Tenth Edition Unix, also known as Version 10 Unix or V10, was the last version of the Research Unix

Research Unix

Research Unix is a term used to refer to versions of the Unix operating system for DEC PDP-7, PDP-11, VAX and Interdata 7/32 and 8/32 computers, developed in the Bell Labs Computing Science Research Center ....

 operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 developed and used internally at Bell Labs

Bell Labs

Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...

. "Released" in 1989, it was the successor of V9

Version 9 Unix

Ninth Edition Unix, also known as Version 9 Unix or V9, was a version of the Research Unix operating system developed and used internally at the Bell Labs Information Sciences Research Division, "released" in September 1986. V9 was the successor to V8, and the predecessor to the last Research Unix...

. There was no V11; Unix development at Bell Labs was discontinued in favor of Plan 9

Plan 9 from Bell Labs

Plan 9 from Bell Labs is a distributed operating system. It was developed primarily for research purposes as the successor to Unix by the Computing Sciences Research Center at Bell Labs between the mid-1980s and 2002...

.

Novelties in V10 included graphics typesetting

Typesetting

Typesetting is the composition of text by means of types.Typesetting requires the prior process of designing a font and storing it in some manner...

 tools designed to work with troff

Troff

troff is a document processing system developed by AT&T for the Unix operating system.-History:troff can trace its origins back to a text formatting program called RUNOFF, written by Jerome H. Saltzer for MIT's CTSS operating system in the mid-1960s...

, a C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

 interpreter

Interpreter (computing)

In computer science, an interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language...

, animation programs, and several tools later found in Plan 9: the Mk build tool and the rc shell.

V10 was the basis for Douglas McIlroy

Douglas McIlroy

Malcolm Douglas McIlroy is a mathematician, engineer, and programmer. As of 2007 he is an Adjunct Professor of Computer Science at Dartmouth College. Dr...

 and Jonathan Reeds' IX

IX (operating system)

IX was a security-focused variant of the Tenth Edition Research Unix operating system, developed by Douglas McIlroy and James Reeds at Bell Labs in 1988.-External links:*...

 multilevel-secure

Multilevel security

Multilevel security or Multiple Levels of Security is the application of a computer system to process information with different sensitivities , permit simultaneous access by users with different security clearances and needs-to-know, and prevent users from obtaining access to information for...

operating system.