Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!decwrl!labrea!glacier!jbn
From: jbn@glacier.STANFORD.EDU (John B. Nagle)
Newsgroups: comp.sys.next
Subject: Re: transputers
Message-ID: <17902@glacier.STANFORD.EDU>
Date: 15 Dec 88 01:41:14 GMT
References: <8304@pasteur.Berkeley.EDU>
Reply-To: jbn@glacier.UUCP (John B. Nagle)
Followup-To: comp.sys.transputer
Organization: Stanford University
Lines: 34

In article <8304@pasteur.Berkeley.EDU> e122-cl@polonius.berkeley.edu (Timothy Kong) writes:
>Simple question:  What are transputers?  
>Someone mentioned them in a few articles back but never explained what exactly
>they are.  I have heard talks about transputers' incredible processing power
>and how adding one of them would drastically speed up your machine.  
>Could somebody please elaborate.

       The INMOS Transputer is a microprocessor from INMOS, an English
computer firm, designed especially for use as a component of parallel
computers.  One 32-bit transputer is roughly comparable to a M68020 (+- 50%).
But they are intended for use in large arrays, perhaps as many as 1024
processors.  The machines have special hardware to support inter-CPU
communication in such arrays.  Adding one of them is not particularly
useful, but adding many of them makes a supercomputer of sorts.  

       Add-on transputer boards (typically with 4 transputers to a board)
are available for the PC/AT and Mac II.  Larger arrays are available for
workstation-class machines.  INMOS offers an interesting language called
OCCAM for programming transputer arrays, but a modified C seems to be
replacing OCCAM.  In either case, one must deal with concurrency explictly.
The model is a non-shared memory MIMD machine, with relatively large
memory, typically 64KB to 1MB, per processor.  

       The transputer has been out for a few years now, and has a reputation
of being a solution looking for a problem.  If you have a problem that
slices up well into parallel transputer-sized units, it's a very effective
way to go.  But dividing up problems for it is difficult, OCCAM notwithstanding.
So it tends to be used as a component of special-purpose 
machines, like CT scanners, signal processing systems, and the like, rather
than as a general-purpose computing element.  This is the typical curse
of moderately-parallel machines.

       See comp.sys.transputer for more info.

					John Nagle