README file to accompany the KSOS distribution

KSOS was the U.S. Department of Defense (DoD) Kernelized Secure Operating
System (KSOS, formerly called Secure UNIX). KSOS is intended to provide
a provably secure operating system for larger minicomputers. "KSOS -
The design of a secure operating system"
[https://ieeexplore.ieee.org/document/8817190 -- requires subscription]

More information here: https://grokipedia.com/page/ksos

KSOS came in two flavours: KSOS11 for the PDP-11 and KSOS32 for the VAX.

See also https://seclab.cs.ucdavis.edu/projects/history/seminal.html
(search for KSOS).

Tom Perrine gave a talk at DEF CON 20 on the creation of KSOS:
https://www.youtube.com/watch?v=fjJjppHPcdA

Finally, Tom Perrine wrote a retrospective on KSOS:
https://www.usenix.org/publications/login/december-2002-volume-27-number-6/kernelized-secure-operating-system-ksos

Tom Perrine summarised KSOS:
https://www.tuhs.org/pipermail/tuhs/2025-October/032635.html

Asked about the source tree of KSOS, Tom Perrine replied that he had a copy
of the final tree: https://www.tuhs.org/pipermail/tuhs/2025-October/032674.html

Asked which compiler was used, Jon Forrest answered:
https://www.tuhs.org/pipermail/tuhs/2025-October/032675.html

Tom Perrine was able to recover the source tree (personal communication;
Perrine-to-Stuff-2026-03-12.txt). He attributed the actual provenience to
Jeff Makey.

The source trees are "raw" development trees with temporary files and so on.

I contact Warren Toomey about inclusion in the TUHS source repository.
He replied: "The compressed tarball would be excellent along with a
text README file with some details of KSOS and the provenance of the
tarball." (personal communication; Toomey-to-Stuff-2026-04-27.txt)

Hopefully, this suffices.

john o goyo
(stuff@riddermarkfarm.ca)