[TUHS] UNIX v4 Source Code Commentary - complete book now available

[Thalia Archibald via TUHS]

On Jan 12, 2026, at 16:20, Phil Budne wrote:
> General question: Is "v4" really the right thing to call the tape?


The manual editions are a messy way to refer to UNIX snapshots.
UNIX was versioned by the manual releases, but the system was distributed as a
copy of the current system on the Research machine, whenever the tape was cut.
Different licensees received different snapshots, but the same manual.

Since we only have a few snapshots now, it’s tempting to call them by the manual
in use at the time, but it’s rather inaccurate. It’s much better to call them by
some unique identifier; Utah V4 in this case or Dennis_v5, Henry_Spencer_v7,
Nijmegen_v7, etc., as in the TUHS Archive. Or alternatively, to call it a UNIX
V4 snapshot from 12 June 1974.

As you say, the V5 manual is dated June 1974. The files on the Utah V4 tape are
dated 12 June 1974 and documented to have been sent after May 1974, but with a
V4 manual. So we’re looking at near-V5 code just days or weeks before the V5
manual was released. However, I continue to call it “V4”, as that is evidently
what this particular tape was thought of as, since that was the manual version
that accompanied it.

Thalia