Delay Line Memory (Was: Australian ex-DEC Director has large museum in his home)
uban at ubanproductions.com
Wed Dec 3 10:37:39 CST 2008
Rick Bensene wrote:
> Delay lines were used a lot in early electronic calculators from the
> around 1963 through the early 1970's, by which time MOS integrated
> circuits (first shift registers, then RAM) took over.
> Delay lines were used extensively in early electronic calculators by
> Olivetti, Canon, Friden, and Sony, among others.
> Typically the delay line was used to store the working registers of the
> calculator, with the data continuously circulating through the delay
> line and the arithmetic/display logic. Most of the delay lines used in
> calculators were of the magnetostrictive type, which used thin tapes of
> nickel (which contract when subjected to a magnetic field), that impart
> torque twists into a special wire that served as the delay medium. This
> wire was strung in a spiral, with lengths ranging up to around 50 feet.
> Magnetostrictive transducers were affixed to each end of the wire, with
> one end being the transmitter, and the other the receiver. Capacity of
> the delay line was a function of the length of the loops of wire, and
> the data rate pushed through the delay line. In the Friden 130, the
> first production calculator to use a delay line, the delay line wire is
> about 50 feet long, and the delay is about 5ms, with 480 "bits" of
> information stored in the delay line. Typically, delay line memories
> in calculator implementations max out at around 1500 bits of storage.
> Programmable calculators, like the Monroe EPIC 2000/3000, the Olivetti
> Programma 101 and follow-on machines, and some Canon programmables had
> the highest capacity delay lines since the line needed to store both the
> working registers of the calculator, as well as the user's stored
> program. In the case of the Monroe EPIC 2000/3000, two delay lines were
> used (housed in the same enclosure), one for working register storage,
> and the other for program storage.
Are delay lines of this type subject to errors induced by vibrations
or shock? If so, would heavy handed typing on the calculator's keys
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