Digital PDP 11/34a
PDP 11/34a
This is the oldest working computer in my collection, and in my opinion, the most impressive. This particular PDP came from a college where is was sold by Tektronix to run some test equipment. There are Tektronix serial numbers on the computer and the drives. There is also a Tektronix HP-IB interface card used to connect to the equipment.
Specifications
My PDP has the following cards installed:
- M8266 - 11/34a control module
- M8265 - 11/34a data paths module
- M8267 - 11/34a floating point processor
- M7859 - Console interface
- M9312 - Bootstrap terminator
- M7856 - DL11-W Serial and realtime clock
- M9202 - Unibus jumper
- 2x M7891 - 128KB / 64Kword Memory
- M7762 - RL11 RL01/RL02 Drive controller
- Tektronix interface card
- M9302 - Terminator
Currently I run the system with the RL11 controller removed and a Unibone in its place. The Unibone allows me to emulate drives so I can play with more operating systems. It also saves the RL01s from wear.
Drives
This PDP came with 2 RL01 removable pack disk drives. Each pack holds 5MB on a single platter. I only have the 2 disk packs, and RL01 packs are a lot more rare than RL02s, which is a big reason why I got the Unibone. The first disk pack was just XXDP+ diagnostics. The second was an install of Tektronix SPS Basic, a custom basic dialect made by tek based on Dartmouth basic. I uploaded an image of the disk here. You can boot this image in simh on an emulated 11/34a easily. Some manuals for Tek SPS basic here.
Power supply repair
When I received the system, one of the H7441 5v regulators was broken. With the help of some people on the VCFed forum, I was able to repair. Read the thread here.