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From: anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups: comp.arch
Subject: IBM and Amdahl history (Re: What is an N-bit machine?)
Date: Fri, 29 Nov 2024 07:22:28 GMT
Organization: Institut fuer Computersprachen, Technische Universitaet Wien
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Lynn Wheeler <lynn@garlic.com> writes:
>jgd@cix.co.uk (John Dallman) writes:
>Circa 1971, Amdahl gave talk in large MIT auditorium and somebody in the
>audience asked him what justifications he used to attract investors and
>he replied that even if IBM were to completely walk away from 370, there
>was hundreds of billions in customer written 370 code that could keep
>him in business through the end of the century.

And that was probably an understatement.  Legacy software is keeping
Unisys in business to this day, and the software ecosystem and
customer base of S/360 was larger in 1971 than the Burroughs large
systems and Univac lines that Unisys is still working with AFAIK.

OTOH, Amdahl corporation did not make it until the end of the century
(at least not on its own; it became a subsidiary of Fujitsu), for two
reasons having to do with IBM not walking away from the S/360 family:

1) IBM made the switch to CMOS and benefitted from the extremely fast
speedups in CMOS speed in the 1990s, while Amdahl failed to take that
step.

2) IBM extended the 32-bit s390 to the 64-bit s390x in 2000.
Fujitsu/Amdahl did not want to follow and essentially gave up that
market.

>At the time, IBM had the "Future System" project that was planning on
>doing just that ... and I assumed that was what he was referring to
>... however in later years he claimed that he never had any knowledge
>about "FS" (and had left IBM before it started).
>
>trivia: during FS, internal politics was killing off 370 projects and
>claims are the lack of new 370 products in the period is what gave the
>clone 370 makers (including Amdahl) their market foothold. some more
>info
>http://www.jfsowa.com/computer/memo125.htm
>when FS finally imploded, there was mad rush to get stuff back into the
>370 product pipelines, including kicking off the quick&dirty 3033&3081
>efforts.

OTOH, FS eventually led to S/38 and the System i, which IBM sold
rather than introducing low-end S/370 (and later s390 and s390x)
members.  The way that Heinz Zemanek (head of IBM's Vienna Lab until
1976) told the story was that IBM was preparing to be divided up if
they lost the anti-trust action, and introduced S/38 and one other
line (that I don't remember) in addition to S/370 for that.

- anton
-- 
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>