Paul Koning <Paul_Koning at Dell.com> wrote:
>>>>> >>>>>
"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...
Definitely.
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.
RSX uses the side effect of R0 being shown on the data bus on a WAIT
instruction as well.
And yes, I think you could get RSX running on an 11/05. I don't think
there was any PDP11 that couldn't run RSX, but it would be a rather
specific RSX you would gen for it. I doubt you could boot any generic
RSX system on that machine. Instead you would have to run the sysgen on
another machine, and just boot the resulting system on the 11/05.
Think unmapped RSX. That won't use any MMU. Still, you'd probably want
the full 56K on that machine.
Sufficiently old RT11s should work on that machine.
So would RSTS
V4A, if you can find an RK05 or RF11 or RP03 disk drive. :-)
New versions of RT-11 should do as well, as long as you select a variant
that don't need the MMU. Same goes for RSX, except that RSX won't be
self-hosting.
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.
And RSX is something similar. Fool around a little, set up R0, and WAIT.
The clock interrupt would break you out.
Johnny