The Computer History Museum
announced today that it has -- in collaboration with the Digibarn Computer Museum and with permission from Apple -- posted the historic original 1978 source code for version 3.1 of the Apple II DOS
Disk Operating System." Also included with the source code are several historical documents laying out the course for the OS, as well as some minutes of a post-delivery meeting discussing the release and future of the product.
Paul Laughton, a contractor for Shepardson Microsystems, wrote the Disk Operating System for the Apple II in only seven weeks, and Apple delivered it to eager customers in June of 1978 with the Steve Wozniak-designed floppy disk controller using only eight integrated circuits; revolutionary for the time. The source code being released by the museum today are scans of two listings and additional material that Paul had kept in his home office for 35 years.
"There was an amazing 'can-do' attitude among the engineers working on the early PCs in the 1970s and 1980s," said Len Shustek, museum chairman. "Projects which would have taken years inside large companies were done in weeks or months. It is inspiring to see what they were able to do, with primitive tools, on computers that were tiny relative to today's."
"We are grateful that engineers like Paul are pack-rats, and preserve history that might otherwise be lost", said John Hollar, The Computer History Museum's President and CEO. "And we thank Bruce Damer of the Digibarn Computer Museum for collaborating with us to rescue these important artifacts. The preservation and release of this code is part of our ongoing commitment to software history, and we're delighted to bring it to the world."
Of the 70s-era project, Laughton said that "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 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."
Seven documents have been made available, with four of them being source code to the release, one technical document about the 5.25-inch disk drive, one detailing "contracts and addenda" between Apple and Shepardson, and the last detailing meeting minutes about bugs and enhancements to the software.