[TUHS] re: ATT 3b2

[dmr at plan9.bell-labs.com]

 > I'm interested in acquring an AT&T 3b2 computer.  One of these systems
 > used to run a famous public UNIX system "killer".  They also run #5ess
 > telephone switches, however the OS is different in that case
 > (DMERT/UNIX-RTR instead of whatever the consumer-level 3b2 runs).

 > If anyone has information on where to acquire these (I saw the recent
 > discussion on 3b1s and I know they are more prolific than 3b2s-- infact
 > a friend of mine used to have a UNIX PC which we set up a BBS on).

The 3B2 was not the same machine as the one in 5ESS, which
was/is the 3B20D, a fairly large duplexed machine (two processors
that mutually checked each other).  The 3B2 was a desktop.
The 3B20D wasn't sold commercially, as far as I know.  There
was a 3B20S (multi-cabinet) that at least nominally
was commercially available.

Their ISAs were not quite the same, but some assembler language
tricks made the assembler-level languages look quite similar.

	Dennis