INTERACTIVE Systems Corporation (ISC) was a US-based software company and the first vendor of the Unix

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 operating system outside AT&T

AT&T

AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...

, operating from Santa Monica, CA.

ISC's 1977 offering, IS/1, was a Version 6 Unix

Version 6 Unix

Sixth Edition Unix, also called Version 6 Unix or just V6, was the first version of the Unix operating system to see wide release outside Bell Labs. It was released in May 1975 and, like its direct predecessor, targeted the DEC PDP-11 family of minicomputers...

 variant enhanced for office automation for the PDP-11

PDP-11

The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...

. IS/3 and IS/5 were enhanced versions of Unix System III

UNIX System III

UNIX System III was a version of the Unix operating system released by AT&T's Unix Support Group . It was first released outside of Bell Labs in 1982. UNIX System III was a mix of various AT&T Unixes: PWB/UNIX 2.0, CB UNIX 3.0, UNIX/TS 3.0.1 and UNIX/32V...

 and System V

UNIX System V

Unix System V, commonly abbreviated SysV , is one of the first commercial versions of the Unix operating system. It was originally developed by American Telephone & Telegraph and first released in 1983. Four major versions of System V were released, termed Releases 1, 2, 3 and 4...

 for PDP-11 and VAX

VAX

VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...

. ISC Unix ports to the IBM PC

IBM PC

The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...

 included a variant of System III, developed under contract to IBM

IBM

International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

, known as PC/IX (Personal Computer Interactive eXecutive), with later versions branded 386/ix and finally INTERACTIVE UNIX

INTERACTIVE UNIX

INTERACTIVE UNIX System V/386 is a port of the UNIX System V operating system for Intel x86 processors.The system was first released by INTERACTIVE Systems Corporation as 386/ix in 1985. At that time it was based on System V.3.0. Later versions were based on System V.3.2...

 System V/386 (based on System V Release 3.2). ISC was AT&T's "Principal Publisher" for System V.4 on the Intel platform.

ISC was also involved in the development of VM/IX (Unix as a guest OS in VM/CMS), IX/360 (native Unix on the System/360

System/360

The IBM System/360 was a mainframe computer system family first announced by IBM on April 7, 1964, and sold between 1964 and 1978. It was the first family of computers designed to cover the complete range of applications, from small to large, both commercial and scientific...

) and AIX

AIX operating system

AIX AIX AIX (Advanced Interactive eXecutive, pronounced "a i ex" is a series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms...

, again under contract to IBM. Several former ISC staff founded Segue Software which partnered with Lotus Development

Lotus Software

Lotus Software is a software company with headquarters in Westford, Massachusetts...

 to develop the Unix version of Lotus 1-2-3

Lotus 1-2-3

Lotus 1-2-3 is a spreadsheet program from Lotus Software . It was the IBM PC's first "killer application"; its huge popularity in the mid-1980s contributed significantly to the success of the IBM PC in the corporate environment.-Beginnings:...

 and with Peter Norton Computing

Peter Norton Computing

Peter Norton Computing, Inc., was a software company founded by Peter Norton. The first and most notable software package it produced is the Norton Utilities. Another very popular software was Norton Commander, especially the DOS version. In 1990, the company was acquired by Symantec. The...

 to develop the Unix version of the Norton Utilities

Norton Utilities

Norton Utilities is a utility software suite designed to help analyze, configure, optimize and maintain the computer. The current version 15 of Norton Utilities Premier Edition for Windows XP/Vista/7 was released December 27, 2010....

.

ISC was acquired by Eastman Kodak Company in 1988,

which sold its ISC Unix operating system assets to Sun Microsystems

Sun Microsystems

Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...

 on September 26, 1991. Kodak sold the remaining parts of ISC to SHL Systemhouse Inc in 1993. Final support for INTERACTIVE System V/386 from Sun ended on July 23, 2006.