|d|i|g|i|t|a|l| pdp11

Woodstock's PDP-11

Shortly before I started studying at the University of Karlsruhe in 2000, I heard rumors about a PDP-11 that was said to still be in the basement of one of the university buildings. As I had wanted to see such an old beast since I knew that they existed, I asked everybody I met there, hoping somebody would know something about it. Someone told me about a PDP-9 that had been thrown out just half a year before, or they told me about a HP1000 and some HP Fourier Analyzer they once had, but nobody seemed to know anything about the -11. Until in March 2001 I asked the right guy, someone working at an institute where I was taking courses.

Soon after I met him he agreed to show me their machine room. Even before entering the machine room itself, I couldn't quite believe what I saw down there in the basement. They got a 11/20 there, with the cover of its mounting box replaced with glass so you could take a look inside, they got ASR33 Teletypes, walls of documentation, boxes full of paper tapes and punch cards, in short, all kinds of strange old stuff which I had never seen before. In the machine room itself there was a VAX 8600, countless small white DEC racks containing a VAX 8300 and lots of peripherals, countless MicroVAXen and VAXstations, DECstations, Alphas, Suns and other small boxen, and finally, the last large -11 they still had. I was told that back in 1988, there were PDP-11 racks on every wall down there, and that they used them to teach students how to toggle in small programs using the front panel. I wish I could have seen this myself.

When we left, he told me that all this stuff was about to be thrown out, since the university needed this room. He told me whom I had to ask if I wanted to have some of this stuff, and for the following three months I besieged this other guys office. This guy, being the sysadmin there for the last twenty years or such, went down to the machine room with me every now and then to move some of the stuff to a small unused room. I took all MicroVAXen, VAXstations, DECstations, terminals, cabling and documentation that I could possibly stuff in my small appartement, and even some more. In June 2001 I rented a small van, and with the help of two fellows I took most of the stuff home. Getting more than half a ton of old iron three stairs up was harder than I imagined.

At first I didn't intend to take the -11, since it was way too big and too heavy. But when they told me that it'll be trashed, I moved it into the small room, too. I didn't want to see it being trashed, so I tried to find some place to put that big machine. The Chaos Computer Club was interested in the VAX 8600, they wanted a big VAX for their 20th anniversary, and the 11/20 was supposed to be placed in the museum that the computer science folks at the university had. But this didn't happen, some guy trading old DEC stuff and having a museum somewhere took everything I didn't take. This saved the university the cost for trashing the less interesting stuff.

I couldn't find a place for the big -11 until March 2002, and the university wanted me to move it out since they didn't want it to stay there forever. A friend of mine, living near my hometown 500 kilometers away from Karlsruhe, offered me to put it in the basement of his house. He borrowed a trailer from a friend who used it to transport cars, hooked it up to his pick-up truck and drove down to Karlsruhe. He didn't believe what I told him about the size of this stuff, but with some help from another friend we managed to move all the -11 stuff in the trailer and immediately carried it home. The basement where we wanted to put the machine was still full of other stuff, it took quite a while to make room there. But the hardest part was yet to come: we had to move the -11 downstairs, without being able to take everything apart. Especially the rack containing the tape drive, weighing some quarter ton or such, had to be moved down in one piece. Once we got everything down in the basement, we noticed that the door to the room intended for that stuff was about 5mm too low.

We finally got it in there, and it will for sure stay there forever. After moving it in, a friend took these pictures while we were looking through the documentation, disk cartridges and magtapes we got with the machine. It took up to July of 2003 to make the -11 work at least partly, and it is still much work needed to make it fully functional again. The pictures on this site were taken immediately after it booted from some RSX-11M 3.0 tape for the first time in about 15 to 20 years.

three H960 racks

The left one of the H960 racks you can see above contains a PDP-11/34A and its smaller peripherals:

The mid H960 rack contains a TS11 tape drive in the top half which is connected to the PDP-11/34A, and one very large, currently unused unibus extender containing some flip-chip modules, a DMR11+DMP11 and some strange 3rd party controller in the bottom half.

The right H960 rack contains only two BA11-L, one containing a PDP-11/24 and the other one being a small unibus extender, and two System Industries controllers (9400 and 9900), which are currently unused.

There is also a H9644 rack currently containing some OEM LSI-11/23 CPU box which I later got from a friend, a BA23 containing a MicroVAX-II that was a VAXstation-I when I got it, and two Fujitsu SMD drives connected to the VAX. In the lower part of this rack is some very large rack fan system.

There is another small white rack containing a spare RL01 that came along with the LSI-11/23 and a Fujitsu M2284 SMD disk drive which I believe to contain an RSX-11M+ installation that was once used with the PDP-11/24.

If you want to, you can access all pictures of this page here. There are also some pictures that were taken by a friend when this stuff was still sitting in the small unused room at the university.


Valid HTML 3.2! Kampagne für sauberes HTML, welches in jedem Browser dargestellt werden ka