Apple Lisa Source Code and Docs

More or less precisely 5 years ago news broke that the Apple Lisa software had been handed over to the Computer History Museum and its software curator Al Kossow and was due to be open sourced in 2018. However, everything about this went dark and quiet, including Al Kossow’s introductory post on the subject, announcing the soon to be awaited for publication.

Not long ago, as all hope seemed to be gone, the publication was re-announced for 2023. But, as it happens, we haven’t to wait for next year, as there is now a software repository and an extensive trove of documents found on Bitsavers already! (No idea, if there’s even more to come.) The documents section is especially interesting, while the software section is (still) a bit obscure. (The firmware seems to be in blobs only, and the LOS-files are in a rather obscure “.a2r” format. See below.)

Here you are:

Here’s a nice introduction to the system by Bruce Daniels, “The Architecture of the Lisa™ Personal Computer” (Proceedings of the IEEE, Vol. 72, No 3, March 1984):

Update: The official “source drop” is announced for Jan. 19th, so there is more to come!


Regarding file formats: Source files seem to be provided mostly in one of the following two formats: DC42 and A2R. In case you wonder what these formats are:

Meaning, DC42 should be accessible using a Mac emulator, as DiscCopy was part of the OS distribution. For A2R images, there is an AppleSouce client software (free download), which runs on Mac OS 10.11 or better and lets you inspect these images and even export their contents as files. The AppleSouce client works with DC42 images as well!
(Select “Open Disk Analyzer…” from the File menu, select you disk image, click on the field with the disk label/title below the hex view to view the captured file structure, select “Export Disk Image Or Files…” from the File menu, then select “Export Disk Contents as Files”, proceed…)

(As may be inferred from some associated images showing disk labels, this is really more a collection of digitized disks that somehow found their way into this distant future than an organized source code repository.)