PDP-8 Straight 8 restoration

Nigel Johnson nw.johnson at ieee.org
Sun Mar 29 16:59:42 CDT 2020

Brings back memories!  My first 6800 cross assembler came to me as 2000 
Fortran source code punch cards. We had an F4R4 compiler on the PDP11 
but the card reader was on the PDP-8.

The only common peripheral was paper tape.  One night, the Chief 
Engineer and I fed the cards into the PDP8 card reader, punched tape, 
and fed it directly into the PDP11 tape reader.  X-on X-off was handled 
by hitting the stop and continue buttons on the PDP8 as the punch was 
faster than the reader.  The buffer was a pile of paper tape in the 
floor, which we carefully prevented from tangling.  Somehow OS/8 managed 
to not crash with the constant start/stop.

Nobody was more surprised than we were when the output compiled 
perfectly on the PDP11 and we made our first 6800 program - a ham 
repeater controller!

The Chief Engineer is still alive - I was at his 95th birthday last year 
and we often have fun talking about the good old days!


Nigel Johnson

On 29/03/2020 16:59, Diane Bruce via cctalk wrote:
> On Mon, Mar 30, 2020 at 09:47:51AM +1300, Brendan McNeill via cctech wrote:
>> Here in NZ and around the world many of us are in lockdown and spending more time on our computers, if that were possible.  I have just completed the restoration of a PDP-8 Straight 8 which I believe is the only one in New Zealand.  You can view the restoration story and find appropriate resources here:  https://pdp-8.nz <https://pdp-8.nz/>
>> While it plays Chess, it would be great if someone wanted to write (say) a Prime Number Generator, or some other application and email it to me off list.  I have Focal-69 and can probably source other languages for this wonderful old machine with 4K of memory.
> I have memories of keying in RIM and BIN. Long long time ago. I also learned
> how to talk to the OS/8 file system so we could play morse code from a file
> instead of a paper tape for our University club station. ;)
>> --------------//----------------
>> brendan at mcneill.co.nz
>> +64 21 881 883
> 73 de VA3DB for those that care ;)


Nigel Johnson

Amateur Radio, the origin of the open-source concept!

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