Interesting part

I don't know specifically what this one is, but I can say that magnetostrictive delay line technology was very common in early electronic calculators. These devices used magnetostrictive 'tapes', which would change length when a magnetic field is applied. These tapes served as transducers which were connected to the ends of a long coil of special wire, into which acoustic pulses were launched. The pulses would travel to the other end of the coil of wire, and be picked up by a similar transducer at the other end. Most calculators would need to store between 128 and 2048 bits, and ran at clock rates between 30KHz to 500KHz. Many interesting schemes were used to initialize the memory, as well as synchronizing and re-timing data as it circulated through the delay line. The delay lines were relatively temperature stable, but were susceptible to mechanical shock. I've had a number of cases where you could really confuse a calculator by simply sharply tapping the case of the delay line. This technology was actually used into the early 1970's, as it was inexpensive compared to other technologies such as discrete transistor flip flops, magnetic core memory, small-scale IC flip flops, and small magnetic drum memory. Even by the early '70's, when MOS IC technology started to become mainstream, the delay lines were still more cost effective than MOS shift registers. But, by '72 and '73, when Large Scale Integration (LSI) devices became mainstream, the era of the magnetostrictive delay line came to an end. There are lots of examples of calculators with magnetostrictive memory (Friden was a frequent user of the technology) on my "Old Calculator Web Museum" website at http://oldcalculatormuseum.com Rick Bensene The Old Calculator Web Museum Sellam wrote: