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PDP-10
its
Assembly2017–2026
PDP-10 / its

its

Incompatible Timesharing System

23Distinct people
76Mentions
0Explicit recommenders
963GitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Incompatible Timesharing System

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

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No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 8:03:49 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year76 dated mentions

Observed mentions: 2017-01-24 01:14:25 UTC to 2026-09-12 02:00:03 UTC.

051015202017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 2 mentions; 1 submissions, 1 comments20172018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 6 mentions; 0 submissions, 6 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 6 mentions; 1 submissions, 5 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 9 mentions; 0 submissions, 9 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 8 mentions; 1 submissions, 7 comments20212022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 7 mentions; 1 submissions, 6 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 19 mentions; 2 submissions, 17 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 11 mentions; 2 submissions, 9 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 5 mentions; 1 submissions, 4 comments2026-01-01 00:00:00 UTC to 2027-01-01 00:00:00 UTC (exclusive): 3 mentions; 0 submissions, 3 comments. Incomplete calendar period.2026*

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC211
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC606
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC615
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC909
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC817
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC716
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC19217
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC1129
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC514
2026 (partial)2026-01-01 00:00:00 UTC2027-01-01 00:00:00 UTC303

From the project README

An excerpt from the repository, fetched Nov 13, 2026.

Read the project’s introduction
Incompatible Timesharing System About ITS ITS, the Incompatible Timesharing System, is an operating system for the PDP-10 computer family. It was created by hackers at MIT in the 1960s. The MIT site was shut down in 1990, but enthusiasts continue to operate ITS systems to this day. Some notable ITS features: Hosted the first versions of Emacs, Zork, Macsyma, Maclisp, Scheme, and multi-player Maze War Virtual memory User-space device drivers Networking: TCP/IP, ARPAnet, Chaosnet Transparent network file system Terminal-independent text output Graphical workstations There is a mailing list for discussion about ITS. Go to http://its.victor.se/mailman/listinfo/its-hackers_its.victor.se for more information. About this project This repository contains source code, tools, and scripts to build an ITS system from scratch. The goals are: To provide an automated build from start to end. No user intervention is necessary. To check which programs have source code, and which programs are missing source code. To ensure that we know how to build all programs. To update programs with the latest bug fixes and enhancements. To be able to set configurable options across the whole system, such as host name, IP address, hardware devices. The build currently runs on the SIMH and KLH10 emulators. Of course, we'd be delighted to test this on a real KS10. Building To build ITS with this repository, you need some tools installed; see the table below. Ensure all submodules are checked out, and then type make EMULATOR=simh, make EMULATOR=pdp10-ka, make EMULATOR=pdp10-kl, make EMULATOR=pdp10-ks, or make EMULATOR=klh10. This will leave built files in the out directory, some of which are disk images with ITS installed. Emulator Dependencies klh10 git, c compiler, make, expect, curses, autoconf simh git, c compiler, make, expect, curses, autoconf, sdl2 pdp10-ka git, c compiler, make, expect, curses, autoconf, sdl2, sdl2-image, sdl2-net, gtk3 pdp10-kl git, c compiler, make, expect, curses, autoconf, sdl2, sdl2-image, gtk3 pdp10-ks git, c compiler, make, expect, curses, autoconf, sdl2 Usage To start ITS, type ./start. If you see KLH10#, type go and Enter. If you see the DSKDMP prompt, type its, press Enter, and then ESCG. If you use the pdp10-kl emulator there is no prompt and you need to type ESCL ITS, press Enter, and then ESCG. Eventually, you will see SYSTEM JOB USING THIS CONSOLE. You are now ready to log in, so type CTRLZ. See doc/DDT.md for a list of useful commands. Alternatively to logging in directly in the system console window, which will always be displaying daemon messages, you may prefer to use a separate terminal session for logging in. To do this just run telnet localhost <port> from another shell window and press CTRLZ to log in there. The port should be determined as per this list: Port Type Emulator 10000 TK10 pdp10-ka 10002 Datapoint kludge pdp10-ka 10003 Morton box pdp10-ka 10004 DZ11 simh, pdp10-ks 10007 DTE2 pdp10-kl 10008 DL10 (pdp10-kl in the future?) To shut down ITS, type :lock and then 5down. Log yourself out to avoid the 5 minute grace period: type :logout. When ITS writes SHUTDOWN COMPLETE, it's safe to stop the emulator. Press CTRL\ to escape to the simulator command prompt and quit to close it. If you had a separate telnet user session running you can similarly press CTRL[ and then exit telnet. ITS can optionally use some additional peripheral devices. To attach a simulated GT40 graphics terminal, type ./start gt40. If you run the KA10 emulator, you can use the Knight TV raster display by typing ./start tv11 tvcon. On a TV, type F1 instead of CTRLZ. Here is an overview of the repository: bin - PDP-10 binary files necessary to bootstrap the system. build - build scripts. conf - configuration for building ITS. doc - documentation, most of which appear in the INFO system. src - source code for ITS and all programs. tools - build tools. out - build output. user - optional user files installed in ITS. Terminal Emulators Several emulators for terminals and peripheral processors are built along with ITS. They can be started conveniently with the start script, or separately. Not all terminal emulators are set up to work with all PDP-10 emulators by default. Name Description Type klh10 pdp10-ka pdp10-kl pdp10-ks simh type340 Type 340 vector no yes no no no gt40 GT40 PDP-11 vector no yes no yes yes imlac Imlac PDS-1 vector no yes no no no simh_imlac Imlac PDS-1 vector no yes no no no tv11 Knight TV PDP-11 cpu no yes no no no tvcon Knight TV console raster no yes no no no datapoint Datapoint 3300 text no yes no no no vt52 VT52 text no yes yes yes yes tek Tektronix 4010 vector no yes yes no no Documentation See the doc subdirectory for documentation. There are some short introductions for beginners: How to create a new user DDT cheat sheet for Unix users Basic editing with EMACS TECO survival guide DDT debugging newbie guide Hello MIDAS Hello Maclisp Introduction to Muddle DUMP and itstar Games Printing Assembling ITS Com link mode Logo PDP-6 Networking A list of known ITS machines. How ITS is built. Applications Some major applications: Adventure, game C10, C compiler CLU, programming language. DDT, debugger Emacs, editor Logo, interpreter Mac Hack VI and Tech II, chess programs Maclisp, interpreter and compiler Muddle, interpreter Macsyma, symbolic math Maze War, game Midas, assembler Muscom and musrun, for playing music PDP-11 simulator Scheme, interpreter Spacewar!, game Stanford University Drawing System TECO, editor TOPS-10 and WAITS emulator There is a detailed list of all installed programs.
Read the full README on GitHub

What Hacker News says

3 sources
Logo Adventure for C64 Terrapin Logo https://medium.com/@donhopkins/logo-adventure-for-c64-terrap... >When I was 17, Terrapin published my first commercial code on their C64 Logo utilities disk: a Logo Adventure program, a simple non-graphical game that showed off Logo’s list processing and functional programming capabilities. [...] https://news.ycombinator.com/item?id=23054174 Here is the source code to LLogo in MACLISP, which I stashed from the MIT-AI ITS system. It's a fascinating historical document, 12,480 lines of beautiful practical lisp code, defining where the rubber meets the road, with drivers for hardware like pots, plotters, robotic turtles, TV turtles, graphical displays, XGP laser printers, music devices, and lots of other interesting code and comments. https://donhopkins.com/home/archive/lisp/llogo.lisp Lars Brinkhoff got
Read the rest
some of this code to run in MacLisp on an emulator! (I don't know how much of the historical hardware the emulator supports yet, but he's probably worked on some of that too. ;) ) https://github.com/PDP-10/its/issues/620 Thanks to Lars, here are two revisions of an AI Lab memo about LLOGO: http://bitsavers.org/pdf/mit/ai/aim/AIM-307.pdf http://bitsavers.org/pdf/mit/ai/aim/AIM-307a.pdf And a Logo manual and glossary of PDP-11 Logo: http://bitsavers.org/pdf/mit/ai/aim/AIM-313.pdf http://bitsavers.org/pdf/mit/ai/aim/AIM-315.pdf http://bitsavers.org/pdf/mit/ai/aim/AIM-315a.pdf
In Logo Programming
The Genealogy of ELIZA https://sites.google.com/view/elizagen-org/#h.rle1hgawpigd Kent Pitman's Lisp Eliza from MIT-AI's ITS History Project (sites.google.com) https://news.ycombinator.com/item?id=39373567 xyzzy_plugh on Feb 18, 2024 | next [–] Evergreen quote from TFA: > KMP provided some additional thoughts on his ELIZA: > "The thing about the DOCTOR program, while it was quite elaborate, was that it sort of missed the point of what Weizenbaum was trying to say. It's not that I didn't understand him, but it took me a long time to really come to viscerally understand the seriousness of his point. He said that (paraphrasing, maybe badly, from memory) long before we got to real AI, we would get to things that seemed smart but weren't, and we would overly trust systems that were not really smart. He was, for example, very worried about comp
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uterized launch of nuclear missiles using what was then thought to be AI. But the point of the original ELIZA was not to BE elaborate, it was to be simple, and to show how even a tiny, tiny program could seem smart. It was hard not to think it could be smarter if it were not so tiny, but that misses the point, which was about how easily we were confused, not about how much more effectively we could be confused if more energy were put in. So whether my DOCTOR or any other was making the right point was hard to say. My guess is not." Here's the source for DOCTOR from ITS -- it has a much less extensive set of foul words and doesn't get insulted like his ANIMAL game does: Doctor: https://github.com/PDP-10/its/blob/master/src/games/doc.102 Guess the Animal: https://github.com/PDP-10/its/blob/master/src/games/animal.1... Animal has an extensive list of foul language words: https://github.com/PDP-10/its/blob/master/src/games/animal.1... I accidently offended it by earnestly trying to teach it to distinguish a bear from a pope, and it got mad at me, send angry email to KMP and I, and locked me out -- more details and pointers to Lisp code here: https://news.ycombinator.com/item?id=39414536 I finally sent KMP and ANIMAL an email sincerely apologizing, and apologized ANIMAL directly, and they forgave me so I could play again: Apology Email: https://github.com/PDP-10/its/blob/0f7d67997f9f5d30208e117e7... HANDLE-FOUL-LANGUAGE: https://github.com/PDP-10/its/blob/0f7d67997f9f5d30208e117e7... RECEIVE-APOLOGY: https://github.com/PDP-10/its/blob/0f7d67997f9f5d30208e117e7... At least EMACS has thick skin and lets you type as many dirty words into it as you feel like.
In Vintage Artificial Intelligence: Before It Got Awkward

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