Emilio Cobos Álvarez
bitsavers.orgThe Unix V4 tape read was successful
https://discuss.systems/@ricci/115747843169814700
aap has it booting
it appears to be something between the documentation for V4 and V5
https://squoze.net/UNIX/v4/
--- quote from Matt Day email:
Correction: the commands present in Angelo's copy of the v4 tape include:
dd, diff, glob, lpr, msh, pwd, tee
Not present in Angelo's copy of the v4 tape: col, eqn, neqn, spell
Present in Fifth Edition: all of the above, according to
https://dspinellis.github.io/unix-history-man/man1.html
On Fri, Dec 19, 2025 at 9:28 PM Matt Day <[email protected]> wrote:
> Cool, thanks Angelo.. I got it running easily thanks to your efforts.
>
> At a glance it looks like Fifth Edition to me... all the files are
> timestamped June 10 - 12, 1974. Commands present include col, dd, diff,
> eqn, glob, lpr, msh, neqn, pwd, spell, and tee -- according to
> https://dspinellis.github.io/unix-history-man/man1.html those commands
> first appeared in Fifth Edition and were not present in Fourth.
We received the tape in June 1974, due to delay in printing more documentation.
The documentation we received must have been for V4, since the label says to
“see manual for format”, written later by Jay Lepreau, the OS researcher in
whose documents it was found. Furthermore, the blue embossed label on the side
says UNIX V4 DIST, which I presume was put there by Bell Labs.
https://archive.org/details/thompson_to_newell_1974-05-31
UNIX wasn’t versioned as we know it today. 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. The manuals were versioned and you
got whatever the last one was.
The V5 manual is dated June 1974 (anyone know a better date?), same as our tape.
I suspect the next manual was finished days or weeks after this was sent, so
this may perhaps be the most extreme drift in an extant copy of UNIX between the
manual features and the shipped features.
The Dennis_v5 distribution on TUHS is dated 21 March 1975, just two months away
from the May 1975 release of the V6 manual. (Which explains why I found it so
close to V6 when I studied it.) The Utah “V4” is a much cleaner V5 than the V5
we have. I’ve had been saying It’s probably V5 minus a tiny bit, which turned
out to be quite true.
Thalia
Letter to Martin Newell on UNIX delivery to University of Utah : Ken Thompson : Free Download, Borrow, and Streaming : Internet Archive
A letter from Ken Thompson to Martin E. Newell apologizing for delay in the delivery of UNIX to the University of Utah, due to running out of copies of...
dgelessus@bitsavers mailing list archive link, for reference: https://www.tuhs.org/pipermail/tuhs/2025-December/032861.html
Rue Mohr@bitsavers ugh, tee has been around forever and I still am not familiar with using it.
R.L. Dane 
🍵 
Useful for saving the output of a command while viewing it at the same time, like
sudo apt-get dist-upgrade 2>&1 | tee ~/big-fat-upgrade-log.txt
@bitsavers The server at squoze.net only supports HTTP and not HTTPS - here's a working link: http://squoze.net/UNIX/v4/
and for those who want to read along, the mailing list archive links:
https://www.tuhs.org/pipermail/tuhs/2025-December/032855.html
https://www.tuhs.org/pipermail/tuhs/2025-December/032860.html
Thanks for this!!
A .tap image with the two bad blocks fixed.
I'm going to push this to bitsavers.
Video of the disk image running on a real PDP-11/45
https://www.youtube.com/watch?v=zh-9rBYmGow
https://www.youtube.com/watch?v=zh-9rBYmGow
UNIX V4-1/2 on 1972 PDP-11/45 First Boot
RealGene ☣️@bitsavers
C'mon, play Hunt the Wumpus.
C'mon, play Hunt the Wumpus.
Michael Engel
The Orange Theme@bitsavers Oh, this is phenomenal news! 🥰 Amazing work!