UNIX History

[Guy Harris]

Correcting a few typos: "Heiz Lacklama" is actually Heinz Lycklama, now
of Interactive Systems; "UNIX/PWD" is actually PWB/UNIX.

MERT was actually a separate OS from UNIX, which had a UNIX overlay on
top of it (so the first case of putting a UNIX-compatible interface on
top of a different OS was Bell's own MERT!).

	In this time period, new PDP processors such as the PDP 11/34,
	and PDP 11/23 and even a PDP 11/55 were released and offsprings
	to UNIX developed for them.

The 11/55 was just an 11/45 with faster memory and a faster floating point
unit, so the standard UNIX that ran on an 11/45 would run on the 11/55.
The 11/34 and 11/23 would, by and large, run versions of UNIX that ran on
the 11/40, except that they could support the floating point instructions.
(They also had other features, like the 11/34's cache and the 11/23+'s
22-bit UNIBUS, but standard UNIX know about them.)

	UNIX/TS was USG UNIX and PWD UNIX combined.

And was derived from a version of UNIX that was mostly Research V7, although
it was, I believe, slightly earlier than the released V7 (it had a V6-ish)
terminal driver, for instance) - the original USG UNIX and PWB/UNIX were
derived from V6 or from V6es later than the released V6 - a set of "50 changes"
that would turn V6 into what was running at Research at the time when the
changes were sent out was done by Ken Thompson, and there was a
"Phototypesetter, Version 7" distribution that contained the "modern"
nroff/troff/eqn/tbl, the "modern" C compiler with "long", "typedef", etc.,
the "modern" linker and archiver, and the Standard I/O library.  Most of the
"50 changes" and "Phototypesetter, Version 7" stuff was in PWB/UNIX 1.0.

	Another version of MERT formed the basis for DMERT, a Duplex operating
	system.

For the 3B20-D; the D stood for Duplex and meant there were two CPUs in a
redundant configuration.

	In 1979 UNIX/RT was announced as 1 year to freeze, with UNIX/RT
	VAX officially dead.

Just out of curiosity, why was UNIX/RT canned if, as stated earlier, it was
felt that UNIX/RT could do everything UNIX/TS could and more?

	The remaining UNIX/TS VAX was again modified by the Indian Hill
	computer center into another product called UNIX/TS Augmented.

Was there also *another* UNIX/TS variant called UNIX/TS+ (plus)?

	Finally, the product internal to AT&T Bell Labs call UNIX/TS
	was the only major product supported.

And was named just UNIX as of release 3.0 (release 3.0.1 was publicly
released as System III); it incorporated stuff from TS Augmented and
TS+.

Was CB-UNIX based on UNIX or MERT, and how much stuff going into the
mainstream UNIX (S3, S5) came from CB-UNIX?

	Guy Harris
	{seismo,ihnp4,allegra}!rlgvax!guy