Projects

Digital Equipment Corporation PDP-11/34 - June 27, 2026

This PDP-11/34 (and its older brother, the PDP-11/35) was donated to me by the family of Melvin L. Cunningham. Getting it to Bogner Systems "headquarters" was a bit of a challenge though. The drive to get it was about a 12 hour round trip, covering close to 800 miles. When we got to the turnaround point, my friend Ryan and I dismantled the system and loaded it and all of the other hardware into the car in about 4 hours, and made the drive back. Upon returning, I unloaded all of the hardware (except for the rack, since that is the item I cannot move by myself) into my apartment. Another friend came over a couple of days later to help move the rack, and we got the 11/34 and RL01s installed in it. The process of bringing the system up went surprisingly smoothly- I dismantled the whole system, cleaning and inspecting as I went. I replaced a few smaller capacitors in the power supply modules, tested the larger capacitors, and reassembled the system, except for the cards. I fired up the system with an empty card cage, and the power supplies tested within spec (in fact, they were near perfect!). Once the PSUs had survived a good number of on/off cycles with no signs of giving up, I loaded the card cage with the CPU and memory, and gave it another power up. This time the front panel came to life, and the system was working! After doing some more tests, the rest of the cards were installed, and the console was alive over the serial port after executing from address 165020 (octal).

Since the initial bring up, the system has now had a Unibone installed (NPG jumper removed from the slot the Unibone was installed in), and the Unibone now runs as emulated RL02 drives, with UNIX V6, RSX11M, and a couple of other programs such as Snake and the Matrix screensaver. The system has two DZ-11 8 port serial cards installed, so the plan is to get UNIX V6 recompiled to use the DZ-11 ports, and allow people to login over a serial console server to experience early UNIX on a real PDP-11 serial terminal. Updated 08/26/2026