Sequent talk at LBL (7/31)

[jsq at im4u.UUCP]

We have one (12CPUs, 16Mbytes memory, 1 Eagle, 1 SCSI Eaglet, 1 SCSI
cartridge tape drive, 1 Cipher 1/2" tape drive).  We like it.

Our experience bears out the linearity of increase in throughput with
increasing numbers of CPUs, for fixed point CPU bound processes.  For
floating point, the throughput is even somewhat better (the individual
floating point units may not scream, but there's one per processor).
Installation took less than two hours, even after confusion over who
was to supply the Ethernet transceiver and cable (us).  Reliability has
been phenomenal:  the worst problem has been an overheating tape drive,
fixed by turning the drive off when not in use.  The OS is 4.2BSD,
right down to the bugs (the tset bug, the rcp bug, the rwhod bug...),
though naturally there are proprietary mods to the kernel to support
the multiprocessing (including shared memory and semaphores).

Minuses:  Disk I/O through the Multibus is a bottleneck, though not
enough to be a big problem.  The C compiler is slow.  The Pascal compiler
is buggy and will not compile some things which will compile on most other
known pascal compilers.  It also won't compile TeX.  (-: It's fast, though. :-)
System sources are difficult to come by, though most VAX 4.2BSD user program
sources will compile and run.

The company is very responsive.  Both disk I/O and the C compiler are
quite noticably faster than when we got the machine in April, due to
a software update.  The bugs diminish.

There are several papers in the Portland USENIX Proceedings about the
machine, and also in IEEE Computer, etc.

Though other companies are working on multiprocessor systems of the
same general type as the Balance 8000 (i.e., multiprocessors with
memory shared among all processors, not dual processors or networked
single processors), Sequent appears to be the only one with an actual
product so far.

--->>> DISCLAIMER <<<--- This article is my personal opinion, and
does not necessarily represent that of my employers, or the University
of Texas, or Sequent Computer Corporation, or Opus the Penguin,
not to mention reality.

PS:  Is anybody interested in an INFO-SEQUENT mailing list?
(If so, reply by *MAIL* to me.)
-- 
John Quarterman,   UUCP:  {ihnp4,seismo,harvard,gatech}!ut-sally!jsq
ARPA Internet and CSNET:  jsq at ut-sally.ARPA, soon to be jsq at sally.UTEXAS.EDU