On 6/20/2026, ben <bfranchuk(a)jetnet.ab.ca> wrote:
PL/1 and C are the only two high level languages a
operating system is
written in, that I can think of that are well documented, and easily
found on the WEB.
Additional examples:
Pilot (the embedded operating system for the Xerox Star office
automation system) was written in Xerox's proprietary Mesa language.
History and documentation of Mesa (and some Pilot documentation and
early source code) are available here:
https://softwarepreservation.computerhistory.org/mesa/
Taos, the operating system for the DEC Systems Research Center Firefly
multiprocessor workstation, was written in Modula-2+, which added
threads, garbage collection, and runtime type dispatch to Modula-2.
History and documentation of Modula-2+ (and Taos) are available here:
https://softwarepreservation.computerhistory.org/modula2+/
SPIN, an extensible operating system written at the University of
Washington, was written in Modula-3 (with small extensions). History and
documentation for Modula-3 are available here:
https://softwarepreservation.computerhistory.org/modula3/ and
information on SPIN is available here:
https://softwarepreservation.computerhistory.org/modula3/#SPIN_M3 .