8 Jun
2006
8 Jun
'06
11:31 p.m.
On 6/8/2006 at 7:59 PM Billy Pettit wrote:
Billy:
There were several reasons, but the biggest one was: they could do
parallel
read and writes. You could stripe them for 16 bit wide
data paths that
became incredibly fast. And with virtually no bit skew. Plus access time
was never more than one revolution.
Yeah, but in a Star-100 SBU, there was enough memory in the thing that the
drum hardly got used past booting the thing up. There was just no point to
the speed. The Star paged to disk; there were some plans initially for a
huge drum, running something like 512 bits parallel, but I don't know if
the concept ever made it off paper.
The funny thing was that there were the same SBUs on the two Star-1B's in
Sunnyvale--the SBU's were qutie a bit faster than the 1Bs themselves.
(Those two systems eventually went into the dumpster per company policy).
During the 60's, drums gave disks a run for their money. I remember a
Univac 1108 with the very large FASTRAND-II moving-head drum on it.
There were a number of late 50's-early-60's machine with drum as the main
memory, such as the IBM 650 and the LGP-30. "one plus one" addressing.
Cheers,
Chuck