Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Stephen Fuld <sfuld@alumni.cmu.edu.invalid>
Newsgroups: comp.arch
Subject: Re: what's a mainframe, was is Vax addressing sane today
Date: Wed, 11 Sep 2024 11:25:48 -0700
Organization: A noiseless patient Spider
Lines: 65
Message-ID: <vbsnbc$f01n$4@dont-email.me>
References: <vbd6b9$g147$1@dont-email.me>
 <2024Sep11.113204@mips.complang.tuwien.ac.at> <vbsg1v$1lt4$1@gal.iecc.com>
 <vbsjdk$f01n$3@dont-email.me> <vbsl9j$2r0b$1@gal.iecc.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Wed, 11 Sep 2024 20:25:49 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="6a662a8a00c851f8c26756079048eecd";
	logging-data="491575"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18yzL5DtPrdZXUpfkejrmzFpd/ipPgXCXw="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:TAQQBKsOPOKleToWWdFGRvNeQrw=
Content-Language: en-US
In-Reply-To: <vbsl9j$2r0b$1@gal.iecc.com>
Bytes: 3599

On 9/11/2024 10:50 AM, John Levine wrote:
> According to Stephen Fuld  <sfuld@alumni.cmu.edu.invalid>:
>>> IBM definitely cared about maximum performance in the 1950s and early
>> 1960s.
>>
>> Yes.  And remember, one of the goals of S/360 was to provide an
>> architecture that could handle both scientific (i.e. compute bound) and
>> business (i.e. I/O bound) workloads.
> 
> I don't think anyone would have forseen how quickly scientific computing
> moved to mini and micro computers with fast CPUs and weak peripherals.

Agreed, plus the development of CDC/Cray supercomputers that took the 
high end scientific market away from IBM.



> Perhaps once the RAM is big enough to hold all the data the I/O performance
> is not a big deal.
> 
>>> 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.
>>
>> Mostly true, except for the 3090 vector facility.
> 
> I suppose.  A review from the USDOE said:
> 
>   The IBM 3090 with Vector Facility is an extremely interesting machine
>   because it combines very good scaler performance with enhanced vector
>   and multitasking performance. For many IBM installations with a large
>   scientific workload, the 3090/vector/MTF combination may be an ideal
>   means of increasing throughput at minimum cost. However, neither the
>   vector nor multitasking capabilities are sufficiently developed to
>   make the 3090 competitive with our current worker machines for our
>   large-scale scientific codes.
> 
> https://www.osti.gov/biblio/5039931

I didn't claim that the 3090VF was successful, just that IBM was 
interested enough in the scientific market to spend money developing it 
after the 370/195.



> 
>>> 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.
>>
>> Yes, but they also have to keep producing faster and faster CPUs so they
>> can entice current customers to upgrade and thus meet their revenue goals.
> 
> The memories and disks keep getting bigger so it's not totally silly to
> think that the CPUs need to get faster, too. 

Agreed, of course.



-- 
  - Stephen Fuld
(e-mail address disguised to prevent spam)