News: 0180014358

  ARM Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life (Terry Pratchett, Jingo)

Lost Unix v4 Possibly Recovered on a Forgotten Bell Labs Tape From 1973 (theregister.com)

(Sunday November 09, 2025 @04:43PM (EditorDavid) from the kernels-of-hope dept.)


"A tape-based piece of unique Unix history may have been lying quietly in storage at the University of Utah for 50+ years," [1]reports The Register . And the software librarian at Silicon Valley's Computer History Museum, Al Kossow of Bitsavers, [2]believes the tape "has a pretty good chance of being recoverable." Long-time Slashdot reader [3]bobdevine says the tape will be analyzed at the Computer History Museum. More from The Register:

> The news was [4]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 [5]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 [6]source code to a slightly older version of the kernel and a few [7]man pages — plus the [8]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 [9]tuhs.org/Archive/Applications/Dennis_Tapes/Gao_Analysis/v4_dist/ .

There's a [10]file called license ("The program and information transmitted herewith is and shall remain the property of Bell Lab%oratories...") and [11]coldboot ("Mount good tape on drive 0..."), plus a [12]six-page "Setup" document that ends with these words...

We expect to have a UNIX seminar early in 1974.

Good luck.

Ken Thompson

Dennis Ritchie

Bell Telephone Labs

Murray Hill, NJ 07974



[1] https://www.theregister.com/2025/11/07/unix_fourth_edition_tape_rediscovered/

[2] https://www.tuhs.org/pipermail/tuhs/2025-November/032765.html

[3] https://slashdot.org/~bobdevine

[4] https://discuss.systems/@ricci/115504720054699983

[5] https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4

[6] https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys

[7] https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man

[8] https://dspinellis.github.io/unix-v4man/v4man.pdf

[9] https://www.tuhs.org/Archive/Applications/Dennis_Tapes/Gao_Analysis/v4_dist/

[10] https://www.tuhs.org/Archive/Applications/Dennis_Tapes/Gao_Analysis/v4_dist/license

[11] https://www.tuhs.org/Archive/Applications/Dennis_Tapes/Gao_Analysis/v4_dist/coldboot.pdf

[12] https://www.tuhs.org/Archive/Applications/Dennis_Tapes/Gao_Analysis/v4_dist/setup.pdf



A lucky find. (Score:4, Interesting)

by fuzzyfuzzyfungus ( 1223518 )

It's not going to get any easier to find definitely bot slop free software as time goes on; but we can be fairly sure about this stuff. Like hunting for low background steel.

Re:"will be analyzed at the Computer History Museu (Score:5, Informative)

by kiore ( 734594 )

Caldera open sourced early versions (32-bit 32V UNIX; 16 bit UNIX Versions 1, 2, 3, 4, 5, 6, 7) of Research UNIX in 2002. [1]https://www.tuhs.org/Archive/C... [tuhs.org]

[1] https://www.tuhs.org/Archive/Caldera-license.pdf

Re: (Score:1)

by ziggyzaggy ( 552814 )

Must have been Darl McBride posing as AC you answered 8D

So what was it written in before C? (Score:2)

by smithmc ( 451373 )

B? Or BCPL?

Re:So what was it written in before C? (Score:5, Informative)

by ebcdic ( 39948 )

The kernel was written in PDP-11 assembler.

Re: (Score:2)

by _Shorty-dammit ( 555739 )

*assembly

Geniza from between First and Second Temple? (Score:2)

by BigBlockMopar ( 191202 )

So this is Geniza from between the First and Second Temple? Sorry, just had to ask. :)

Remains to be seen... (Score:2)

by DrXym ( 126579 )

... if running tar will extract it

Re: (Score:2)

by bjoast ( 1310293 )

... or if they have to pay for WinRAR.

Re:Remains to be seen... (Score:4, Interesting)

by Marxist Hacker 42 ( 638312 ) *

Or if it's even still readable. Intel when retrieving the 486 tape-in for the Edison project had to bake the tapes in an oven to remove moisture, and then had ONE CHANCE at imaging the tape as it crumbled to dust going through the reader.

Re: (Score:3)

by HighOrbit ( 631451 )

Which makes me fear for civilization. Think of all the knowledge that will be lost when the 'digital' media (tapes, CDs, magnetic HDDs) is either degraded or the tech is so old we can no longer access it with current formats or machines. I know there is some 'archival' quality CDs, but they are few and far between. Few digital records are on 'archive' quality media.

Re: (Score:2)

by _Shorty-dammit ( 555739 )

Everybody knows you can archive things forever just by packing it up, encrypting it, and putting it in a "Britney Spears sex tape" torrent...

Re: (Score:2)

by AmazingRuss ( 555076 )

That's been happening for at least 10,000 years. We deal with it ok.

Re: (Score:2)

by bill_mcgonigle ( 4333 ) *

I have a floppy controller on order that doesn't know how to read disks; it just passes through magnetic field data to software which is supposed to be able to reconstruct the disk image.

Hopefully these tapes will be OK to read as long as somebody can build a magnetic read head of the correct type.

Maybe with ML there will be a reasonable chance of reconstructing faded regions. Old audio tape is still mostly fine, so fingers crossed.

BTW, what a great job these folks have!

Re: (Score:2)

by CommunityMember ( 6662188 )

> Or if it's even still readable.

The Computer History Museum has had previous success reading such 9-track tapes (they have a dedicated lab for restoration and recovery).

Re: (Score:2)

by ArchieBunker ( 132337 )

It's not so much the tape turning to dust but the glue holding the oxide layer on breaking down. Some brands hold up better than others over time and storage conditions are a huge factor. Sitting in a climate controlled university building for decades is probably the best case scenario.

Okay, but the big mystery NOW is... (Score:3)

by 93 Escort Wagon ( 326346 )

Did they hold the 1974 seminar, or not???

Re: (Score:1)

by scalptalc ( 6477834 )

> Indeed, and it was The Beginning:

>> The first meeting of Unix users took place in New York in 1974, attracting a few dozen people; this would later grow into the USENIX organization.

> [1]https://en.wikipedia.org/wiki/History_of_Unix#1970s>https://en.wikipedia.org/wiki/History_of_Unix#1970s [wikipedia.org]

I'd buy vintage merch from that if there was some, even a ratty t-shirt that smelled of stale sweat and Old Spice.

[1] https://en.wikipedia.org/wiki/History_of_Unix#1970s

Meh? (Score:1)

by XaXXon ( 202882 )

The information ABOUT the version is much more valuable than the source code.

You don't put the source in a history book and that's the only place unix v4 is valuable.

Re: (Score:2)

by ArchieBunker ( 132337 )

Speak for yourself. Some of us own hardware that can run this.

Re: (Score:1)

by ziggyzaggy ( 552814 )

No, there are those of us who go into the historic Unix source code for technical interest, we even compile and run the old Unix versions on SIMH and such. You'lll find for example that the really well written man pages reference the stuff including additions and changes to argument behavior

Re:Meh? (Score:4, Insightful)

by drinkypoo ( 153816 )

> The information ABOUT the version is much more valuable than the source code.

The source code is the most important documentation about the source code.

Article is premature (Score:1)

by zforgetaboutit ( 9698824 )

As expected.

The only real game in the world, I think, is baseball...
You've got to start way down, at the bottom, when you're six or seven years
old. You can't wait until you're fifteen or sixteen. You've got to let it
grow up with you, and if you're successful and you try hard enough, you're
bound to come out on top, just like these boys have come to the top now.
-- Babe Ruth, in his 1948 farewell speech at Yankee Stadium