12 Apr
2024
12 Apr
'24
1:13 p.m.
On Apr 12, 2024, at 3:25 PM, Chuck Guzis via cctalk
<cctalk(a)classiccmp.org> wrote:
On 4/12/24 12:04, Paul Koning via cctalk wrote:
Yes, the Univac Model I acoustic delay line memories. The document I mentioned is MC
report CR-3, by A. van Wijngaarden, 1948, which is online in their archive but only as a
not particularly clear scanned document in Dutch. It describes six memory technologies:
photographic film, fluorescence, electric resistance (including the notion of a neon
cross-bar, which is another way of describing Bitzer's inherent-memory plasma display
panel but more than a decade earlier), acoustic waves (such as the Univac memory),
magnetic tape, wire, or drum storage, and electrostatic charges (the Selectron is
described in detail).
Not all that fast, well, it depends on what you're comparing with. Given tube logic
with cycle times measures in microseconds, quite possibly serial rather than parallel
organization, those acoustic or drum memory systems weren't all that terrible.
paul
I remember a concept for a very fast magnetic
storage system that didn't become a product, as far as I know. The scheme was to
build a large array of heads, using IC-manufacturing type techniques, and mount that array
in contact or near-contact with a flat rectangular magnetic plate. The plate (or the
heads) could move a small amount in one direction. The idea was "head per
sector", with the mechanical motion scanning the sector across the head. Given
something like piezo-electric actuators it would have been quite fast.
There's a neat document in the CWI archives, a course on computer design from early
1948. It has a section about memories, well before core memory was invented. The schemes
it describes are quite curious, including photographic memories, selectrons, and various
other schemes. Also drum memories, including the rather mythical notion of a drum
spinning at 60,000 rpm.
That UNIVAC nickel-plated sewer pipe in a box, the Fastrand II used a
series of solenoids and lever arms for head positioning. I vaguely
remember a FJCC article describing it.
But fast? Not so much, at least for drum storage of that era. I
believe there were also microphones incorporated into it, called "ping
detectors"....