50 years of PDP-8/E! Happy Birthday!

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Volker Herrmann

Aug 13, 2020, 2:50:01 AM8/13/20
The PDP-8/E was introduced 1970 August 25.-28. at the Western Electronic Show And Convention Los Angeles (WESCON).

To celebrate this I made a short clip:


If you like to read some words from Remo Vogelsang, the leader of the PDP-8/E development team, you maybe have a look here (in German language)

Have fun and keep the old iron running!



Aug 13, 2020, 4:45:22 PM8/13/20
love the video! (sadly my PiDP8 replica can't quite manage to blow out any candles :-))


William Cattey

Aug 14, 2020, 5:16:23 PM8/14/20
And we have yet to plumb the necessary bit set/clear stuff through SIMH to get MUSIC.SV working.

Thomas Moss

Aug 16, 2020, 8:50:01 PM8/16/20
On Wed, 12 Aug 2020, Volker Herrmann wrote:

> Date: Wed, 12 Aug 2020 23:50:00 -0700 (PDT)
> From: Volker Herrmann <vher...@me.com>
> Newsgroups: alt.sys.pdp8
> Subject: 50 years of PDP-8/E! Happy Birthday!
Great stuff! The part with the candles gave me a good laugh :)
I might have to try this myself too...


SDF Public Access UNIX System - https://sdf.org

Martin Eberhard

Sep 2, 2020, 11:22:15 PM9/2/20
Just saw this thread, and realized I got OS/8 running right for the first time (in decades) on my PDP-8/e on August 25, 2020 - an auspicious day!
Took me almost 2 years to get to this point, from a pile of dirty, broken parts. So far, it seems to run great. Passes every MAINDEC program I can find, seems rock-solid so far.
KM8-E Memory Extension
32K of core (4X MM8-EJ)
TD8-E with TU56
MR8-E boot ROM for the TD8-E
KL8-E (M865) serial port as the primary console (110 baud only)
Teletype ASR33 as the primary console
KL8-JA modified for 38,400 baud (set up for file transfers)
KL8-E (M8650) modified for 9600 baud (set up as an alternate console)
KP8-E Power-fail - autostart

Maybe some floppy disks next (-:

Volker Herrmann

Sep 3, 2020, 3:05:01 AM9/3/20
Yes a great date for the rebirth.
Do you really need 32k? It takes a lot of current and that is hard for the old powersupply.

Martin Eberhard

Sep 3, 2020, 12:31:56 PM9/3/20
> Do you really need 32k? It takes a lot of current and that is hard for the old powersupply.

(-: "need" is a funny word when working with these old machines! But I went through my power supply pretty thoroughly, and it seems to be up for the job - especially since my PDP-8/e spends most of the time "off". I also installed an air filter on the left side of the PDP-8/e, to clean the air that's being pulled into the machine. It is surprising how much dirt the filter collects! Should help keep the power supply healthy.

I've got my OS/8 set up so that it sees only 7 fields, with the 8th field (field #7) occupied with my own MEMON-8 monitor program - along with the TD8-E boot ROM. MEMON-8 is a stand-alone program that lets me poke around in memory, and read and modify DECtapes on a tape block basis. MEMON-8 also allows me to transfer whole tape images onto and off of DECtape, using the Xmodem protocol (which provides flow control without additional software on the PC end). I used MEMON-8 to load images of the DEC OS/8 distribution tapes from pdp8.net (in .TU56 format) onto reformatted DECtapes. I also use it to create .TU56 tape images of my own tapes as backups. (MEMON-8 code and user's manual is here: https://tinyurl.com/uvg2lwq)

Speaking of power supplies, the power supply in my TU56 failed recently - one of those 6-terminal bridge rectifiers died. I replaced it with a more conventional 4-terminal bridge (massively overrated because that is what I had), and the tape drive works fine again. But I'd love to find a correct replacement for that bridge. The dead one is a Solitron G797. Does anyone have any idea where to find such as thing? I know they are terribly obsolete...

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