39 ms·
Delay lines are fascinating, but I don't see why this is easier than core memory; seems like you are trading an electronics problem for a mechanical one. Regar
by FullyFunctional 3y ago
Delay lines are fascinating, but I don't see why this is easier than core memory; seems like you are trading an electronics problem for a mechanical one. Regardless, at the speeds they are targeting, I think delay lines might be difficult.
Another interesting option (for ROM) is core rope memory. CuriousMarc has the ultimate explanation: https://www.youtube.com/watch?v=hckwxq8rnr0 https://www.youtube.com/watch?v=hckwxq8rnr0
- Animats 3y agoBecause, if you're using tubes, you don't want a huge number of them. Core memories need many drivers and sense amplifiers. Delay lines are inherently 1-bit devices.
- orbital-decay 3y agoCore memory needs a lot of manual wiring, and you need two demultiplexers to address anything in it. Torsion wire delay line has no demultiplexer and is much simpler; it's basically a coil of invar wire on a spacer, with some rubber dampeners, an actuator, and a sensor. And it's inherently serial, many early calculators had serial architectures built around acoustic or IC delay lines. > at the speeds they are targeting, I think delay lines might be difficult Speed of the torsional wave is around 3000-3500m/s depending on the alloy you use. You can make the coil about several dozen meters long before running into issues (practical torsion wire delay lines were 20 to 80m long). That would give 6 to 27ms of delay, which can keep 600 to 2700 bits in the loop at 100kHz, or 10 times more at 1MHz. The same amount of cores would be far more labor intensive to make.