> Because sound moved at a slow rate through a medium like mercury Actually, it moves pretty fast through mercury; 1450 m/s. > each I guess storing one bit. (

> Because sound moved at a slow rate through a medium like mercury Actually, it moves pretty fast through mercury; 1450 m/s. > each I guess storing one bit. (...) Does anyone know if this a correct understanding of how this kind of storage worked? From the Wikipedia article: > Typically many pulses would be "in flight" through the delay, and the computer would count the pulses by comparing to a master clock to find the particular bit it was looking for. > EDSAC, designed to be the first stored-program digital computer, began operation with 512 35-bit words of memory, stored in 32 delay lines holding 576 bits each > The average access time was about 222 microseconds Hmm... That would be a memory loop time of 444 us. At a speed of 1450 m/s, you need a delay line at least 64.38 cm long. And you'd need an impressive 1.3 Mb/s data transmission rate. Another interesting fact: > Since the speed of sound changes with temperature (because of the change in density with temperature) the tubes were heated in large ovens to keep them at a precise temperature. Other systems instead adjusted the computer clock rate according to the ambient temperature to achieve the same effect.