Computers That Stored Data In Sound

Early computers once stored data by turning electrical signals into sound pulses traveling through tubes of liquid. Because the data moved in a physical loop, the machine had to wait for the sound wave to circle back to be read again.

Before silicon chips, engineers used mercury-filled tubes to hold bits of information. A pulse would travel down the tube as an ultrasonic wave, hit a sensor at the end, and get sent right back to the start. It was essentially a digital game of keep-away that kept memory constantly in motion. Today, this concept is seeing a high-tech comeback in optical systems using light instead of sound.