alt Hacker News>>> The image is not stored at any point.
The very first computers (Manchester baby) used CRTs as memory - the ones and zeros were bright spots on a “mesh” and the electric charge on the mesh was read and resent back to the crt to keep the ram fresh (a sorta self refreshing ram)
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hahahahhaah • today at 2:47 AM
Why didn't that catch on pre-transistor? Feels like you'd get higher density than valves and relays.
Yes, but those were not the standard kind of CRTs that are used in TV sets and monitors.
The CRTs with memory for early computers were actually derived from the special CRTs used in video cameras. There the image formed by the projected light was converted in a distribution of charge stored on an electrode, which was then sensed by scanning with an electron beam.
Using CRTs as memory has been proposed by von Neumann and in his proposal he used the appropriate name for that kind of CRT: "iconoscope".