10 May
2018
10 May
'18
9:22 a.m.
On May 10, 2018, at 10:57 AM, Chuck Guzis via cctalk
<cctalk at classiccmp.org> wrote:
On 05/10/2018 07:29 AM, Paul Koning via cctalk wrote:
Faster than a moving head disk, certainly, though head per track disks also existed. DEC
had some fast ones -- RS04 comes to mind.
I looked at the Star peripherals manual. It describes the paging drum as a modified 865
drum, which "rotates at 1800 rpm". So it might have a high transfer rate -- 12
bit words in parallel from 12 heads -- but clearly quite high latency.
paul
I'm wondering what the reality of fast drum
memories looked like, and whether anyone came even close to these numbers. Also, am I
right in thinking they are at least in principle achievable? I know I could run the
stress numbers, but haven't done so.
All of the STAR-100 stations, including the paging station used drums.
Jim Thornton and folks at CDC ADL were working on a 100K RPM drum
spinning in vacuo for a paging store, but they couldn't get it to work
reliably. At any rate, STAR was the last system I saw fast drums on
and you can check the figures in the Bitsavers documentation under
cdc/cyber/cyber200. At any rate, a head-per-track drum could be much
faster than a disk.