52 years later, only known copy of Unix v4 recovered from randomly found tape, now up and running on a system — first OS version with kernel and core utilities written in C

https://www.tomshardware.com/software/linux/unix-v4-recovered-from-randomly-found-tape-at-university-of-utah-only-known-copy-of-first-os-version-with-kernel-and-core-utilities-written-in-c