Path: utzoo!mnetor!uunet!yale!wallman-george
From: wallman-george@CS.Yale.EDU (Natuerlich!)
Newsgroups: comp.sys.atari.st
Subject: Re: transputer
Message-ID: <28201@yale-celray.yale.UUCP>
Date: 29 Apr 88 19:54:42 GMT
Sender: root@yale.UUCP
Reply-To: wallman-george@CS.Yale.EDU (Natuerlich!)
Organization: Natuerlich!'s Software Vault #5 -- Location Yale
Lines: 58
Keywords: process communication parallel Yeah!

>dan writes
>MIPS per processor.  The real issue is parallelism, virtually unlimited
>parallelism; and the transputer has it.
> [DELETIONS]
>I feel bad about chastising the people who site the lack of an MMU as a
>liability.  They seem the closest to understanding the things that are
>really important!  'tis true, without an MMU 'virtual memory' is not
>going to be feasible. The ABAQ is suppose to implement a greater goal,
>_Virtual_Processors_.  Each task doesn't get just its own memory to muck
>about in, without worry; but its own processor (and anything on that
>processor) to muck with.
> [DELETIONS]
>	dan
Natuerlich! welcomes the insight that parallel processing is indeed the
way, I hope many more people would share that. A 68030 box is a dead
end and probably not enough power past 1995 AD. A transputer is 
expandable hurray!. 

But but but. Limiting the OS to run as many processes
as there are processor is no step forward. Even if each processor gets
1MB space (sounds about right for a personal computer) and we have four
processors. Would we like to waste 1MB for my printer spooler,
1MB for the little iconized clock in the upper-left corner of my screen
and so on ? Of course not. We wan't to have the processors multitasking
as well. Process space is swapped into the processors local area executed
swapped out etc. that needs at least one humongous MMU or lots of little
per processor MMU. But from my (possible limited viewpoint) I don't
see a way around a MMU. (*) And I don't see how a modified UNIX couldn't do 
the job as the governing OS as well. (**)
I mean of course you can't compile  plain vanilla BSDxy and hope that 
that would work instantly. 
I strongly believe that a vendor like Atari who comes out with an 
incompatible OS and no major backing (like the Defense Dept. or IBM 
(or is that the same ?) ) will even with super-duper superior hardware 
make no dent in the workstation/upscale-personal-computer market.
If though the OS  *IS*  Unix (***) I see indeed a good possibility that
something will move.

In conclusion : Would someone like to tell me how process management/
                communication under HELIOS will work ?

Natuerlich!

(*)   Except if the transputer can generate the necessary bus
      errors itself to implement VM completely in software. Or
      by my oversight the chip already has some MMU capabilities.
      
(**)  To keep the machine hopping I'd envision one processor
      dedicated to OS use only,  communication via message
      passing... 

(***) Ooops I wrote Unix instead of Un*x, what nasty things might
      possibly happen to me now ? 
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