26 May
2005
26 May
'05
9:35 a.m.
>>>> "Vintage" == Vintage
Computer Festival <vcf at siconic.com> writes:
Vintage> On Thu, 26 May 2005, Paul Koning wrote:
Al> Or magnetic drums, which did NOT have the access time problems of
Al> tape or cards (but, unfortunately weren't an IBM invention)
> Did the drum come before RAMAC?
Vintage> Yes. Many years (I believe about six).
> An obvious difference is that drums, being head
per track devices,
> always had rather low capacity.
Vintage> And disks are much more efficient than drums anyway.
I don't think head per track disks are necessarily any more efficient
than head per track drums. They overlapped somewhat in time, and I
think the capacity was reasonably comparable.
Moving head disks are far more efficient because you can put down a
lot more tracks, even in the very early days, than is reasonable on a
head per track ("fixed head") disk or drum. Consider the early 1960s
1311 with 100 tracks, vs. the RF11 with (if I remember right) 32
tracks.
paul