Thank you for saving me the job of linking to TNMoC, they have identical replicas, and occasionally originals, of exactly this kind of project i.e. build a macr

Thank you for saving me the job of linking to TNMoC, they have identical replicas, and occasionally originals, of exactly this kind of project i.e. build a macro-processor. Though most of them predate even transistors. They have one that stores info in a ten-state neon tube which looks as cool as you might hope [see edit]. Turing didn't even have that, they used Acoustic Delay Lines, which could "store" a state for as long as it took a pressure wave to propogate through a long tube. To "write" you do (or do not) send a pulse at the appropriate millionth-of-a-second time slice. To "read" at a certain time later (of the order of a thousandth of a second), listen at the other end in the appropriate millionth-of-a-second time slice for the slightly-degenerated pulse. To store for longer than a thousandth of a second, re-send any detected pulses, and remember which pulses are which. The tube can be filled with anyhting cheap enough, thaat propogates signals as slow as possible, without degenerating them too much. Fun fact, when building the ACE Turing "rather hankered after using gin, which would come cheaper than mercury". Mercury was eventually chosen, hence they're often known as Mercury delay lines. [edit] The machine is called the Harwell Dekatron or WITCH. And it looks and sounds as impressive as its name. See a program being run on it at the link below. Demo starts at 13:00. The spinning lights are the transistor equivalents. Each one able to be read which of the ten possible positions the light is in, and advanced one step. http://www.tnmoc.org/special-projects/harwell-dekatron-witch http://www.tnmoc.org/special-projects/harwell-dekatron-witch