---
title: Delay_line_memory
tags: [computer-history, memory]
created: Wednesday, September 18, 2024
---

# Delay line memory

- First described in the _First Draft_ by #vonNeumann based on work by Eckert
  and Mauchley.

- Information is stored as acoustic waves travelling through a medium, typically
  mercury. As sound travels more slowly than electric charge (light), if
  electric signals are converted to sound, the delay time involved can be used
  as a type of store.

- It worked as follows:
  - Imagine we have an 8-bit number. The number is input as a sequence of pulses
    where a pulse is 1 and the absence of a pulse is 0.
  - The pulses are converted into sound waves (as with a speaker) and sent
    through a mercury-filled tube.
  - The length of the tube is calculated...