ITS (Incompatible Timesharing System)

E529383

operating system research operating system time-sharing operating system

ITS (Incompatible Timesharing System) was an influential early time-sharing operating system developed at MIT’s AI Lab, known for its hacker-friendly environment and role in the development of much of early AI and Lisp software.

Try in SPARQL Jump to: Surface forms Disambiguation Statements Elicitation Referenced by

All labels observed (2)

Label	Occurrences
Incompatible Timesharing System	2
ITS (Incompatible Timesharing System) canonical	1

How this entity was disambiguated

This entity first appeared as the object of triple T5582302 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.

NED1 Entity disambiguation (via context triple) gpt-5-mini-2025-08-07

Target entity: ITS (Incompatible Timesharing System)
Context triple: [Maclisp, platform, ITS (Incompatible Timesharing System)]

A. Multics
Multics (Multiplexed Information and Computing Service) was an influential pioneering time-sharing operating system developed in the 1960s that introduced many concepts later adopted by modern operating systems, including Unix.
B. TOPS-20
TOPS-20 is a mainframe time-sharing operating system from the 1970s and 1980s, known for its advanced interactive features and use on DEC’s PDP-10 systems.
C. RSX-11
RSX-11 is a family of real-time, multi-user operating systems for PDP-11 minicomputers, widely used in industrial and embedded applications in the 1970s and 1980s.
D. TOPS-10
TOPS-10 is a historic time-sharing operating system for DEC's PDP-10 mainframe computers, widely used in the 1960s and 1970s in academic and research environments.
E. TENEX operating system
TENEX operating system is an early time-sharing operating system for the PDP-10 that introduced advanced virtual memory and interactive computing features influential in later systems.
F. None of above. chosen
G. Unsure - the case is ambiguous/there is not enough information to decide.

NED2 Entity disambiguation (via description) gpt-5-mini-2025-08-07

Target entity: ITS (Incompatible Timesharing System)
Target entity description: ITS (Incompatible Timesharing System) was an influential early time-sharing operating system developed at MIT’s AI Lab, known for its hacker-friendly environment and role in the development of much of early AI and Lisp software.

A. Multics
Multics (Multiplexed Information and Computing Service) was an influential pioneering time-sharing operating system developed in the 1960s that introduced many concepts later adopted by modern operating systems, including Unix.
B. TOPS-20
TOPS-20 is a mainframe time-sharing operating system from the 1970s and 1980s, known for its advanced interactive features and use on DEC’s PDP-10 systems.
C. RSX-11
RSX-11 is a family of real-time, multi-user operating systems for PDP-11 minicomputers, widely used in industrial and embedded applications in the 1970s and 1980s.
D. TOPS-10
TOPS-10 is a historic time-sharing operating system for DEC's PDP-10 mainframe computers, widely used in the 1960s and 1970s in academic and research environments.
E. TENEX operating system
TENEX operating system is an early time-sharing operating system for the PDP-10 that introduced advanced virtual memory and interactive computing features influential in later systems.
F. None of above. chosen

Statements (60)

Predicate	Object
instanceOf	operating system ⓘ research operating system ⓘ time-sharing operating system ⓘ
abbreviation	ITS NERFINISHED ⓘ
basedOn	DEC PDP-10 architecture ⓘ DEC PDP-6 architecture ⓘ
contemporaneousWith	Multics NERFINISHED ⓘ TENEX NERFINISHED ⓘ TOPS-10 NERFINISHED ⓘ
countryOfOrigin	United States of America ⓘ surface form: United States
culturalRole	central platform for early hacker community at MIT ⓘ incubator for free software ideas ⓘ
designedFor	PDP-10 NERFINISHED ⓘ PDP-6 NERFINISHED ⓘ
developer	MIT Artificial Intelligence Laboratory NERFINISHED ⓘ Massachusetts Institute of Technology NERFINISHED ⓘ
endOfSupport	early 1990s ⓘ
feature	extensive debugging facilities ⓘ job control and process inspection ⓘ networked file access between ITS machines ⓘ real-time multi-user time-sharing ⓘ terminal-based user interface ⓘ
fullName	Incompatible Timesharing System NERFINISHED ⓘ
historicalPeriod	mainframe era ⓘ
historicalSignificance	major influence on design of interactive computing environments ⓘ
hostedSystem	Maclisp-based AI programs ⓘ early interactive fiction games ⓘ early versions of Emacs ⓘ
inception	1967 ⓘ late 1960s ⓘ
influenced	Emacs text editor NERFINISHED ⓘ GNU project culture ⓘ Lisp Machine operating systems ⓘ Zork (early versions) NERFINISHED ⓘ hacker ethic ⓘ
license	non-commercial research use ⓘ
notableFor	hacker-friendly environment ⓘ influence on Emacs development ⓘ influence on Lisp software development ⓘ influence on early AI research ⓘ influence on early networked computing ⓘ influence on hacker culture ⓘ open, non-password security model ⓘ support for interactive debugging ⓘ support for multiple terminals and users ⓘ support for real-time interaction with running programs ⓘ
primaryLocation	MIT AI Lab NERFINISHED ⓘ MIT Building 26 NERFINISHED ⓘ
programmingLanguage	Fortran NERFINISHED ⓘ Lisp NERFINISHED ⓘ MACLISP NERFINISHED ⓘ MIDAS assembler NERFINISHED ⓘ assembly language ⓘ
securityModel	minimal access control ⓘ no passwords by default ⓘ
usedFor	Lisp program development ⓘ artificial intelligence research ⓘ computer graphics experiments ⓘ early computer games ⓘ interactive program development ⓘ

How these facts were elicited

Referenced by (3)

Full triples — surface form annotated when it differs from this entity's canonical label.

Maclisp → platform → ITS (Incompatible Timesharing System) ⓘ

EINE → operatingSystem → ITS (Incompatible Timesharing System) ⓘ

this entity surface form: Incompatible Timesharing System

MIT AI Lab software environment → basedOnOperatingSystem → ITS (Incompatible Timesharing System) ⓘ