> On Sep 23, 2022, at 2:25 PM, Chuck Guzis via cctalk <cctalk@classiccmp.org>
> wrote:
>
> On 9/23/22 10:52, ben via cctalk wrote:
>
>> Just how do the supercomputer do i/o for all that floating numbers.
>> Weather maps I can see for output, but what about all that Top Secret
>> number crunching.
>
> Well, consider the 1969 STAR-100; although not well documented, had a
> 512-bit wide, error-checked I/O channel that ran at memory speed. Neil
> had various schemes for it, including a 100K RPM head-per-track drum
> that ran in vacuo. I recall him mentioning that the prototype lasted
> around a minute before the observation window was covered with the
> remnants of the drum surface.
There is of course the CDC 6000 series ECS and its successors, a bulk memory
that does block transfers to/from main memory at full memory speed.
Re 100k drum, interesting that someone tried to build that. It might actually
work as a disk, with floating heads in low pressure air rather than vacuum.
But it reminds me of a computer design course from 1948, where a discussion of
memory technologies postulates a drum memory (main memory in that era)
described as "8 cm diameter and a few decimeters long" spinning at 60k RPM to
deliver an average latency of 50 microseconds. It is perhaps significant
Adriaan van Wijngaarden, the author of that document, was a mathematician
rather than a mechanical engineer. :-)
> Or consider the STAR SCROLL--a very wide tape that ran over a
> head-per-track drum. I don't recall seeing that prototype; maybe it
> existed only in the mind. But we had to mention both in our responses
> to RFQs.
Shades of the CDC 626, a one inch wide 14 track tape drive. That was a real
product, I think, though I never ran into one.
Another way to get high speed: one of CDC's first disk drives, the 6603, wrote
several bits in parallel. 4 bits? 12? I don't remember, but it made for a
throughput spec that was unbeaten for nearly a decade.
paul
