"There is a pdp11 emulator for ITS"

As seen on the PiDP-11 list:

Here’s a photo of a VT220 logged into ITS, with the pdp11 emulator running PDP-11 Logo.


where Lars Brinkhoff writes:

… I’d like to mention there is a pdp11 emulator for ITS. MIT had many PDP-11 machines offloading the main PDP-10 computers, and also standalone PDP-11 e.g. in the Logo group.

Bigger photo at the link. I’m supposing the ITS in question is running on a SIMH emulation - there isn’t yet a PiDP-10 although it is in the works.

(Wikipedia notes: “[The Incompatible Timesharing System] was written in assembly language, originally for the PDP-6 computer, but the majority of ITS development and use was on the later PDP-10”

Lars has also collected some photos relating to ITS.


@oscarv blogged about the upcoming PiDP-10 (which looks splendid) and comments about Lars’ ITS offering:

…more importantly, Lars has put tons of historical software on his ITS distribution. C, Lisp, Logo, the original emacs, all the old games - including the graphics masterpiece that is PDP-10 spacewar. Heck, the PDP-10 even runs PDP-8 and PDP-11 simulators.

But the ITS restoration effort did not stop at scraping off software and code from musty magnetic tapes around the world. Lars added the full hardware setup that grew up in MIT. Connected to the KA10 is a PDP-6 (so you can play spacewar without burdening Serious Users), a PDP-11 with the cool Knight TV terminals (so you can play spacewar burdening the Serious Users), an IMP networking interface, various graphical displays (a 340 on the PDP-10, a 340 on the PDP-6, a GT-40, and of course the Knight TVs. Plus a few Teletypes for maximum discomfort). It all runs out of Lars’ Github box - you find yourself the master of tonnes and tonnes of 1970s hardware. Phwoar.


Maybe of interest: @oscarv has set up a project page for the PiDP-10 on Hackaday, recently.

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We have ITS running on all available PDP-10 emulators: KLH10, Bob Supnik’s SIMH, and the newer SIMH additions by Rich Cornwell: the KA10 and KL10 processors. I think KA10 is the most fun because it has all the wacko hardware Oscar wrote about.

Feel free to visit me with telnet to its.pdp10.se, port 10003. A recent addition is a working, though early, version of the game Zork.


I will piggy-back onto this thread to post some great news.

Last year I read in the book The Tomorrow Makers that MIT professor Gerald Sussman had a 1967 listing of ITS in an office drawer. Naturally, I asked him if he still has it. Yesterday I heard from Sussman, and he confirmed he still has the listing which is ITS version 138. He also has a similar vintage copy of Maclisp version 97 and a corresponding compiler. I’m pursuing various options for having these listings scanned and made public.

So maybe soon we will have all four historical platforms running ITS: PDP-6, KA10, KL10, and KS10.


That’s excellent news! Please keep us updated with any progress, or point us at discussions and updates happening elsewhere!