Preserving Apple II history, one disk at a time

January 6, 2016 5:12 AM

Apple II hacker 4am has cracked hundreds of disks, removing protection schemes and not only posting the unprotected software to the Internet Archive where it can be run in your browser, but also posting detailed and entertaining (to a certain mindset) descriptions of how he did it (click the "Download text" option on each item to read -- here's the one for BurgerTime). Jason Scott explains.
One such crack that's generally playable without learning many keys is Pac-Man (Datasoft version).
For news on new cracks and generally interesting related stuff, there's 4am's Twitter feed.

Pac-Man: from demo, press space to start. During game, A/Z move up and down, left and right arrow move left and right.

posted by JHarris (29 comments total)

I am astonished by this. Also that it doesn't seem to include the 2 games I misspent my youth playing: Star Blazer and Snake Byte.
posted by chavenet at 5:16 AM on January 6, 2016 [1 favorite]

Chapter 7: In Which I'd Like To Add You To My Professional Network Of Linked Catalog Sectors

Heh.
posted by tocts at 5:23 AM on January 6, 2016 [2 favorites]

My favorite bit from the 4am notes:

I'm beginning to suspect that this disk
is nothing more than an infinite series
of decryption routines with a game
bolted on as an afterthought.

posted by pulposus at 5:27 AM on January 6, 2016 [13 favorites]

Thank you, how marvelous. I lived and breathed this stuff through most of middle and high school and that elegant walkthrough brought it all back (hello again Locksmith and Copy II Plus, my old friends). Had to get rid of my Apple IIe years ago when we sold my mother's house, and as we were hauling junk to the curb I still remember flipping through box after box of floppies filled with cracked games, like a magnetized plastic card catalog of my adolescence. Saved a few things, though -- in a box somewhere I know I still have my ratty copy of Beneath Apple DOS. Maybe I'll fire a few of these up later.
posted by informavore at 5:39 AM on January 6, 2016 [2 favorites]

This is so dope. I had an Apple IIE in middle school and vividly remember that one X-mas break I spent eating cinnamon rolls & wearing my new Nike sweat suit while playing Spy Hunter, Mario Brothers, and Sabotage on endless rotation. I must have felt like a tiny god.
posted by Bob Regular at 6:12 AM on January 6, 2016 [11 favorites]

Right out of the gate, I can tell this is going to be fun(*). The branch at $6404 jumps into the middle of the next instruction, which confuses the monitor disassembler.

(*) not guaranteed, actual fun may vary
posted by Chrysostom at 6:48 AM on January 6, 2016 [2 favorites]

chavenet, this isn't a general collection of cracked Apple II games, but just those that 4am had a hand in cracking. You might be able to find your old favorites elsewhere on the internet.
posted by JHarris at 6:49 AM on January 6, 2016 [1 favorite]

I have suppressed most of what I learned of 6502 assembler and floppy disk controller arcana, but this is a lovely refresher. I found the notes for Mr. Do even better than Burger Time. Great stuff.
posted by Lame_username at 6:55 AM on January 6, 2016 [2 favorites]

Read through the crack details for Pac Man and spotted the self-modifying decryption code right away.
Then read this:

That's changing the decryption loop, specifically the XOR key. And I blew right past it.

** golf clap **
posted by plinth at 7:01 AM on January 6, 2016

At one point, the asimov archive hosted a mirror somewhere in South Korea. The mirror site had a tgz of the entire archive, which I promptly downloaded. It's probably been 5 years since I booted up an apple ][ or //c or //e emulator .. Now I wish I had the time to get back into it.

Growing up, we had an expansion card that helped copy disks (not crack) but danged if I can remember what it was. Supposedly read the disks at low-low level to find hidden sectors, bad sectors and other fancy tricks used as copy protection.
posted by k5.user at 7:04 AM on January 6, 2016 [3 favorites]

I found the notes for Mr. Do even better than Burger Time.

I have no idea how this disk even boots.

posted by filthy light thief at 7:04 AM on January 6, 2016 [1 favorite]

As someone who knows nothing about anything dealing with this, these are still fascinating and fun!

I'd love to see these combined with like some oral history or commentary "track" of the people who actually did these copy-protection schemes. To see their opinion of their work being thoroughly analyzed so many years later.
posted by mayonnaises at 7:04 AM on January 6, 2016 [2 favorites]

I absolutely love this kind of digital cat-and-mouse because, as the .txt files indicate, the levels of obfuscation-within-obfuscation-within-obfuscation extend from the remarkable to the truly pathological.

I wonder how many times the original programmers have come across a crack like this and provided their own 30-years-later feedback.
posted by delfin at 7:04 AM on January 6, 2016 [1 favorite]

JHarris: " chavenet, this isn't a general collection of cracked Apple II games, but just those that 4am had a hand in cracking. You might be able to find your old favorites elsewhere on the internet."

Yeah, I, ahem, know.

(I at first thought this was some Library of Applexandria but eventually figured it out.)
posted by chavenet at 7:09 AM on January 6, 2016

I'm the right age to have learned just a little Apple cracking, at least enough to trace boot loaders and work out non-standard sector headers and stuff. It's fun to go back and tickle that part of my brain again. What I appreciate about 4am's work is how meticulous and careful he is in documenting what he's doing. It's a bit like Ken Sherriff's writing on 60s-80s computing hardware, only for something even more ephemeral.

Modern copy protection is still a cat-and-mouse game. People in the industry tell me that even 24 hours of delay in a crack release makes a huge impact on revenue.
posted by Nelson at 7:33 AM on January 6, 2016 [1 favorite]

From Sneakers:

It's as if somebody said at the last minute, "Hey, all that nasty stuff we did with the RWTS, the custom disk encoding, the nibble checks, the self-modifying code, and the progressive integrity checking JUST ISN'T ENOUGH so could you please add a disk check too?" And the weary programmer rolled their eyes and said, "Sure boss, I can monkey patch it." Then they moved 3 bytes of real code to a subroutine labeled CAN_YOU_BELIEVE_THIS_SHIT_RIGHT_HERE and went home early to get drunk in the shower.

Golden.
posted by delfin at 7:48 AM on January 6, 2016 [4 favorites]

I did a lot of low-level Z80 and 8086/386 work back when, including quite a lot of delving around inside games and copy protection (for totes legit reasons, oddly) and low-level disk finagling. One of the disk projects included an automated directory level/file level/sector level copy feature, which had to detect and work on any remotely likely disk format in the market. Thus on occasion, over a surprisingly lone period of time, I found myself doing much the same sort of stuff as 4am documents.

The difference was I (mostly) had access to prototype hardware that could be re-engineered on request and stuff like in-circuit emulators, plus test equipment that could look at head signals, PLL outputs and the like. The ICEs were the best, basically CPUs where you could get inside and halt time, dump/change registers, trace executions, dump memory and so on, all in hardware and in ways that any software running on them couldn't possibly know about. (You want to check execution time against some external register/counter? Go ahead, we have control of both vertical and horizontal hold...)

And it was still head-bangingly hard, at times. I have nothing but respect for people who take that shit on without industrial-grade hardware help, let alone the twisted geniuses who came up with some of the copy-protection madness that unfurled across my VT220...
posted by Devonian at 7:57 AM on January 6, 2016 [4 favorites]

Still want to find a playable version of Grotto Run, which came on a SoftDsik disk and worked with a joystick and was the closest thing to a real game I had when my parents would only buy educational stuff.
posted by Space Coyote at 8:33 AM on January 6, 2016

Kind of disappointed that cracking Sneakers didn't involve Setec Astronomy.
posted by Halloween Jack at 8:39 AM on January 6, 2016 [6 favorites]

omg lode runner
posted by koeselitz at 9:30 AM on January 6, 2016 [5 favorites]

This is great.
posted by flippant at 12:36 PM on January 6, 2016

Modern copy protection is still a cat-and-mouse game. People in the industry tell me that even 24 hours of delay in a crack release makes a huge impact on revenue.

Yeah, these "people in the industry," I don't trust them. I don't believe they've run verifiable experiments about this, with a control or anything. I think most people will just buy the game, not because of altruism but because it's just simpler, especially if they're running Steam and buying means not having to worry about keeping track of disks. I think they measure it by counting times-pirated and assuming every copy is a lost sale, which is not true by any means. And sure, I don't have any figures to back this assumption up, but then the need for copy-protection is a long-held assumption that largely validates itself, and I tend look askance on those kinds of things.

And the result... just last night I was trying to run Atari ST Rogue in Hatari, having heard from its programmer that it has interesting features in no other version, in addition to obviously being the source of much of NetHack's graphics. And my character gets killed on level 2, and the game names him Software Pirate blah blah, and I don't know if it's because of the disk image I used, the open source Atari ST firmware or an emulation flaw, and a Google search turns up nothing, so to heck with trying to get it ironed out I have other things to do.

That game is 25 years old, and the copy protection is in service of a company (Epyx) that went bankrupt shortly after the game's release. People care about breaking copy protection on old Apple II games, but the Atari ST had a smaller community, so who knows if this will ever get sorted out.
posted by JHarris at 2:09 PM on January 6, 2016 [2 favorites]

At one point, the asimov archive hosted a mirror somewhere in South Korea. The mirror site had a tgz of the entire archive, which I promptly downloaded.

Incidentally, also largely mirrored on IA:

games
emulators
disk images

I can't seem to find the documentation section though, which has some of the more interesting bits, really.
posted by vibratory manner of working at 2:28 PM on January 6, 2016 [2 favorites]

Yeah, these "people in the industry," I don't trust them.

Completedly agreed. The people who repeat these stories about copy protection are positing a world in which people are so anxious to get the latest release, they'll pay $50-$70 (vs. $0) to get it a single day earlier. Meanwhile, over here in the real world, most people have more content (games, movies, etc) than they could ever get through, and if they are even mildly predisposed towards downloading a game without paying for it, 24 hours is absolutely nothing as far as waits go.

If people aren't buying your game, it's not the copy protection that wasn't good enough.
posted by tocts at 3:38 PM on January 6, 2016 [2 favorites]

That's fun, especially the descriptions because 6502 was my first computer (with x200 bytes of RAM, including the x100 bytes mapped to the display, which could be used for programs as long as you didn't write to the last byte thus triggering a linefeed). Thanks for the happy memories.
posted by anadem at 6:01 PM on January 6, 2016 [1 favorite]

Chrysostom:

(*) not guaranteed, actual fun may vary

I don't know about you but disassembling a binary, finding exactly the right offset, and inverting a JMP to bypass a CD-present check is definitely my idea of a crackin' good Saturday evening.
posted by iffthen at 12:17 PM on January 7, 2016 [1 favorite]

That game is 25 years old, and the copy protection is in service of a company (Epyx) that went bankrupt shortly after the game's release.

There's still a rightsholder, even if they don't know or care about the game. It may well be a bundle of distressed assets held by a bank somewhere, or an entrepreneur who monetises old copyrights by waiting for someone to violate them and suing them for massive damages.
posted by acb at 8:12 AM on January 10, 2016

Your comment does nothing at all to speak against my complaint, acb.
posted by JHarris at 2:42 PM on January 10, 2016

The annoying thing about these games is that they keyboard often suddenly stops working, and I can't figure how to make it work again. Or maybe that's just a Lode Runner-specific problem? Either way, who knows. Tried in Chrome and Firefox, same problem.
posted by koeselitz at 11:08 AM on January 22, 2016