Transporting an LGP-30

Chuck Guzis cclist at
Fri Dec 30 14:14:24 CST 2016

On 12/30/2016 09:49 AM, Paul Koning wrote:

> I have an old set of lecture notes I'm translating, for a course on
> computer design from 1948, which discusses various memory types.  Not
> core memory, that came later.  But it mentions drums, and theorizes
> that those might be operated at 60,000 rpm...  I'm not sure where
> that optimism came from.  Perhaps because the author was a
> mathematician rather than a mechanical engineer?

CDC ADL back in the late 1960s was testing a prototype high-speed drum
for the STAR--100K RPM in vacuo, ISTR.   Probably a Jim
Thornton-inspired scheme.  I do recall Neil Lincoln mentioning that the
observation window became coated with drum material in the first few

The idea was a very fast paging store.  That and the SCROLL tape/disk
device are two that come to mind.

Anent the LGP30--some drums were equipped with several heads spaced
around the same track to cut down on latency.

Logic need not be vacuum-tube or transistor--I recall the Univac Solid
State machines that used magnetic core as well as the Parametrons of NEC.

Drum machines persisted a bit longer than one would expect; e.g., the
Litton 1601 was produced in the early 70s.

A photo:

Technical reference manual:

Bit serial architecture, of course.  An odd bird, if there ever was one.


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