Question about memory access

18 views

Skip to first unread message

Bill E

unread,

May 6, 2026, 11:44:53 AMMay 6

to [PiDP-1]

I'm sure someone knows... that last example shows the Type 340 running completely autonomously. So, if the PDP-1 is halted, did it still have the ability to access memory, or was memory access also halted? Currently, the 340 will continue running and executing its program even if the main -1 is halted. Correct or should it also halt?

Bill

Bill E

unread,

May 7, 2026, 8:05:17 AMMay 7

to [PiDP-1]

Lacking responses, I think I've figured out that a start, readin, continue, or examine will terminate an in-flight high-speed transfer immediately. This is a bit strange because it means that if something like the drum or a mag tape is in the middle of a transfer, it will be incomplete. However, it's not clear how the 340 behaves. From the detailed description it's implied that it will just wait for the next data word. This additionally implies that the only way to actually stop a 340 autonomous program is by issuing a dla, which is basically the 'reset everything and start running at this address' command. Guidance still needed, but for now if there is a stop via the stop switch or any of the terminating conditions above, the 340 is halted and reset to idle state.