DEC PDP-11/70 - NPL Scrapbook - restoration and machine tour | 1970's computer

A team of volunteers have been working to restore a PDP-11/70 for the past five years. This machine came from the National Physical Laboratory (NPL) in the UK, and ran a system called "Scrapbook". This was used for storing information, word processing and electronic communication. It also featured hyperlinks, which later came to be used in the World Wide Web.
The machine is now up and running, and work is progressing to repair a second RM03 disk drive. Once that has been done, it is hoped to mount the original Scrapbook disks.
Sean Allison takes you on a tour of the PDP-11/70, powers up the machine and loads some diagnostic tools. The restoration team then discuss the technology used in the PDP-11/70, and challenges faced getting the machine running.
Chapters:
00:00 Machine Tour
02:29 Powering up and booting the operating system
07:30 Running test programs
09:09 Meet the restoration team - interviews
Recorded February 2022.

[@baxtermullins1842]

My lab had over 30 PDP 11/xx including 45, 60, 70 & 80’s. The disks had 5 platters holding the RS11M OS and my designed OS. They were used in groups of 3 to 5 integrated computers with all connected through busses! Amazing machines. The front panel was octal, but internally it was hexadecimal!

[@billreyna1355]

Bring back memories of my DEC field service days. These mid-systems were everywhere and thus my service calls were anywhere. What a way to make a paycheck.

[@JonMotivationalRend]

Those engineers earned a shed load. Especially with all the Pms.

[@haroldswaffield1449]

I loved that version of the 11/70. From manufacturing to field service. The look was sleek. I always had a penchant for Dec blue as well. Wonderful restoration work guys.

[@tnmoc]

Thanks Harold!

[@mihalachebogdan1]

Wow as a young computer lover this is just impressive . I love it , one can't imagine it till one sees it. Thank you very much for providing this visual representation and of course for your restoration . Incredible !

[@ycryoon]

I studied PDP computer at DEC training center in Boston in 1989. I was a repair technician and my company had PDP series and VAX series company.

[@misterguts]

I never worked with a PDP-11, but did work with a Data General Eclispe S/130, which I think is in the same class. I still dream about the work I did over 40 years ago. Sean, the likes of us are on the way out, eyes and all... But I think we may have had the best of it.

[@nakfan]

Thanks for sharing… What a great project … and video 👍 All the best from Denmark, Per

[@cjh0751]

Fantastic work by some very dedicated individuals. Well done

[@sfperalta]

Back in 1980 I worked as a computer repair technician and a lot of our customers ran PDP 11/34 and 11/70 systems. Once had to troubleshoot an 11/70 at a Navy facility in San Diego and spent 3 days isolating a stuck address bit which turned out to be a backplane wire wrap connection gone bad. These machines were monsters, but it was state of the art back then. I think my iPhone has way more processing power LOL, but the Massbus architecture of the 11/70 allowed it to support a ton of peripherals - disks, tapes, terminals - so you could support a medium size organization with the one CPU. Ah, heady stuff!

[@pereimar]

Brilliant work! I didn't get to see these machines running live, but I'm really fascinated by them due to the influence of Unix (FreeBSD/Linux). Every time I go deeper into my research, I learn a lot from these technologies that are the basis of everything we use today! Congratulations on the excellent work of preservation and restoration! Best Regards, Marcos Pereira Rio de Janeiro, Brazil

[@lumpyfishgravy]

Good sound, appreciated.

[@jerryeckert106]

Great work, guys! It is nice to see the PDP-11 and RSTS running. The first computer I used was a PDP-11/20 in 1973, then a PDP-11/50 for several years. For nostalgia's sake, it would be nice if you could get a DECtape unit (TU55 or TU56) and a paper tape reader/punch (PC05).

[@rjpmcmillan]

I used to service these computers in the early 80's and had a lot of fun doing it. Give me a PDP over a PC any day :-)

[@russellfinch5493]

Your tape drive was a TK-90 I believe and was manufactured in Springfield, Mass before 1993. Probably between 90-93. In 93 as part as the big sell off, the Springfield facility was shut down. They produced all the tape drives, TE16, TU77-78 for DEC and also produced the first solid state HD, ESE20 as well as other smaller HD's. They had the largest clean room east of the Mississippi in the early 90's. I know, because I worked there and was outsourced in 1993 after 16 years with the company. We got to play around a lot with equipment and I had a system running RSTS of 100 users on a PDP 11/34 with 100k of memory. Yes, that is 100k of memory. Of course, no graphics but still 100k to run the OS. Had 3 RK05's to boot from. Later, moved up to a micro VAX that by then supported 16 bit graphics. Woo-hoo. That was amazing. Brings back a lot of memories.

[@apogeedata]

Thank you for the trip down memory lane

[@judmcc]

I love those rocker switches!

[@andrewjenery1783]

Reminds me of a firm called ADS based in Oxford St, London in the mid-80s that had one of these. They ran computer training courses and used their own version of COBOL for writing programs for various commercial applications.

[@thudtheace]

When I was a kid in the 70's and 80's our school had a PDP-11 to handle their office applications. I remember seeing it when waiting to go to the principals office for some kind of grade school shenanigan's. Many many decades later I worked with MicroVAXs' that served as controllers on a particle accelerator. In fact the custom Q-bus cards from a PDP-11 were moved to a microVAX(sadly I don't remember the model numbers) while I was there. Cheers!

[@gort59]

Love these big iron machines!

[@navyspook79]

I love these old PDP machines. When I was in the Navy, we had PDP1170 that ran message processing applications. It ran using RSX11. Amazing machines of their time. Loved working with them. Required more hands on.

[@ImayonRaja]

Absolutely brilliant Sean!

[@CoverMechanic]

such a well made video, you’re doing a fantastic job of these

[@willbarnes6602]

Programmed the PDP 11 at a bank in Dallas. Lovely. I loved the PDP 11 interface. Never liked the IBM 370 JCL.

[@mikesmith3704]

Great job guys, took me back to Barclay Road and Millshaw Park :-)

[@glamill51]

Mike - good to see that you are still with us. Barclay Road - I just fixed H7xx power supplies & Drico printers - you gave me no-end of help there. Fish 'n chips in overtime. Millshaw Park was the start of my computer career - MK3 vdu, SMD drives, 11/70, 11/44 (after a course with DEC in Reading), VAX 11/780 to start with . Then to the Glass Palace. I have you, Brian Lindley and others on my SYSTIME dvd! Great memories.

[@billb6283]

We had CDC 9766 300MB removable disk drives attached to our PDP-11/70.

[@malcolmgibson6288]

PDP11 was my introduction to computing at college.

[@NCGPUSA]

Great job, so many memories

[@nickblackburn1903]

Absolutely amazing thank you everyone and well done keeping this lovely computer going. I bet there is a lot of Tea drunk whilst fettling this beast. I am so jealous, I would love to work at the NMOC but I live on the Isle of Man. Ah well I will visit again soon and look forward to seeing this in operation. Thanks :)

[@arf20]

I need to see Unix V7 running there

[@JKivlighan]

Supported PDP 11/70 systems in San Francisco from 1975-1979 and then in Silicon Valley from 1981-1985.

[@mikeclarke3005]

WOW much newer version, the PDP 11/70's worked on when in teh Aerospace field was black/Purple and Disk drives big a washing machines

[@FunkmeisterOfSedgley]

We used RSX11M+ on our PDP's at Land Rover.

[@edgeeffect]

We had an 11/23 and an 11/73 with RSTS 90 at college.... but neither of ours had a hardware front-panel.... just before I started college, they got rid of their Data General Nova which was bedecked by blinkenlichts... I feel I was cheated. :( ;) Oh, incidentally I can be so sure of the RSTS version, 'cus I've got a printout to hand on my desk. ?????????? That VT-320 is way to modern to be authentic ;) Needs a nice VT-100.

[@seanallison]

VT100 would be nice! We have a few VT320s in the museum but not so many VT100s but when the system goes on display we will as you suggest probably provide it with a nice VT100

[@stephenwalters9891]

This machine belonged to a computer called NETREACH that stored it on HMS-PRESIDENT (1918) and I used to be a member, back in the 1990's

[@JonMotivationalRend]

.I used to be a pdp 11/70 operator. Remember backing up the wrong way. Wiped out a companies entire days work. Remember performing many Sysgens.

[@rhonda-my_honda_cb500x3]

Y'all have heard of 'write-protected' storage. Well, a 'head crash' gives you *read*- protected storage on those platters 🤕 I wonder if there was DEC equivalent of 'Norton Utilities' back then to mitigate those situations to *try* and rescue whatever remained on the platters. 3600rpm = 60rps which equates to a 'degree' sector read latency of 16.67ms if my maths & thinking is correct.

[@seanallison]

Unfortunately in this instance it was the servo head that crashed. It was a scratch disk in any case so had no data of value on there. In the field in the 1980s there were no such utilities to help rescue data. With some drives (RL02, Ampex etc), we simply had to clean the head and disk platter the best we could and hope the heads survived long enough to get a copy! No such luck with an RM03 though as they were much more critical - once a head crashed, the pack was condemned. The holy grail we are looking for is an RM03 alignment pack, of which there appear to be zero left in the world! I would be VERY happy to be proved wrong :-)

[@doronweiss1192]

Really cool. What is the clock frequency of the CPU?

[@tnmoc]

We'll try and get one of the team to answer your question.

[@seanallison]

Hi Doron - it runs at around 5MHz

[@wonderboy7768]

13:49 Robert Plant!

[@sjzara]

It would have been nice to see a close up of the screen.

[@seanallison]

Will see what we can do the next time we are down there Steve

[@danielthomas3057]

RSTS resource sharing time sharing, if memory serves.

[@JonMotivationalRend]

Rsts/e

[@captmulch1]

Macquarie University Fortran 77 Computing 101 PDP11 1984 …

[@lboston4660]

@0:37 pci express x100

[@NicFerrier]

No offence but all you guys are "of an age" (as am I) What do we do when you (and I) are not here anymore? Do these things just go away then? That would be a shame, right? We'd like to enable historians way into the future to maintain these things. It seems like the next generation might be the absolute hardest? Are there 20 year olds interested in working on this stuff?