eolas/neuron/d64aa559-4490-4b05-bfd9-4fd535f23109/Williams_Tube_memory.md

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2024-12-09 18:34:15 +00:00
---
tags: [computer-history, memory]
created: Tuesday, September 17, 2024
---
# Williams Tube memory
- One of the early attempts to create RAM in computers based on the EDVAC
stored-program architecture.
- Worked by displaying a grid of dots on a cathode-ray tube ("screen")
- Due to the way CRTs work, this creates a small charge of static electricity
over each dot. The charge at the location of each of the dots is read by a
thin metal sheet just in front of the display.
- Each dot position could be written to and read from and the pattern was
constantly refreshed as the dots would fade over time.
![A Williams CRT tube](static/williams-tube.jpg)
![Memory dot pattern from a Williams Tube](static/williams-tube-dots.jpg)