[vcf-midatlantic] A little personal milestone

David Gesswein djg at pdp8online.com
Sun Jun 18 20:25:55 EDT 2017


On Sun, Jun 18, 2017 at 04:35:05PM -0400, Evan Koblentz via vcf-midatlantic wrote:
> I have the instructions you made for entering the program (I will take a 
> fresh look at them to see if they make more sense to me now) but I'm 
> unclear about how to restart the program still in it from before.
> 
Set the address switches to 100 (octal) then hit load address switch then
start switch. Halt and single step switches must be off. I had start
address of 0 in the original write up. That will work for initial start up
but 100 is better for restart. 100 will work for initial startup also,

Before powering off the computer hit the halt switch to stop the program
running. If you turn off pdp-8 with it running it will corrupt memory.
I shouldn't do that but as the voltage falls the logic stops working
correctly before the low voltage circuit halts the processor.

FYI: There is one front panel light (memory bufffer 3) that is flaky. It may 
light when it shouldn't or flicker. 
> 
> >> Hopefully we can get it doing something more interesting
> in the fall.
> 
> Agreed! IIRC your advice was to run FOCAL through the teletype once we locate the misplaced connector card.

I think we also have to fix the teltype. I don't think it was working.

Focal is a resonable program to demo though there are other
reasonable programs. Just the * prompt probably won't
be that exciting so need to pick/write Focal program to run. 

We also have the plotter though I need to make an interface for it.
The PDP-8 has an A/D converter though currently disabled.

Probably we need to discuss at some point
more on the trade space of demo closer to historical usage of that machine / 
period usage / of sufficient interest to visitors. Doesn't have to be one
demo either though switching demos adds complications.





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