PDP-11/05 returns to life

[Paul Koning]

>>>>> "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.

    paul