Re: what's a mainframe, was is Vax addressing sane today

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Sujet : Re: what's a mainframe, was is Vax addressing sane today
De : johnl (at) *nospam* taugh.com (John Levine)
Groupes : comp.arch
Date : 11. Sep 2024, 17:21:19
Autres entêtes
Organisation : Taughannock Networks
Message-ID : <vbsg1v$1lt4$1@gal.iecc.com>
References : 1 2 3 4
User-Agent : trn 4.0-test77 (Sep 1, 2010)
According to Anton Ertl <anton@mips.complang.tuwien.ac.at>:
Lawrence D'Oliveiro <ldo@nz.invalid> writes:
On Tue, 10 Sep 2024 16:32:05 GMT, Anton Ertl wrote:
>
It seems that during the late 1990s, IBM was not particularly interested
in mainframe per-CPU performance.
>
Mainframes were never about CPU performance.
>
The S/360 Model 91 and the Model 195 certainly were about the maximum
CPU performance.  And I doubt that IBM would have spent all the effort
with ECL and a superscalar OoO implementation for some of the ES/9000
machines if CPU performance was considered unimportant at the time.
>
It's an interesting question why they did not follow up their
superscalar OoO ECL implementations with a superscalar OoO CMOS
implementation in addition to the scalar in-order 9672. ...

IBM definitely cared about maximum performance in the 1950s and early 1960s.

The goal of STRETCH was specifically to make the fastest possible computer. It sort of
succeeded, late and over budget and not as fast as they hoped, but still the fastest
computer in the world for a while. It was a success in that they reused a lot of the
technology like the fast core memory in later computers.

The 360/91 was also intended to be the fastest possible computer, which again it sort of
was, late and over budget. One thing that STRETCH and the /91 shared was that they were
extremely complicated. STRETCH had variable sized bytes and and addressing modes that I
never entirely figured out. The /91 had an instruction queue with loop mode and out of
order operations and register renaming and imprecise interrupts. When the CDC 6600 came
out, a much simpler design from a tiny company that was nonetheless faster than the /91,
they knew they had a problem. The /95 and /195 were minor upgrades of the /91 but that was
the end of their supercomputer efforts.

The point of a mainframe is balanced performance. The CPU of a 360/30 was extremely slow
but it was fast enough to drive a disk or two and a printer and card read/punch and get a
lot of useful work done. Mainframes have had channels since the 709 in the late 1950s so
they have a lot of I/O capacity.  Modern ones have terabytes of RAM and exabyte of disk.

They also care deeply about reliability. Modern mainframes have multiple kinds of error
checking and standby CPUs that can take over from a failed CPU, restart a failed
instruction, and the program doesn't notice.  I think you'll find a pattern since the
CDC shock of making CPUs fast enough to keep the RAM and I/O devices busy while having
the error checking and recovery features so the systems keep running for years at a time.



--
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

Date Sujet#  Auteur
5 Sep 24 * is Vax adressing sane today336Brett
5 Sep 24 +* Re: is Vax adressing sane today324John Dallman
6 Sep 24 i+- Re: is Vax adressing sane today1Lawrence D'Oliveiro
6 Sep 24 i`* Re: is Vax adressing sane today322Anton Ertl
6 Sep 24 i +- Re: is Vax adressing sane today1Lawrence D'Oliveiro
6 Sep 24 i +* Re: is Vax adressing sane today5MitchAlsup1
7 Sep 24 i i`* Re: is Vax adressing sane today4Anton Ertl
7 Sep 24 i i `* Re: is Vax adressing sane today3Anton Ertl
7 Sep 24 i i  `* Re: is Vax addressing sane today2John Dallman
7 Sep 24 i i   `- Re: is Vax addressing sane today1Anton Ertl
7 Sep 24 i +* Re: is Vax adressing sane today313John Levine
8 Sep 24 i i`* Re: is Vax adressing sane today312Anton Ertl
8 Sep 24 i i +* Re: is Vax adressing sane today304MitchAlsup1
8 Sep 24 i i i`* Re: is Vax addressing sane today303Lawrence D'Oliveiro
9 Sep 24 i i i +* Re: is Vax addressing sane today231MitchAlsup1
9 Sep 24 i i i i`* Re: is Vax addressing sane today230Brett
9 Sep 24 i i i i +* Re: is Vax addressing sane today7MitchAlsup1
10 Sep 24 i i i i i`* Re: is Vax addressing sane today6Niklas Holsti
11 Sep 24 i i i i i +- Re: is Vax addressing sane today1Lawrence D'Oliveiro
25 Sep 24 i i i i i `* Re: is Vax addressing sane today4Stephen Fuld
25 Sep 24 i i i i i  `* Re: is Vax addressing sane today3Michael S
25 Sep 24 i i i i i   `* Re: is Vax addressing sane today2MitchAlsup1
25 Sep 24 i i i i i    `- Re: is Vax addressing sane today1Niklas Holsti
10 Sep 24 i i i i `* Re: is Vax addressing sane today222Anton Ertl
10 Sep 24 i i i i  +* Re: is Vax addressing sane today4Michael S
10 Sep 24 i i i i  i`* Re: is Vax addressing sane today3Anton Ertl
10 Sep 24 i i i i  i +- Re: is Vax addressing sane today1Niklas Holsti
11 Sep 24 i i i i  i `- Re: is Vax addressing sane today1Michael S
11 Sep 24 i i i i  +* Re: is Vax addressing sane today7Lawrence D'Oliveiro
11 Sep 24 i i i i  i`* Re: is Vax addressing sane today6Michael S
11 Sep 24 i i i i  i `* Re: is Vax addressing sane today5David Brown
11 Sep 24 i i i i  i  +* Re: is Vax addressing sane today2Thomas Koenig
11 Sep 24 i i i i  i  i`- Re: is Vax addressing sane today1David Brown
11 Sep 24 i i i i  i  `* Re: is Vax addressing sane today2David Schultz
13 Sep 24 i i i i  i   `- Re: is Vax addressing sane today1David Brown
11 Sep 24 i i i i  +* Re: is Vax addressing sane today5John Levine
11 Sep 24 i i i i  i`* Re: is Vax addressing sane today4Thomas Koenig
11 Sep 24 i i i i  i +* Re: is Vax addressing sane today2Anton Ertl
11 Sep 24 i i i i  i i`- Re: is Vax addressing sane today1jseigh
11 Sep 24 i i i i  i `- Re: is Vax addressing sane today1John Levine
20 Sep 24 i i i i  `* Re: is Vax addressing sane today205Kent Dickey
21 Sep 24 i i i i   +* Re: is Vax addressing sane today4MitchAlsup1
21 Sep 24 i i i i   i`* Re: is Vax addressing sane today3Lawrence D'Oliveiro
21 Sep 24 i i i i   i `* Re: is Vax addressing sane today2MitchAlsup1
21 Sep 24 i i i i   i  `- Re: is Vax addressing sane today1Lawrence D'Oliveiro
21 Sep 24 i i i i   +* Re: is Vax addressing sane today4Lawrence D'Oliveiro
21 Sep 24 i i i i   i`* Re: is Vax addressing sane today3MitchAlsup1
21 Sep 24 i i i i   i +- Re: is Vax addressing sane today1Niklas Holsti
21 Sep 24 i i i i   i `- Re: is Vax addressing sane today1Lawrence D'Oliveiro
21 Sep 24 i i i i   +* Re: is Vax addressing sane today30MitchAlsup1
22 Sep 24 i i i i   i+* Re: except what, is Vax addressing sane today18John Levine
22 Sep 24 i i i i   ii+- Re: except what, is Vax addressing sane today1Michael S
22 Sep 24 i i i i   ii+* Re: except what, is Vax addressing sane today8Lawrence D'Oliveiro
22 Sep 24 i i i i   iii`* Re: except what, is Vax addressing sane today7Chris M. Thomasson
22 Sep 24 i i i i   iii `* Re: except what, is Vax addressing sane today6MitchAlsup1
22 Sep 24 i i i i   iii  +* Re: except what, is Vax addressing sane today2Lawrence D'Oliveiro
22 Sep 24 i i i i   iii  i`- Re: except what, is Vax addressing sane today1MitchAlsup1
22 Sep 24 i i i i   iii  +- Re: except what, is Vax addressing sane today1Chris M. Thomasson
22 Sep 24 i i i i   iii  `* Re: except what, is Vax addressing sane today2John Dallman
22 Sep 24 i i i i   iii   `- Re: except what, is Vax addressing sane today1MitchAlsup1
22 Sep 24 i i i i   ii+* Re: except what, is Vax addressing sane today5Terje Mathisen
24 Sep 24 i i i i   iii`* Re: except what, is Vax addressing sane today4Lawrence D'Oliveiro
24 Sep 24 i i i i   iii `* Re: except what, is Vax addressing sane today3Chris M. Thomasson
24 Sep 24 i i i i   iii  `* Re: except what, is Vax addressing sane today2MitchAlsup1
16 Oct 24 i i i i   iii   `- Re: except what, is Vax addressing sane today1Chris M. Thomasson
22 Sep 24 i i i i   ii`* Re: except what, is Vax addressing sane today3Lars Poulsen
24 Sep 24 i i i i   ii `* Re: except what, is Vax addressing sane today2Lawrence D'Oliveiro
24 Sep 24 i i i i   ii  `- Re: except what, is Vax addressing sane today1Michael S
22 Sep 24 i i i i   i+* Re: is Vax addressing sane today7Lawrence D'Oliveiro
22 Sep 24 i i i i   ii`* Re: is Vax addressing sane today6MitchAlsup1
22 Sep 24 i i i i   ii +* Re: is Vax addressing sane today3Lawrence D'Oliveiro
22 Sep 24 i i i i   ii i`* Re: is Vax addressing sane today2MitchAlsup1
22 Sep 24 i i i i   ii i `- Re: is Vax addressing sane today1Lawrence D'Oliveiro
22 Sep 24 i i i i   ii `* Re: is Vax addressing sane today2Anton Ertl
24 Sep 24 i i i i   ii  `- Re: is Vax addressing sane today1MitchAlsup1
24 Sep 24 i i i i   i+* Re: is Vax addressing sane today2Stefan Monnier
24 Sep 24 i i i i   ii`- Re: is Vax addressing sane today1MitchAlsup1
25 Sep 24 i i i i   i+- Re: is Vax addressing sane today1MitchAlsup1
12 Oct 24 i i i i   i`- Re: is Vax addressing sane today1Anton Ertl
22 Sep 24 i i i i   +* Re: is Vax addressing sane today4Thomas Koenig
24 Sep 24 i i i i   i`* Re: is Vax addressing sane today3Kent Dickey
24 Sep 24 i i i i   i +- Re: is Vax addressing sane today1Bill Findlay
24 Sep 24 i i i i   i `- Re: is Vax addressing sane today1Thomas Koenig
23 Sep 24 i i i i   +- Re: is Vax addressing sane today1Stefan Monnier
23 Sep 24 i i i i   `* Re: is Vax addressing sane today161Kent Dickey
24 Sep 24 i i i i    +* Re: is Vax addressing sane today11MitchAlsup1
24 Sep 24 i i i i    i+- Re: is Vax addressing sane today1Lawrence D'Oliveiro
24 Sep 24 i i i i    i`* Re: is Vax addressing sane today9Terje Mathisen
24 Sep 24 i i i i    i +* Re: is Vax addressing sane today4Michael S
24 Sep 24 i i i i    i i`* Re: is Vax addressing sane today3Terje Mathisen
24 Sep 24 i i i i    i i `* Re: is Vax addressing sane today2Michael S
24 Sep 24 i i i i    i i  `- Re: is Vax addressing sane today1MitchAlsup1
24 Sep 24 i i i i    i +* Re: is Vax addressing sane today3Stephen Fuld
24 Sep 24 i i i i    i i`* Re: is Vax addressing sane today2MitchAlsup1
25 Sep 24 i i i i    i i `- Re: is Vax addressing sane today1Stephen Fuld
12 Oct 24 i i i i    i `- Re: is Vax addressing sane today1Anton Ertl
24 Sep 24 i i i i    +* Re: is Vax addressing sane today3Terje Mathisen
29 Sep 24 i i i i    i+- Re: is Vax addressing sane today1Michael S
7 Oct 24 i i i i    i`- Re: is Vax addressing sane today1Kent Dickey
25 Sep 24 i i i i    +* Re: is Vax addressing sane today133MitchAlsup1
26 Sep 24 i i i i    i+- Re: is Vax addressing sane today1MitchAlsup1
28 Sep 24 i i i i    i`* Re: is Vax addressing sane today131Lawrence D'Oliveiro
28 Sep 24 i i i i    +* Re: is Vax addressing sane today3George Neuner
7 Oct 24 i i i i    +* Re: is Vax addressing sane today8Kent Dickey
12 Oct 24 i i i i    `* Re: is Vax addressing sane today2Anton Ertl
9 Sep 24 i i i `* Re: is Vax addressing sane today71Anton Ertl
8 Sep 24 i i `* Re: is Vax adressing sane today7Brett
8 Sep 24 i `* Re: is Vax adressing sane today2MitchAlsup1
6 Sep 24 +* Re: is Vax adressing sane today2MitchAlsup1
6 Sep 24 +- Re: is Vax adressing sane today1Lawrence D'Oliveiro
6 Sep 24 `* Re: is Vax adressing sane today8Anton Ertl

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