--- Bill Pechter <pechter_at_bg-tc-ppp1660.monmouth.com> wrote:
I wrote:
> > ...most customers did not require dual processors and SMP didn't emerge
> > until 1988 with VMS 5.0, long after the 11/780 was being sold as new.
> >
> >
> > -ethan
>
> The 11/785's were not SMP... they were (IIRC) a fast schottky
> rework of the 11/780's ttl which was about 1.5 times an 11/780.
Does SMP have a meaning in this context besides Symmetric Multi-Processing?
What I meant by my comment was that with VMS versions prior to 5.0, if you
had multiple processors, one was "master" and could go into kernel mode,
the other were slaves and never went into kernel mode. I had to update
our COMBOARD drivers in 1988 to handle the extra level of spin-locking
required of all privileged code to accomodate the fact that more than one
CPU might be attempting to access systems structures at the same time.
This has nothing to do with the logic family used to implement a processor.
> The 11/782 was dual cpu 11/780's with shared memory bus run
> master-slave for compute bound tasks with the i/o run off of one
> cpu.
Right. Developed by George Goble (of the LOX-on-the-BBQ fame), et. al, at
Purdue, IIRC.
> The 11/787 was similar with dual 11/785's on the multiport memory.
Never saw one of those.
> I was told the 11/785 was done in DEC Europe as a mid life kicker for
> the 11/780 when the Venus 11/790 -- er 11/860 -- er 8600 was VERY LATE
> getting built.
>
> Bill
My understanding was that the 11/785 was DEC's official implementation
of what George and crew cobbled together as the 11/782. It only saw
the light of day because, as you say, there was a gap in DEC's product
line with the delays in the 8600 and customers wanted more than what was
presently out there.
Disclaimer: when this stuff was current, we had a couple of 11/750s and
an 11/730 at work. I never got to dig in the guts of an 11/780, so only
parts of this is from personal experience.
-ethan
=====
Visit "The Seventh Continent"
http://penguincentral.com/penguincentral.html
__________________________________________________
Do You Yahoo!?
Make international calls for as low as $.04/minute with Yahoo! Messenger
http://phonecard.yahoo.com/
Received on Thu Jul 26 2001 - 09:02:22 BST