Front panel switches - what did they do?
mouse at Rodents-Montreal.ORG
Tue May 24 12:06:31 CDT 2016
>>> The PDP-5 I did a fair bit of work on needed a bootstrap program
>>> loaded in from switches, it had no internal ROM for that.
>> How long did it usually take to do it?
> We had contests, I think some people got under 15 seconds.
> All from memory, of course!
I don't think I ever used a PDP-5, but I did, back in the late '70s,
use some HP rackmount machine with lighted buttons for front-panel
switches and a manually-entered bootstrap. I got good at entering its
bootstrap, to the point where the limiting factor was speed of moving
my fingers between switches; once the code was memorized, dexterity was
the limiting factor for speed. (I don't remember how long the
bootstrap was; I think it was something like six or eight instructions.
Probably something like "set DMA address and source sector in disk
controller, tell disk controller to read, wait for completion, jump to
loaded code". Probably only some five or ten seconds to enter.)
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