🚀 go-pugleaf

	I've worked on two different commercially unsucessful
heterogeneous processor machines.  I don't think that I am the common
thread of failure ;-)
	The first was the Cydrome Cydra 5, which had a 50/25 MFLOP ECL
super computer wedded to a symetric 6 68020 cpu system running our
MP'ized  System V R3.2.  This machine was introduced in 1987.

	The second was the Stardent Stiletto, which had two MIPS
R3000, and four intel 860 processors.  Each R3000 had a tightly
coupled i860 which was connected as a vector processor, via our
implementation of the canonical Mips write buffer chip.  This is the
same model we used to build the Ardent Titan super graphics
workstations, altough we implemented the vector unit with gatearrays
and floating point cores.

	The other two i860s were on a separate graphics board, with
associated pixel processing power.

	One common problem with both machines is that the benchmark
results did not justify the cost of the machine.  This isn't a problem
with the design of the machine, per se: Instead, it is just hard to
write a benchmark that could effectively use all the power avialable
on a heterogeneous machine:

	SPEC ran on Stiletto just as well as it would run on any
machine with two 33MHz R3000/R3010 cpus.  SPEC didn't "notice" that
3D graphics could go on concurrently with no performance loss.
[Mashey: add a gSPEC to the mix: you must rotate a teapot while
gcc'ing ;-]

	Another common problem with both machines is twice the
technology risk exposure.  At Cydrome, the ECL super computer was
ready, and demonstrated at a trade show, one year before the general
purposed 68020 system was ready. At Ardent/Stardent, the dual R3000
system was ready 10 months before all the bugs were ironed out of the
i860 chips and our software.

	So, yes, Virginia, SHATOT (twice), and did not succeed.

> Based on previous experience in this group, Somebody Has Already Thought
> Of This.   If it's true that SHATOT, then please share it with us.

	Of course that by no means indicates that it is not a viable
proposition.  However, there are bones littered on the side of the
trail...


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