one file") to Asimov (the two-file version is there already ("joust 26k file")), but I don't know when it will become available.
> 
> > 
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> > I used aPLib in both cases.
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> 
> 
> Is there a paper, journal, video or crackto on how you guys do these compressions and conversions to ProDOS? I'd like to learn how its done. I'm amazed no one was widely doing it back in the day - was it just because the right tools didn't exist?

Although Lempel-Ziv (or Ziv-Lempel, if you prefer) compression was known in the 1980's (the original papers were published in 1977 and 1978), compression itself wasn't widely used. For 8-bit Apples, the most common was some form of run-length encoding. Even the 'picture packers' used at the time were still RLE-based, just customized to make better use of the Apple's unusual screen layout.

Dalton's Disk Disintegrater [sic] made a large step forward, but I *think* it used Huffman encoding (and probably some RLE mixed in), but that's just a guess.  It's possible it used an early stab at LZ-based.  (BTW, anyone ever know whatever happened to 'Dalton'?  Never knew who it was.)

But other than getting things into file form, and being able to move the program bits back into place in memory, doing additional compression on the code just never entered the scene.  Pictures were often compressed, to make them fit into files, but not whole programs.

An LZ-based tool would have been very handy back in the days of 300/1200 baud, for sure.  But, the right tools just didn't exist.

]HR