PiDP-11 – Recreating PDP-11/70 with Raspberry Pi | Hacker News Reader

PiDP-11 – Recreating PDP-11/70 with Raspberry Pi

retroviator.com

116 pointstodsacerdoti52 comments

Similar in spirit, a recreation of the VAX-11/780: https://vxcompany.com/2016/02/13/a-working-vax-11780-revisit...

Where does one get that model?

I asked Wilm in Sep-2020 and three were produced as a one-off build, Wilm did not indicate any intention to produce more.

Now that you've got a PDP-11, you can run Empire on it!

https://github.com/DigitalMars/Empire-for-PDP-11

I purchased this as a kit and soldered together myself. It was a lot of fun to put together and it’s very illuminating to use. Happy to answer any questions about the kit or my experiences with it.

I have the PiDP-11, assembled it myself from the kit.

It was exciting for me to be able to run RSTS/E, which is one of the first operating systems I ever worked on. I only wish I had a Decwriter to physically connect to it.

And visitors to my office love the blinky lights.

I assembled an LSI-11 from bits from various university departments back in the late 80s with the intention of getting RSTS running, but struggled to find everything I needed (I was short of an RL01 I seem to remember). I had lots of fun though, and got RT-11 running from 8 inch disk.

The kit looks very cool, and would be significantly more convenient than the 19 inch racks I had before :) My how things have moved on (for the better).

If you want a DECwriter very $7K much, :) one of the photos in this current eBay listing looks like it might include one:

https://www.ebay.com/itm/Applicon-DEC-Digital-PDP-11-34-Main...

I got mine for $200.

And now I’m wondering what it’s worth on the open market. Biggest problem is it’s not something you could easily ship. It’s pretty heavy and not something you want tossed around.

If a couple people could lift it into the back of a normal $20 U-Haul van (maybe partially disassembled, if the legs come off), without injuring themselves, then the daytrip radius might cover a lot of geography of people who might want it.

(Otherwise, you've got professional crating, freight, lifts or docks, pallet jacks, insurance, etc.)

When I arranged for my university to donate an HP-PA box to the Linux kernel effort, one person made the trek to pick it up (and I vaguely recall they might've been relaying it to someone else). If a DECwriter needs a van rather than a trunk, it seems not that much different. Nostalgic vintage systems might be even more motivation for some enthusiasts to collaborate.

Tangentially related: I was thinking yesterday (when tempted to get a real VAX or Alpha VMS box, but not know what to do with it other than explore a while and then maybe put it up on the 'net for free accounts that would probably get abused)... What I'd really like to see happen is a very active in-person hands-on museum/clubhouse/afterschoolprogram/hackerspace for these systems. One half of your warehouse floorspace is a working setup of various of these systems, set up so that people can sit down and use them, terminal-server into them, etc. And the other half is where you hold classes/mentoring/workshop space for kids and adults who are already enthusiasts, as well as to introduce disadvantaged kids to the opportunity and catch them up on mentoring support in techie stuff that many kids have and we'd like everyone to have. I know there have been some places like that, and maybe there should be more, and refine the idea, and people will be happy to chip in to acquire pieces for the hands-on collection, like a DECwriter.

Well that's easy: http://chiclassiccomp.org/

I was once called by a former employer to see if I would do some consulting on a RSX-11M system I used to work on. When I realized I didn't even remember how to log on, I turned them down.

I have occasionally wondered if I truly forgot systems I once used, or if sitting down in front of one would reactivate all the old muscle memory. Assuming, of course, that subsequent sysadmins haven't changed it in the meantime:)

Or a DataSouth DS-180 dot-matrix printer!

Ebay and a serial USB adapter are you friends :).

Nope.

1. Decwriter terminals are very hard to come by! Haven't seen one on eBay in the years I've been searching. Look for yourself: https://www.ebay.com/sch/i.html?_from=R40&_nkw=decwriter&_sa...

2. Don't need a USB Serial Adapter with the PiDP-11. The PiDP-11 board will support up to 5 RS-232 ports on it: https://obsolescence.wixsite.com/obsolescence/pidp-11-connec...

I bought all the PDP-11 items listed on eBay around 15 years ago, so I was nodding in agreement. And yet: https://www.ebay.com/itm/Digital-DEC-PDP-11-05-with-RK05-dis...

I got a DecWriter on eBay for $200 and use the USB adapter. Works great.

Honestly, I've always thought a high quality 3D computer model of the entire thing (including the peripherals) would serve the purpose of learning about this stuff much better; an added benefit: doesn't take space. Learning in the virtual space in general has a huge potential. Even watching educational videos (like those found in abundance on YouTube) suffices in many cases. The age of plastic toys is behind us.

Typing stuff, interacting at a virtual terminal, sure.

But if you key in a bootloader via the toggle switches on the console, you quickly learn to think in octal (base-8).

If you live with the console blinkenlights for a while, you get a sense of roughly what the machine is doing as it winds its way through the code.

As with flight simulators, you can learn a great deal with virtual machines and simulators. But without tactile feedback, you won't quite understand how other people experienced these machines.

And much of the programming idioms arise from those experiences.

Hard, hard disagree. Nothing beats learning by getting your hands on a thing.

Agreed that hands on is always best, but virtual is great if you can lay hands on. PDPs are a bit hard to ship around.

Right? We're talking about the PiDP here, aren't we?

Hard disagree with your disagree.

A detailed 3D model could make it possible to zoom down to the gate level and show states propagating as the processor works - optionally with timed animations showing actual physical propagation, as opposed to an idealised logical model.

And then up to module and board level. And so on.

It would be hugely more informative than a physical panel of blinkenlights and switches.

VR can help with that. Not with all things as haptic feedback is not not ready yet. But there are people already making gloves with feedback for 50 dollars or so.

Interestingly, the author gives four reasons for building the project. Four “purposes” if you will. Learning was not one of them.

Supposedly a PDP-10 (KA10) is on its way too. Although there hasn't been an update for a year or so.

http://obsolescenceguaranteed.blogspot.com/2020/02/inevitaby...

Now I would love to try TOPS-20 on it along fdrotz :p.

I, for one, appreciate these efforts to not only preserve history, but to make it available to new generations. There's so much that can be learned from these historical machines, and the look and feel is part of that :)

I connected an old DecWriter III/LA120 to a Raspberry Pi PDP-11 and noe really have nostalgia locked down. Wide green bar paper terminal connected to a 70’s computer.

Nova 1200 would be easier. Just glass panel painted mostly black and regular off-the-shelf switches. Bigger problem is the menacing glow of blinkenlichts. Leds will never do.

If the PiDP11 follows Oscar's PiDP8 then the blinkenlights are pulse-width-modulated and you do get a warm glow out of them rather than a heartless and cold on/off. My recollection is that more of the PI's cpu cycles are spent doing this than are spent emulating the PDP8 (and, I'm guessing, the PDP11).

Indeed, this era of machine retained a sort of “electromechanical” feel that the incandescent bulbs contribute to. Not to mention the DECwriter that was usually attached to it.

DECwriter would have been a luxury. ASR-33.

There is a kit for an Altair replica which uses simpler switches. https://adwaterandstir.com/altair/

With this or a PiDP-8, I've idly thought about learning enough to write a "terminal operating system" so one could plug it into a USB port and get a shell to a Linux or BSD system. That way it could be of actual use to the owner after playing with older operating systems loses its allure.

That sounds really interesting!

I love my PiDP-11 and the PiDP-8 as well. He is working on a PDP-10 next. That is going to be hecka fun to be running TOPS20 (yeah I know simh dude, but it seems so much more fun when you have the "look" to go with it.)

TOPS-20 with a KA10 console. Anachronistic but fun!

Great. I can see a whole new market for these kind of retro machines. As I never used a PDP-11, this however doesn't have the same kind of nostalgia for me. Is anybody doing anything like this for IBM mainframes?

For those with nostalgia for Wargames, there's a nice IMSAI replica in the same vein:

https://thehighnibble.com/imsai8080/

Bought one of these about two years ago. Did some of the assembly, but it's still not done.

Looking forward to playing "Super Star Trek" on it.

What a great accompaniment this would be to reading Steven Levy’s book Hackers - The Hero’s of the Computer Revolution.

https://en.m.wikipedia.org/wiki/Hackers:_Heroes_of_the_Compu...

In that case you should probably try ITS.

http://github.com/PDP-10/its

Thanks for the link.

What hardware this would install on?

I was just thinking how neat it would be to have a place where you could go online to try out all these old operating systems.

It works on a PC or Rasberry Pi, or anything similar. Linux works best, because that's what most users have, but MacOS, FreeBSD and Windows work too although the last one can't run the build script.

Various people have ITS running online. Here's mine (click to access the hidden content). http://its.pdp10.se/

Thanks I checked it out, looks cool though I couldn’t do much cause I’m on a mobile device and the keyboard never popped up no matter where I tapped the screen.

These emulator setups always seem super complicated to me. From one of the pages:

“This is a Knight TV console emulator. It's connected to a PDP-11 emulator running the TV-11 software, which in turn talks to a PDP-10 emulator running ITS.”

Wow...that’s quite a long chain of software cobbled together!

This is awesome! I'm definitely looking at getting one of these kits!

Oh, those marketing folk who designed the console switches -- how often I dreamed of appropriate places to send them for education...

What was wrong with them?

The sexy plastic switches on the PDP-11 console panel are not easy to toggle, to operate from the bottom or the top of the switch.

When you are flipping through a few hundred words of bootloader or debugger, I was way faster on simple, metal toggle switches.

I will try to find a better example, there are a number of these demonstrations on YouTube:

https://youtu.be/qv5b1Xowxdk

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