4 ms·
I've always wondered, what _are_ those large groovy switches on the front? They're just numbered with integers [0..21, colored in groups of 3 presumably for oc
by crispyambulance 8y ago
I've always wondered, what _are_ those large groovy switches on the front?
They're just numbered with integers [0..21, colored in groups of 3 presumably for octal]! are they seriously for bit flipping??
- NegativeLatency 8y agoYes: http://www.psych.usyd.edu.au/pdp-11/bootstraps.html http://www.psych.usyd.edu.au/pdp-11/bootstraps.html
- dboreham 8y agoThat's a "Front Panel" and all computers prior to around 1980 had one. It's the equivalent of the BIOS -- the one thing that's up and running when the power switch is flipped on. If the machine had core memory (which was non-volatile) the FP was seldom needed since the primary boot loader would be left in core long-term (after being toggled in once).
- OliverJones 8y ago21 bits ... allows front panel access to more than the 16 bits of the machine registers. smokin'!
- ch_123 8y agoThe /70 had a 22-bit address bus, so I assume that switches 16-21 didn't have any effect unless you were entering a memory address.
- timbit42 8y agoYes. They are bit numbers.
- walshemj 8y agonope you loaded code in as OCD octal coded decimal to boot the system if the bootstrap processor failed or was not present
- IvyMike 8y agoHere's a demo of someone using these switches to enter and run programs on a PiDP-8. https://www.youtube.com/watch?v=oMRDAD1JNWo https://www.youtube.com/watch?v=oMRDAD1JNWo