I Bought the HEAVIEST Computer on eBay: The PDP-11/34!

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Twitter: @davepl1968davepl1968

[Remowylliams]

It's scary to remember so many operational facts about these computers. In the early 80's I got hired by a 3rd party DEC service provider as a bench technician fixing VT-100 terminals. After fixing all the broken terminals on hand. I turned to work on our 11/40 test bench machine which had been down for nearly a year prior to my arrival. I taught myself how to repair and operate the machine and in 9 months became the company's senior field technician. As long as I had test equipment, schematics and coffee I fixed most everything I was thrown at. Floppy Drives, Hard Drives, Tape Drives, serial controllers, line printers, power supplies. These machines had modular switching power supplies that would fail pretty frequently. I built electronic dummy loads that dissipated power through 2N3055's strapped to massive heatsinks with fans blowing on them. It was a great time working with these work horses. Thanks for the memories. I'll watch any PDP-11 video you put up. Cheers.

[waslucena]

In the 2000s, the Rio de Janeiro metro was still running on PDP-11 systems. There were five PDP-11s for ticketing and four for the automatic pilot system. In ticketing, one PDP-11 acted as a supervisor, selecting which of the two controllers for the turnstiles would be the master and which would be the slave. The other two PDP-11s, along with four tape units, recorded the data from each ticket passage. Each PDP-11s had 96K words of memory.

Motorola developed a specific serial communication chip to connect the central system to each entry turnstile, as the distance was over 30 km/18 mi. The PDP-11s for the automatic pilot system allowed for acceleration and braking at stations without human interference.

Access at the turnstiles was through magnetic stripe cards. The turnstile would read the card and send the data to the PDP-11s, where the cards were validated. If they were multi-trip cards, one trip would be deducted. If the card's trip credit was exhausted, the PDP would instruct the turnstile to retain the card. Otherwise, the PDP would send a command to rewrite the card with the trip deducted.

The project was developed by the French company Alstom in the 1970s, and the metro was inaugurated in 1979.


It's incredible to think that all this was still running in 2000, and the cost of a technological upgrade involving the replacement of all the turnstiles and PDPs was not deemed worthwhile.

[postiemania]

50 year old Computer and there is an expert on the net to help you fix

[ethandicks]

Glad I've been able to help. The PDP-11 is a fantastic machine and it's great to see (another) one come back to life.

[waaos]

PLEASE more DEC ANYTHING. I was with DEC for years from PDP 8 series through most of the VAX series. I know these systems frail to most simple systems now in some ways but the evolution of DEC over the years was amazing. I am happy and honored to have been part of the excitement.
In case you may be interested Ken Olsen did everything to keep the payroll running even when times were tough and we did have some lean times. He made some errors in judgement by not getting in the PC biz earlier but there were no crystal balls then and as they say, it is what is or was, as the case may be.
Thanks for keeping some of the DEC gear going and preserving the tech on your super neat YouyTube channel !!!

[jaimeduncan]

The fact that one can run a full PDP-11 emulation on a Raspberry pi is such a flex of the microelectronics and computer industry (the software that allows to laying billions of transistors and perform optimization of the wire layers). Congratulations on your new BB

[dmacpher]

Sort by “heaviest” is really an under appreciated feature

[wizardpb]

In Sept 1978 I started a PhD - the day I started, my supervisor showed me into a newly constructed computer room, false floor and all, and showed me a brand new PDP 11/34. He handed me a 9-track tape, and a single piece of paper. He said: "This is Unix Version 6 - please get it running on this machine". On the piece of paper: the tape deck bootstrap, all in octal.... 46 years later, I'm now retired. Ah. memories....

[mushroomsamba]

When you need an engine hoist to move your computer you know you've made it.

[SpeZi-trgr]

Vintage computer and a muscle car in the garage. Guy's livin' my dream. Well done sir, well done!

[bongolian]

I really enjoy the way you narrate. You're refreshingly emotionally neutral, concise and comprehensive. Thank you for a great and informative video!

[MarkoVukovic]

This is such a privilege to see someone like you make these vintage machines work. Can't wait to see what you do with it! Thanks for the great content!

[captainsunshine]

This morning I didn't know what a PDP was. This afternoon I'm a fan and tomorrow I'm going to need more videos on it!

[berylg]

What a treat to watch! I started laughing when you realized that you would need to make a modification to the wire wrap bed. Back in the 1970s we had what were called (in those dark days) "wire wrap girls." I would go out to a customer site (such as Lawerence Livermore Labs or a petroleum refinery) and see that a system needed to be brought up to current mod status. The call would go out for one of the "girls" who were older and more precious to the company than me and they would pull out a worksheet and a wire wrap gun and we would go get coffee.

[morganskinner]

I first used a PDP-11 in college at 17 ish, that would have been 1984. I wrote a Z80 emulator on it for my final year project (I was a confirmed Sinclair fanatic). There was a much larger PDP-11 (70 I think) at Polytechnic, and then I moved on to VAX’es when I started work in 1989. They were superb machines, and I fondly remember them. Manuals! Real, proper manuals that told you everything. Being a true geek I learned VAX Macro assembler and wrote a modem driver in it - this was used to communicate between remote sites in the UK. I think my finest hour was patching an RMS database that was corrupt for a water company in Eastbourne. All in all, I loved it.

And I retire today!

Now it’s pet projects that will keep me busy, I can’t wait! Thanks for the content Dave, you never cease to be inspiring and interesting.

[bobbyb]

PDP 11 best system ever made. All us dec folks appreciate you getting it running.

[hessex]

When I was in college the PDP-11/45 that we got out of the trash at Bell Labs (I realize this is a lot to unpack, also we totally didn't Redbox the call to Bell Labs to arrange for the pickup) we disassembled everything and moved it all piece by piece. This was much easier, it also helped to have a house full of college students. I am really happy that you got a big PDP. It brings back memories for me. We ran RT-11 on ours.

[bigbadwolf]

Excellent, most excellent.
There can never be too much coverage of DEC hardware.

[lorensims]

Fun!
I really appreciated that photo of the PDP-1.
I read where the guys at MIT, when they got their new PDP realized it had a "scope, " so they wanted to create a program to demo the capabilities of that scope. They created the very first video game, Space War, using model train controllers as game controllers. I've previously seen only black and white photos of that model.
I first learned Microsoft BASIC on an Ohio Scientific minicomputer that our tech school had in a back room.
For seven years I was the operator for a series of IBM System/34 and System/38 minicomputers. For five years after that I was the lead operator of an IBM AS/400 Model 70 supermini shop.
We were trying to demonstrate we didn't need no steenkin' mainframes. But we were pushing those machines hard.
The guy from IBM said we were considered to be "hot-rodders."
I would love to see you boot up UNIX on your "new" machine. They invented C to enable them to port UNIX to different computer architectures.

[dennisjorgensen]

DECee:badge:19220. I was an instructor in the mid-70s on the KL-10 (DecSystem10) and 11/40 teaching techs how it worked and how to repair. The Large Computer Group was based in Marlborough MA. One Ken Olson story from that era. He was famously “frugal”. He drove the cheapest Ford Pinto. One day he was visiting the production floor. One of the techs anticipated his walking by and super-glued a quarter just off the walking path. Sure enough, Ken couldn’t help himself. A legend was born!