Secure Unix ancestor KSOS did type safety before Rust made it cool

For the first time, the source code of KSOS, backed by the US Department of Defense in the late 1970s and 1980s, is available to the public in the archives of The Unix Heritage Society (TUHS). TUHS volunteers preserve the historical source code and documentation of the original UNIX – or as much of it as is left. A few days ago, in an email to its mailing list, TUHS founder Warren Toomey announced the addition of KSOS to the collection.