Apple II DOS Source Code Released

gbooch writes "The Computer History Museum in Mountain View, California, is not just a museum of hardware, but also of software. The Museum has made public such gems as the source code for MacPaint, Photoshop, and APL, and now code from the Apple II. As their site reports: 'With thanks to Paul Laughton, in collaboration with Dr. Bruce Damer, founder and curator of the Digibarn Computer Museum, and with the permission of Apple Inc., we are pleased to make available the 1978 source code of Apple II DOS for non-commercial use. This material is Copyright © 1978 Apple Inc., and may not be reproduced without permission from Apple.'"

They printed off assembler

[i kan reed]

Whatever your complaints about your job, at least debugging your code doesn't involve stepping through assembly on a pencil and paper virtual machine.

Legacy Support

[pubwvj]

I wish that Apple, and other companies, would create deep legacy support all the way back. Software from the Apple II should be able to run on the MacOSX and iOS. The computational power is there to do the necessary emulation.

Contradictory?

[innocent_white_lamb]

It's being "made available" but it "may not be reproduced."

How does that work, again?

Game disk images in licensed emulator bundles

[tepples]

Lately it has become common for companies that own copyright in decades-old video games to rerelease the games in an emulator that runs on a modern platform. If a video game for Apple II requires Apple DOS, the game's copyright owner has two options. It can license Apple DOS in order to distribute it as part of the game's disk image bundled with the emulator. Or it can change the emulator to use high-level emulation for the BASIC integration, file system, and RWTS (block device driver) that make up Apple DOS.

Re:They printed off assembler

[kylemonger]

It didn't involve pencil and paper for long on the Apple II. I remember reading about a step-trace 6502 debugger for the Apple II back then. I didn't have any money to buy it so I wrote my own (in assembler of course) to ease debugging of a video game I was writing. It wasn't a hard job; the 6502 instruction set is small and straightforward and the CPU only has three registers.

Re:They printed off assembler

[oldhack]

Reading 6502 assembly is easier than reading some of today's bloated and convoluted Java/Perl/FP/what-have-you code. It's not like the assemblies of modern CPUs with OOE, branch predictions, and all such complexities.

Also, from a technical perspective, publishing source for 6502 machine code wasn't that big a deal. You could recreate a reasonable assembly source from the machine code by spending some time with reverse assembler (unless the code does goofy things like writing over its code and such). In fact, Apple II monitor code had a nifty reverse assembler built in.

Re:Game disk images in licensed emulator bundles

[Anonymous Coward]

Have you considered the possibility that Apple simply wouldn't release the source code at all, if there were no copyright protection?

To keep companies from "hoarding," as you put it, would require a sort of negative copyright, where they are forced to escrow their source code for public release at the end of the copyright term (which would also need to be reduced). This is an interesting idea; if you want copyright protection, you have to vouch that you will release what is being protected at the end of the term. Sounds fair to me. If you don't like it, you'll have to rely on trade secrecy instead.

Re:They printed off assembler

[NormalVisual]

In fact, Apple II monitor code had a nifty reverse assembler built in.

I'm sure there are a lot of us that remember "CALL -151"... :-)