Given the tendency of websites to disappear over time, I archive sites that I find particularly helpful.

Ralf Ohmberger’s Homepage

URL: https://www.amplifier.cd

Command: wget -mpck -U "" -e robots=off -w 1 https://www.amplifier.cd


Ralf Ohmberger’s homepage has a wealth of high-quality, original photos of test equipment including detailed descriptions of repairs. He also publishes application notes, machining tips and other interesting tidbits.


URL: http://ioccc.org

Command: wget -mpck -U "" -e robots=off -w 1 http://ioccc.org


The International Obfuscated C Code Contest (IOCCC). In their own words:

Frain Research

URL: http://web.frainresearch.org:8080

Command: 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

URL: http://simh.trailing-edge.com

Command: 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

URL: https://wolfram.schneider.org/bsd/7thEdManVol2/

Command: 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 sh, sed, make, awk, etc.

4.4BSD Documents

URL: https://docs.freebsd.org/44doc/

Command: 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 documentation for curses.h, system calls, vi, and networking. Also includes A Guide to the Dungeons of Doom, the manual for rogue.

2BSD Patches

URL: ftp://moe.2bsd.com/2.11BSD/

Command: 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

URL: https://docs.freebsd.org/doc/6.0-RELEASE/usr/share/doc/en/books/design-44bsd/index.html

Command: 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.