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From: mats@forbrk.UUCP (Mats Wichmann)
Newsgroups: comp.sys.nsc.32k
Subject: Re: NS32000 Processor
Message-ID: <334@forbrk.UUCP>
Date: Wed, 17-Jun-87 10:46:15 EDT
Article-I.D.: forbrk.334
Posted: Wed Jun 17 10:46:15 1987
Date-Received: Sun, 21-Jun-87 10:17:39 EDT
References: <266@udcps1.UUCP> <642@umnd-cs.D.UMN.EDU> <6779@g.ms.uky.csnet> <4399@nsc.nsc.com>
Reply-To: mats@forbrk.UUCP (Mats Wichmann)
Organization: Fortune Systems / SCI Technology  (Berkeley, CA)
Lines: 39

(I am not really sure why Roger's reply bugs me so much, but it just sticks
in my craw to where I have to stick my foot in where it will probably not be 
welcome....)

In article <4399@nsc.nsc.com> roger@nsc.nsc.com (Roger Thompson) writes:
>When IBM was out searching for a micro, our CPU was stable.  What was
>the real decider, your guess is as good as mine.  But it probably had
>more to do with application software being available without
>cumbersome AT&T licenses.
>
My experience was that individual CPU chips were all that was stable. It 
was quite possible to build *a* machine that worked very well. However, 
National sure raised doubts as to being able to ship a stable product in 
volume. At the company I was with, we had decided to go with a combination 
of a different CPU and a National MMU and FP chips. After working with this 
combination for months, we had to give up and throw the National chips out of 
the design. Why? We couldn't get precise specs out of National, and the chips 
did a number of unexplained things. Turns out there were two factors at work - 
the first one was that for whatever reason, National wasn't getting consistent
yeilds, and they liked to give you three-chip sets (CPU, MMU, FP) that had
been hand-picked to make sure they worked together. Any given CPU chip might 
not work with any given MMU chip, etc. This is enough of a deterrent to anybody 
who has to manufacture equipment, and was a killer for us, because we didn't
want the National CPU chip at all. The second factor, the unavailability of
precise timing specs, finally became clear at the end of the cycle - National 
finally admitted that they *couldn't* give us specs because they were still 
changing the CPU to make it work right, and were going to need to change the 
other two chips to match, so they wouldn't commit to any specs on the support 
chips. Motorola sure never pulled anything like that on us!!!

>We had *NIX up and running in 1983.  The first micro with demand paged
>virtual memory.  We are working on our third generation MMU and I'm
>still waiting for your Mot to come up with one customers like SUN
>will use.
>
First? That will get you lots of debate; I suggest you talk to people
at Sun, old-timers at UniSoft, etc.

Mats Wichmann