Computer History Museum Releases Apple II DOS Source Code
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.The Apple II, which first began shipping in 1977, came as a ready-to-use computer equipped with a keyboard, compatible with any display monitor. Priced at $1,298, it also featured color, graphics, expansion slots, game paddles, and had the BASIC programming language built-in.
The Apple II DOS source code was developed by Paul Laughton, a contract programmer from Shepardson Microsystems, who wrote DOS on punch cards over the span of seven weeks after Apple paid $13,000 for his services.
"DOS was written on punch cards. I would actually hand-write the code on 80-column punch card sheets. A guy at Shepardson named Mike Peters would take those sheets and punch the cards. The punch cards would then be read into a National Semiconductor IMP–16 and assembled, and a paper tape produced.The source code is downloadable directly from the Computer History Museum website, and comes with meeting minutes between Apple and Shepardson Microsystem, plus contracts and scanned lineprinter listings from 1978. The Computer History Museum also has a detailed history of the creation of Apple II DOS, which is well worth a read.
The paper tape was read into the Apple II by a plug-in card made by Wozniak, and I would proceed to debug it. As the project got further along and the code was all written, and it was debugging and updating, I would mark up a listing and give it to Mike Peters who would then change whatever was necessary and deliver me a paper tape and I'd start again."