Tech Talk: Delay Lines
Advances in radar during World War II had an unanticipated spinoff: delay lines as computer memory.
Delay lines were developed to store radar blips so that screens displayed only new, moving blips. In computers, delay lines converted data bits (ones and zeros) into sound waves, transmitted them acoustically, then converted them back into bits. They circulated forever until changed by the computer.
Mercury-filled tubes had transducers at the ends to generate and receive bits. In magnetostrictive delay lines, an electromagnet twisted a long wire one way or the other to represent ones or zeros.
Maurice Wilkes designed the EDSAC, one of the earliest stored-program computers, which used delay line memory.View Artifact Detail
Mercury delay line memories were initially developed for WWII radar systems.View Artifact Detail
Sirius was a small, low-cost business computer using a simple programming language. Its main memory was a magnetostrictive delay line.View Artifact Detail