17 Jul
2001
17 Jul
'01
1:08 p.m.
I'm curious how that CDC system figured out where
I was pointing the light
pen when I selected a component from the menu, which was at the right
margin of the screen, and placed it on the screen.
Those big tubes were storage...
Storage tubes could display in non stored mode. If the write beam was
below a threshold it wouldn't store, and would need to be refreshed.
The 'refreshment' generated the necessary timing signal. Menus were
probably always non-stored for that reason.
John A.