Overview
Released in 1992, this end-point of historical UNIX development on PDP-11's uses almost all features (22 bit addressing, separate I/D space, 3 processor modes) to squeeze a full UNIX with most of the 4.3 BSD features into a 16 bit machine. This operating system can be freely used under the Caldera license and is, therefore, the prime operating system for the w11 project.
2.11BSD Patches
When bringing up 2.11BSD in the w11a CPU two loose ends in the kernel showed up and were fixed with a patch
- the floating-point emulator FPSIM didn't work. Fixed with patch #445.
- boot from a RK05 wasn't possible. Fixed, together with several other little issues, with patch #446+447.
2.11BSD Patch Archive Mirror
The master archive of all published 2.11BSD patches is maintained by Steven Schultz on
ftp://ftp.2bsd.com/2.11BSD/
Access is unfortunately blocked for some ISP's, but it is mirrored at
https://www.tuhs.org/Archive/Distributions/UCB/2.11BSD/Patches/ ftp://ftp.dfupdate.se/pub/pdp11/2.11BSD/Patches/
A mirror, which allows direct access to each individual patch, is provided as part of this project under
https://www.retro11.de/data/211bsd/patches/
2.11BSD Source Code Viewer
The work on the patches mentioned above required a lot of detailed studies of the 2.11BSD source code, so it was natural to look for a fully htmlized and cross-references source code view. Since none of the available tools covered the requirements a new tool was written. For more info see
- project Old Unix XRef home page
- ouxr view of the 2.11 BSD code base
- a nice guided tour
2.11BSD System Images
A number of ready-to-use 2.11BSD system images are provided for usage on w11a or on SimH in a configuration equivalent to a w11a. Details are provided in the w11 project, section OS Kits.