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Knight Rider
Registered: Mar 2005
Posts: 114 |
If it were 1987 again....
I was watching Robin's video https://youtu.be/yVtKKb3wkYc regarding cracking from an original cassette. And it stirred a little interest in me again. To be honest I can't even remember how now but I cracked Wizball from original cassette using a Trilogic Expert (2nd version with botched ESM daughter board) and very likely V2.9 of the monitor software.
I did this again now on real hardware (as I wasn't having much luck with WinVICE 3.7), just for laughs and to try to stir up memories of way back then. Defeating Freeload now was much easier for me than back then.
I used the following packers:
MCC Compressor
then
Card Cruncher V4 (no idea who lent me this cartridge, but probably Tork&Torky)
(usual one was Matcham Time Cruncher V3.1 or a hacked version which ended up becoming Time Cruncher V3.1)
I ended up with 182 blocks incl. intro in Wizball
So it leads me to the next question, back in the day (for me) the best cracks had the smallest disk block size.
What packers did you use then on a real C64 in 1987, and what would you use now on real hardware (a. released upto 1987 and then anytime). What block size can you achieve ?
Exomizer V3.02 gives 144 blocks when no additional parameters are given.
TRIAD Wizball + is 166 with intro
Krejzi Packer $005E-$FFFF + Matcham Time Cruncher V3.1 gives 161 blocks
MCC Compressor + Matcham Time Cruncher V3.1 gives 165 blocks
Beast-Link/64k + Byte Boiler 256k V1.0 gives 148 blocks
Byte-Buster V4.1 + Byte Boiler 256k V1.0 gives 148 blocks |
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Martin Piper
Registered: Nov 2007
Posts: 634 |
I already did all of that in the videos. The two original tapes result in identical code and data at the point it starts the game code at $6389. |
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Mason
Registered: Dec 2001
Posts: 459 |
Hmmm I don't remember that the version with Imagine loader was frozen
I have to admit I haven't looked at the game for many years |
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Fungus
Registered: Sep 2002
Posts: 617 |
Yeah it doesn't seem like it is, but it most certainly is. |
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Martin Piper
Registered: Nov 2007
Posts: 634 |
It's not really frozen. It depacks a lot. But it jumps into the standard game start code at 6389 just like the original uncompressed load. The game start at 6389 does all its initialisation so it doesn't rely on the decompression ZP IO state. |
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Weetibix
Registered: Aug 2023
Posts: 1 |
The Final Super-Compressor was the packer that changed the compression playing field in my own experience...before this I'd only come across "char packers". I'm guessing the selection options offer some form of RLE, LZW & Huffman implementations wrapped up in one. The scene changed quickly with the arrival of Matcham's Time Cruncher V3.1/V4 and the illusive 1001 Card Cruncher (never had it).They were followed by many more excellent and improved alternatives over the years (Cruel Cruncher, Bit Imploder, Exomizer, etc). It was always a balancing act between adding a cracktro vs final compressed file size.
So it leads me to the next question, back in the day (for me) the best cracks had the smallest disk block size.
What packers did you use then on a real C64 in 1987, and what would you use now on real hardware (a. released upto 1987 and then anytime). What block size can you achieve ? |
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Fungus
Registered: Sep 2002
Posts: 617 |
On the real thing, I would probably try to port Exomizer to the C64.
I'd definitely use my own packer now.
I'd have to figure out how equal sequence and lz works to try and make my own, but I'm sure I could if I got obsessed with it.
I can code my own Huffman as well, which might be interesting for certain things.
In 1987, I'd probably use Squeezer, and Sledgehammer. Since Byteboiler and Cruncher AB weren't available yet. |
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Bansai
Registered: Feb 2023
Posts: 34 |
Quoting FungusI'd have to figure out how equal sequence and lz works to try and make my own, but I'm sure I could if I got obsessed with it. It's fun to mess with, my favorite part being the "aha" moment when you see how patterns like ABCABCABC... can decompress on the fly in place without the whole string already being present in memory and with only a single length+distance pair referring back to where the sequence starts. Articles on the byte-based LZ77 are a good starting point for learning LZ. You could teach yourself very quickly.
Interestingly, LZ77 still sees modern usage in LZ4. Exomizer beats LZ4 with respect to compression ratio, but LZ4 was largely designed for raw speed balanced against good enough compression, not best case compression. |
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cbmeeks
Registered: Oct 2005
Posts: 72 |
I wished it was 1987 again. I would be 14. |
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tlr
Registered: Sep 2003
Posts: 1714 |
Quoting FungusOn the real thing, I would probably try to port Exomizer to the C64.
If it is to approach the gain of the regular exomizer compression would be prohibitively slow. The optimization routine for the length/offset encodings takes quite some CPU time on a modern machine.
You could of course make a version that uses the exact same depacker but produces less optimal compression. It might not gain much (if at all) over Byteboiler, Cruncher AB and friends, but it would still be much faster depacking. |
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Fungus
Registered: Sep 2002
Posts: 617 |
Yeah it does, probably take months on a c64, but just for fun with REU. |
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