Commodore 128 Programmer's Reference Guide (PDF)
Commodore Plus/4, C116, C16 (TED) Technical Documents

The Commodore Plus/4, the C16 and the C116 from 1984 were members of the 6502-based “TED” series, named after the 7360 TED (“Text Editing Device”) video controller. The TED systems were basically the low-cost cousins of the C64: The overall system architecture and the video chip are very similar to the C64’s, but they lack certain features like hardware sprites. On the other hand, there are some added features like extra colors and more control over the internal timing of the video chip.
HFS+ File System Analysis and Forensics with fileXray
Modern filesystems are highly optimized database systems that are a core function of modern operating systems. They allow concurrent access by many CPUs, they keep locality up and fragementation down, and they can recover from crashes guaranteeing consistent data structures.
Amiga intern (PDF)
(German) Die Qualität dieses Scans ist furchtbar, aber wenigstens ist die PDF durchsuchbar.
Apple Copland Reference Documentation
The Copland project was Apple’s ill-fated attempt in the mid 1990s to replace the aging classic Mac OS with a more modern operating system that had a microkernel, virtual memory and preemptive multitasking. Information on Copland is scarce, therefore I have compiled 20 hard to find Copland reference documents, as well as the 359 page book “Mac OS 8 Revealed”.
Apple Lisa Operating System Reference Manual (PDF, 1983)

The Apple Lisa from 1983 was the first consumer-class computer with a graphical user interface and significantly more advanced than the 1984 Macintosh, which had a similar UI, but a comparatively primitive underlying OS. Here, I present a searchable PDF of the rare “Operating System Reference Manual for the Lisa” (1983), as well as a quick overview of the OS and how it compares to UNIX.
Tripos, the Roots of AmigaDOS

The core of the Amiga Operating systems consists of the three major components Exec (scheduling, memory management, IPC), Intuition (GUI library) and AmigaDOS (process and file management). AmigaDOS is based on the Tripos operating system which Commodore bought because development of their own DOS subsystem failed to meet deadlines. In this article, I am presenting searchable PDFs of the very rare Tripos manuals (638 pages) as well as the AmigaDOS manual (304 pages). Comparing the two documents will share some insight in the relationship between Tripos and Amiga OS.
Archimedes Operating System (PDF)
Inside Macintosh Volumes I, II, III (PDF)

Here are all three volumes of the original 1985 edition of Inside Macintosh as a searchable PDF:
64'er 04/1984 (PDF)

I converted the first issue of the German Commodore 64 magazine 64’er into a searchable PDF:
Transactor November 1987: Volume 8, Issue 3 (PDF)

The other day, I found this at WeirdStuff: