Unix V4 tape found at The University of Utah

Man Pages (Part 1)

Software substrates: should there be only one?

A Lost Tape of Unix Fourth Edition Has Been Rediscovered After 50+ Years

52-year-old data tape could contain only known copy of UNIX V4

Ironclad – formally verified, real-time capable, Unix-like OS kernel

Sit – Create StuffIt archives on Unix systems

A Repository with 44 Years of Unix Evolution

Details about the shebang/hash-bang mechanism on various Unix flavours (2001)

Ask HN: If Unix gets more popular would you use it instead of Linux?