Re: tlug: Karl-Max has cool dreams [was: dual-pentium processors]

[Karl-Max Wagner <karlmax@example.com>]

> There are not many people who can write a program that
> scales to 64 processors, and if you can, it is an aweful lot

Depends on the problem. I don't think much in terms of
scientific (or mathematical) computing. Most run-of-the-mill
stuff is either heavyload graphics processing (moviemaking, game
rendering etc. ) or signal processing (digital filtering, sound
processing etc.). These things are inherently paralell in their
nature and scale well.

> of work.  And then there are more problems where we don't
> know any useful parallel algorithm than problems where such

Right. But they are in the minority.

> algorithms are know.  Furthermore, there is no compiler
> taking your sequential program to a parallel program[1].  I

Obviously. You have to think paralell from the outset. Think
like a hardware designer. They do that every day.

> I don't think, there will be ubiquitous parallel computing
> without a paradigm shift in programming languages.  Please

Let's say: you need the same paradigm like a hardware
description language.

> don't extrapolate from your two- or four-processor

I don't have any ! I am interested in that more from a DSP point
of view - and there it's quite commonplace.

> With 16 it already starts to get nasty and 64 processors are 
> a nightmare.

If you insist on converting sequential code into paralell one,
definitely. If you write code that consists of a lot of more or
less independent processes, it's not much of a problem - IMHO
the latter is easier to understand and to conceive of anyway -
who likes large monolithic programs ?

Again: if you come from a hardware and logic design background,
like things like FPGA's than you are in a good position for
paralell programming. If your background is writing sequential
code ONLY, it's a nightmare.

Actually, I did lots of stuff in the past using "TTL-graves" -
typical old style logic design which is inherently paralell.
When I started using micros, I kinda hated the sequential
thinking required there - I had to sequentialize problems that
were inherently paralell. This is why I like things like
multitasking, paralell processing etc.: this way I can go back
to the design methology used in hardware design. It's a dream
come true !

To put it in a nutshell: With paralell computing you gotta think
paralell. Kiss your old sequential habits goodbye !

                               Karl-Max Wagner
                               karlmax@example.com
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