(An Unconventional Guide to Computers) Copyright Information
Mercury Delay Lines as Computer Memory |
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| One of the biggest problems associated with early computers was designing a reliable form of memory. A variety of esoteric techniques were employed, of which a relatively successful contender was that of mercury delay lines. | ||
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| These delay lines were constructed using a thin tube of mercury sealed with quartz crystals at each end. Applying an electric current to a quartz crystal causes it to vibrate. Similarly, vibrating a quartz crystal causes it to generate an electric current. The principle behind the mercury delay line was to briefly apply a current to the crystal at one end of the tube, which generated a pulse that propagated through the mercury at a known speed. When the pulse reached the far end of the delay line, it caused the crystal at that end to generate a corresponding current. | By amplifying the output from the second crystal and feeding it back to the first crystal, a continuous loop could be established. Moreover, a number of individual pulses could be maintained in a single delay line, similar in concept to a column of people marching down a corridor in single file. In fact 1000 bits could be stored in a delay line 5 feet long. | |
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| These notes are abstracted from the book Bebop BYTES Back (An Unconventional Guide to Computers) Copyright Information |
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