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

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)