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 minutes. 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: http://techno-science.ca/en/collection-research/collection-item.php?id=1982.0057.001 Technical reference manual: http://bitsavers.informatik.uni-stuttgart.de/pdf/litton/Litton1600_TechnicalRefMan.pdf Bit serial architecture, of course. An odd bird, if there ever was one. --Chuck
