At 03:07 PM 4/9/2007, Peter St. John wrote:
Jim,
You are right, Xenix was available for the 286 in 85 (I bought my
286 in late 83 I think) but was available for the 8088 (the CPU on
the IBM PC, everyone says 8086 because of the sequence 80286,
80386...; I think the 80186 was a special purpose processor that
turned out to be more apt for pursuing a CPU line than the 8088 was) in 83.
The 80186 and 80188 were higher integration versions of the 8086 and
8088 with onchip peripherals (such as memory decodes, interrupt
controller, counter/timer, etc.) You can still buy 80188 based
single board computers for industrial control kinds of
applications. The 8086 had a heyday in the MultiBus era, but because
it's a 16 bit bus it made for expensive hardware (had to have two
8bit wide proms to boot from, and 16 bit wide ram, etc.).. the 8088
was designed to address this for low cost systems (e.g. the IBM PC),
especially because it could use all the 8080 and 8085 peripherals
(8259, 8255, 8250, 8253, etc.) for which there was extensive design,
programming, and layout expertise. I can't recall, off hand, whether
the 8088 had the same hooks that the 8086 had for multiprocessor
systems (more correctly, whether the iAPX/88 and iAPX/86 system
architectures...)
In a fascinating connection with clusters, the original Intel iPSC/1
Hypercube used ethernet as the interconnect among the processors, and
used 286 SBCs as the nodes. Each node had multiple Ethernet
interfaces, depending on the cube order (i.e. an order 3 cube had 4
interfaces for each node.. 3 to other nodes and 1 to the cube
manager). The iPSC/2 moved up to 386/387 nodes (and i960 or i860
nodes) and a more specialized interconnect. Both ran Xenix or Sys.V,
as I recall. The basic programming model was message passing between
processes, and the "cube manager" (what would be called a head node
in Beowulfery) would be used to fire up processes on nodes.
The iPSC/1 was in early 80s... I think the first hypercube was at
CalTech a few years earlier, and may have been an early instance of
the use of MPI. I had a "sugarcube" demo unit for a few months,
which was a 4 processor box, with the cube manager separate. Enough
to fool around with message passing and such.
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