heck, are 11/785s extinct? - test-drb@ccmp.vtda.org

26 Jul 2001

...
  Date: Thu, 26 Jul 2001 07:02:22 -0700 (PDT)
 From: Ethan Dicks &lt;ethan_dicks(a)yahoo.com&gt;
  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 782 was the DEC solution, using a multiported memory (MA780).
Each CPU had it's own SBI, with private UBA's and MBA's (UNIBUS and
MASSBUSS adapters);
<a
href="http://www.montagar.com/dfwcug/VMS_HTML/timeline/1982-5.HTM"…
V3</a>
   VMS V3 supported three new processors: the VAX-11/750,
   VAX-11/725, VAX-11/782. V3 features included asymmetric multiprocessing
   (ASMP) for VAX-11/782, support for new architectures, protocols and
   busses, system communication architecture (SCS), mass storage control
   protocol (MSCP), lock management system services, and MONITOR utility
   for performance monitoring.
<a
href="http://www.netbsd.org/Documentation/Hardware/Machines/DEC/vax/va…
hardware reference - VAX 700 series</a>;
   VAX 11/782
   Nickname: Atlas Cpu: Dual KA780
   Vup: 1.8
   Bus: 2 SBIs with 15 nexus slots each. Each slot can take a UBA (UNIBUS
   adapter), MBA (MASSBUS Adapter), or CI. (?)
   Introduced: 1982 NetBSD: (?) Probably
The Purdue work connected the two CPU's by replacing the SBI bus
terminator with the second CPU.  There aparently were also a few
11/784s, with 4 CPU's, also using the MA780.
http://www.cam.anglia.ac.uk/~systimk/History/Vaxes.Txt, discusses it all,
an includes a 1993 message from George.
...
  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. 
The 785 was a late life kicker to the 780;
It was not (by itself) a multiprocessor system.
<a
href="http://www.montagar.com/dfwcug/VMS_HTML/timeline/1984-2.htm"…
   CPU cycle time in the VAX-11/785 was 133ns, 50% faster
   than the 200ns cycle time of the VAX-11/780. The accelerated cycle time
   allowed all CPU operations to run up to 50% faster, resulting in higher
   throughput, faster response time and the ability to support more users
The NetBSD VAX hardware reference says that a 782 built from two 785's
would have been called a "787"
Disclaimer;
        I worked at DEC in the 80's, but on 36-bit products.
        (and briefly on the 64-bit RISC machine, codenamed "SAFE",
        which, after Cutler grabbed the project, was renamed PRISM).