"A tape-based piece of unique Unix history may have been lying quietly in storage at the University of Utah for 50+ years," reports The Register. And the software librarian at Silicon Valley's Computer History Museum, Al Kossow of Bitsavers, believes the tape "has a pretty good chance of being recoverable."Long-time Slashdot reader bobdevine says the tape will be analyzed at the Computer History Museum. More from The Register:The news was posted to Mastodon by Professor Robert Ricci of the University of Utah's Kahlert School of Computing [along with a picture. "While cleaning a storage room, our staff found this tape containing #UNIX v4 from Bell Labs, circa 1973..." Ricci posted on Mastodon. "We have arranged to deliver it to the Computer History Museum."] The nine-track tape reel bears a handwritten label reading: UNIX Original From Bell Labs V4 (See Manual for format)... If it's what it says on the label, this is a notable discovery because little of UNIX V4 remains. That's unfortunate as this specific version is especially interesting: it's the first version of UNIX in which the kernel and some of the core utilities were rewritten in the new C programming language. Until now, the only surviving parts known were the source code to a slightly older version of the kernel and a few man pages — plus the Programmer's Manual [PDF], from November 1973. The Unix Heritage Society hosts those surviving parts — and apparently some other items of interest, according to a comment posted on Mastodon. "While going through the tapes from Dennis Ritchie earlier this year, I found some UNIX V4 distribution documents," posted Mastodon user "Broken Pipe," linking to tuhs.org/Archive/Applications/Dennis_Tapes/Gao_Analysis/v4_dist/. There's a file called license ("The program and information transmitted herewith is and shall remain the property of Bell Lab%oratories...") and coldboot ("Mount good tape on drive 0..."), plus a six-page "Setup" document that ends with these words... We expect to have a UNIX seminar early in 1974. Good luck.Ken ThompsonDennis RitchieBell Telephone LabsMurray Hill, NJ 07974Read more of this story at Slashdot.