Given the tendency of websites to disappear over time, I archive sites that I find particularly helpful.
wget -mpck -U "" -e robots=off -w 1 -X "/projects/genealogy" http://web.frainresearch.org:8080
Consolidates large amounts of information on Q-bus modules into comparison tables. Also contains details of a sample PDP-11/73 build including custom PCBs to interface an ATX power supply and provide front panel functions.
SIMH, Trailing Edge
wget -mpck -U "" -e robots=off -w 1 http://simh.trailing-edge.com
The homepage of SIMH also contains information on DEC processors such as the J-11/F-11/T-11, including stories from the designers and low-level details like microcode listings, technical papers about historic computer systems, and software kits for use with SIMH.
UNIX 7th Edition Manual - Volume 2
wget -mpck -U "" -e robots=off -w 1 -X "*" -I "/bsd/7thEdManVol2" https://wolfram.schneider.org/bsd/7thEdManVol2/
The UNIX 7th edition manual came in three physical volumes: 1, 2A and 2B. This
archive is a(n almost) complete archive of the material in volumes 2A and 2B,
describing the various parts of the system in more detail. Volume 1 was a copy
of the online man pages. Coverage includes introductions and references for
many common UNIX utilities such as
wget -mpck -U "" -e robots=off -w 1 -X "*" -I "/44doc" https://docs.freebsd.org/44doc/
This is a snapshot of the 4.4BSD Lite documents. Many are useful for
programming under 2BSD on the PDP-11 or 4BSD on the VAX. Examples include
curses.h, system calls, vi, and networking. Also includes A
Guide to the Dungeons of Doom, the manual for
wget -mpck -U "" -e robots=off -w 1 ftp://moe.2bsd.com/2.11BSD/
Contains patch sets for 2.11BSD. Snapshot 2018-08-22 contains patch sets 001-450.
The Design and Implementation of the 4.4BSD Operating System
wget -mpck -U "" -e robots=off -w 1 -X "*" -I "/doc/6.0-RELEASE/usr/share/doc/en/books/design-44bsd/" https://docs.freebsd.org/doc/6.0-RELEASE/usr/share/doc/en/books/design-44bsd/
This is a wonderful overview of the 4.4BSD kernel. Useful for anyone intending to dive into 2.11BSD’s internals.