Bell Labs 'Unix' Tape from 1974 Successfully Dumped to a Tarball

Archive.org now has a page with 'the raw analog waveform and the reconstructed digital tape image (analog.tap), read at the Computer History Museum's Shustek Research Archives on 19 December 2025 by Al Kossow using a modified tape reader and analyzed with Len Shustek's readtape tool.' A Berlin-based retrocomputing enthusiast has created a page with the contents of the tape ready for bootstrapping, 'including a tar file of the filesystem,' and instructions on dumping an RK05 disk image from tape to disk (and what to do next).

Research professor Rob Ricci at the University of Utah's school of computing posted pictures and video of the tape-reading process, along with several updates. ('So far some of our folks think they have found Hunt The Wumpus and the C code for a Snobol interpreter.')
University researcher Mike Hibler noted the code predates the famous comment 'You are not expected to understand this' — and found part of the C compiler with a copyright of 1972.

The version of Unix recovered seems to have some (but not all) of the commands that later appeared in Unix v5, according to discussion on social media. 'UNIX wasn't versioned as we know it today,' explains University of Utah PhD student Thalia Archibald, who researched early Unix history (including the tape) and also worked on its upload. 'In the early days, when you wanted to cut a tape, you'd ask Ken if it was a good day — whether the system was relatively bug-free — and copy off the research machine... I've been saying It's probably V5 minus a tiny bit, which turned out to be quite true.'

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