PDP-11/05 returns to life
Paul_Koning at Dell.com
Tue Jan 6 15:31:38 CST 2009
>>>>> "Henk" == Henk Gooijen <henk.gooijen at hotmail.com> writes:
>> 2. Is there a chasing lights program I can run on the 11/05? Would
>> be nice to see it visibly doing something
Henk> Search the net. There is a small program (estimate 7 words). It
Henk> uses the RESET instruction (is that 000005?) ... not nice if
Henk> you connect an RX01 or RX02 to the machine as on every RESET
Henk> (INIT) the heads clunk!
That's a bit ugly...
A cleaner one is the RSTS null job. It relies on the fact that a
number of PDP-11s -- including the 11/05 as far as I remember -- will
display R0 in the lights during a WAIT instruction.
RT11 won't do, that uses the status register so you need a machine
that has it and that displays it. I forgot what RSX does. Not sure
you could run that on an -05 anyway.
Sufficiently old RT11s should work on that machine. So would RSTS
V4A, if you can find an RK05 or RF11 or RP03 disk drive. :-)
RSTS null job looks like this:
; THE SIMPLE NULL JOB
10$: MOV R2,R1 ;RELOAD THE WAIT COUNTER
20$: WAIT ;DISPLAY THE LIGHTS (R0) A WHILE
SOB R1,20$ ;KEEP WAITING
ROL R0 ;ELSE SHIFT PATTERN 1 PLACE LEFT
BR 10$ ; AND AROUND AGAIN...
You need a periodic interrupt, of course, to break out of the WAIT.
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