I got my DOS PC on #GlobalTalk so I’m going around printing greetings to people’s printers from Deluxe Paint!

[colin_mcmillen@piaille.fr]

@polpo A very good example of "what seems illegal but isn't"

[polpo@chaos.social]

@MuseumJoe I didn’t see your zone in the picker!

[paulrickards@mastodon.social]

@polpo Oooh, will you be cloning this card next? I hope?

[polpo@chaos.social]

@paulrickards it’s funny, this card has the same core chips as the ImageWriter II LocalTalk Option card (6502, SCC, ROM, RAM, 74xx glue) so it’d be pretty easy to clone!

[philnelson@xoxo.zone]

@polpo spicy

[mos_8502@studio8502.ca]

@polpo @paulrickards Every clone brings us closer to truly owning our platforms.

[billgoats@bitbang.social]

@polpo that text-only chooser is blasphemous and beautiful

[polpo@chaos.social]

@paulrickards actually I just realized it also has a couple PALs so those will have to be reverse engineered

[mos_8502@studio8502.ca]

@polpo @paulrickards Can they be dumped or not that kind of chip?

[billgoats@bitbang.social]

@polpo @paulrickards Doooo it! ️

[polpo@chaos.social]

@mos_8502 @paulrickards there are tools now that can be used to reverse engineer the equations from them, even if they’re read protected!

[gloriouscow@oldbytes.space]

@polpo @mos_8502 @paulrickards

automatically?

I saw a post that implied that you could derive the equations for registered PALs by exhaustively searching the inputs and clocking the PAL as many times as it has registers for each input increment, but I am not entirely sure what can take that and produce equations

[polpo@chaos.social]

@gloriouscow @mos_8502 @paulrickards I don’t think fully automatically, no. The project I’ve heard the most of is @hkz’s DuPAL: https://github.com/DuPAL-PAL-DUmper

[gloriouscow@oldbytes.space]

@polpo @mos_8502 @paulrickards @hkz

I came up with this idea before I knew that @hkz had essentially done the same thing with https://github.com/DuPAL-PAL-DUmper/dppeeper

but the idea I had was to let you define what you can learn from tracing out a board so you can give pins reasonable names while twiddling them interactively.
This has been a huge help in reverse engineering the Seequa Chameleon which is positively lousy with registered PALs

This currently uses a T48 but it obviously has some limitations - I hope to add support for the dupal dupico board

[gloriouscow@oldbytes.space]

@polpo @mos_8502 @paulrickards @hkz

there are basically full circuit diagrams of every PAL available in the old Data I/O manuals. I'm wondering if being able to visualize the fuse map and registers would be an insane idea or not.

I think if you have some educated guesses about what the PAL does that could probably eliminate a ton of the brute force work required to derive the equations - just knowing that the Germans were talking about the weather helped crack Enigma, after all.

shame someone smarter than me isn't trying to do this lol