PDP1 LISP

[John Stout]

Has anyone got LISP working on their PiDP-1? 

I've tried following Oscar's instructions at Lisp programming on the PDP-1 so

1. Set the Extend switch
2. Mount the lisp.rim tape and press READ IN.
3. Set the TW switches to 7750 and press CONTINUE,
4. Set the TW switches to 400 and press CONTINUE,
5. Set Sense Switch 5 and press CONTINUE a third time.

Typing NIL<space> echoes to the screen but doesn't do anything.

Running test.sh convinces me that all the switches are working, at least flipping them up/down produces a change, and I can run the games (spent a great hour or so with my grandson playing Spacewar!), and I've entered, assembled, and run the sample circle program from the assembler section of the manual, so most of the system (rack #232) is working (sound is still problematic but I can't believe that can be  relevant).

John

[John Stout]

By using the GUI interface I managed to get NIL<space> to print UAS (Unbound Atomic Symbol) and then NIL but nothing after that.

[John Stout]

Well of course, that was the clue. Finally ran the test.sh program again and some of the switches seem to have stopped working reliably. In particular the 400 (octal) switch used to set the length of the push down list.

So, back to breaking out the (de)soldering irons!

[John Stout]

After a morning's work taking the rack apart, resulting and, in one case, replacing a switch, then rebuilding the rack I've now got LISP working. 

In a way it's lucky that I tried LISP since it detected this problem. 

I took the opportunity to redo the foam over the speakers using double sided tape and sorted the heater on to the Pi for the power switch which I'll treat this morning. 

John