Is 2.11BSD < 4BSD? It depends. (was: [PATCH v1 2/4] sys/man2/sysctl.2: HISTORY: wfix)

["G. Branden Robinson" <g.branden.robinson@gmail.com>]

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At 2025-12-29T22:59:11-0800, Collin Funk wrote:
> It actually existed before 4.4BSD. It existed in 2.11BSD at least [1].

Hang on a second.  BSD version numbers are a little funny.

It is true that 1BSD < 2BSD < 3BSD < 4BSD.

After that, things get a little weird.

2BSD targeted only the PDP-11, and swapped out entire processes just as
Unix historically always had.

3BSD targeted the VAX, and supported demand paging--just as UNIX 32/V,
the most recent common ancestor of AT&T System III/V and [34]BSD,
did.[0]

4BSD was a relatively minor update to 3BSD, also exclusively for the
VAX.  4.1BSD was a much bigger deal and would have been 5BSD, except
AT&T blew a gasket over the version numbered, seeking a proprietary
claim over the number five.  This has been discussed just this week on
the TUHS list.[1]

2BSD however was not abandoned as soon as 3BSD or even 4BSD showed up.
Some people still had PDP-11s around.  And thanks to (Open)SIMH, we can
all still run one if we choose.

Features from 3,4BSD got backported to 2BSD, which eventually stabilized
its minor version number at "11", I suspect because that was
irresibility useful to characterize the system's only supported target
architecture.

2.11BSD continues to be maintained today, as a set of literally hundreds
of patches, as Berekeley-flavored Unix aficionadios explore just what
they can do with what is now basically an "embedded system".

The most recent patch I know of is #498, dated 2 September.[2]

I wish we had a modern package manager for the thing.  I've never been
crazy about BSD's "patch && make world" approach.  :-P

Regards,
Branden

[0] The demand-paged kernel was such a big deal that it's why the
    "virtual memory" version of the Unix kernel appeared on disk as
    "vmunix".  The Linux kernel aped this as "vmlinux"--"vmlinuz" for
    its compressed form--even though there has never existed a
    traditionally swapping version.  The more arbitrary and esoteric a
    naming convention is, the more tightly Unix people cling to it.

[1] https://www.tuhs.org/pipermail/tuhs/2025-December/032903.html
[2] https://www.tuhs.org/Archive/Distributions/UCB/2.11BSD/Patches/

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