Re: networked processors and parallelism
At 08:55 AM 6/21/00 -0700, Jeff Fox wrote:
>Dear MISC readers:
>
>vic plichota wrote:
> >
> > > Sounds like Transputer. This has been tried and is out of fashion
> > now,
> > > since it appearantly couldnt live up its promises..
> >
> > Bullshit -- the only reason that Transputer or other networked
> > multi-processor system achitectures are "out of fashion" is because
> > MicroSoft somehow managed to saturate the market place with the
> > stupid ISA-PC, despite inferior technical merit.
>
>My take was that the Transputer was unusual in that it tried
>to provide inexpensive multi-processing but targeted to compete
>on the high end where people really don't care about expense.
>In that market it is power and compatibility (read Fortran) not
>power and low cost.
>
>Thes people ten to have government funding and the status
>of your project is proportional to what you spend. Also
>for these kind of grand challenge problems there are good
>reasons for wanting the biggest most powerful nodes you can
>get in your multiprocessor rather than more of them. The
>transputer just wasn't able to compete in the high end
>supercomputer arena where people want super power and really
>don't care about expense very much. The extra work of using
>cheap processors to do that sort of high end grand challenge
>just wasn't the best match to the intended target.
>
>I understand that there were other problems related to the
>marketing strategy and that government support sort of tended
>to make the project country specific and reduced wider
>acceptance of the thing. That was the take at the PPC on
>the Transputer. They also felt the focus on Occam hurt
>the people in that market just wanted parallel Fortran.
>
>F21 also was intended as an unusual multiprocessor intended
>to be inexpensive. But unlike Transputer it was not targeted
>for grand challenge crunching of titanic arrays of FP data.
>The focus of F21 is nearly opposite the transputer in most
>other ways. The focus was on integer, Forth, and I/O hardware.
>
>Also they are quite different as CPU go. In sense they have
>something in common. The transputer uses an on chip stack,
>but since it is only 3 cells deep it makes P21 look like
>a machine with a lot of registers. F21 has an instruction
>set that has a very close match to the language developed
>by its designer.
>
>About the fashion point. I agree. As I said it was never
>our intention to just make a fashionable chip like some
>other people.
>
>But the problem is bigger than that. Multi-processing
>never was in fashion except in the high end supercomputer
>niche. It has only begun to creep in to PCs in the last
>few years with 2 to 4 processors max instead of 1.
>The supercomputing crowd has also moved to multiprocessing
>on networks of PCs or workstations because it is a better
>buy than the old supercomputers they used to use.
>
>About the only people who understand multiprocessing think
>that the only thing it is good for is supercomputing FP
>number crunching.
I wrote my first multiprocessor program in 1987.
I used two Z-80s running FORTH.
One was a network processor the other controlled the machine.
It was the simplest way to get the processing speed I needed at the time.
Interprocessing communications was handled by a one level deep FIFO (an 8255).
It seemed so obvious at the time. It seems even more obvious now.
===========================================
Our religion is not FORTH. It's simplicity.
FORTH is just a local minimum.
'Simple' Simon
