Xenix is a version of the Unix operating system, licensed by Microsoft from AT&T in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and eventually began distributing it as SCO UNIX (now known as SCO OpenServer).
Xenix was Microsoft's version of Unix intended for use on microcomputers; since Microsoft was not able to license the "UNIX" name itself, they gave it an original name.
Microsoft purchased a license for Version 7 Unix from AT&T in 1979, and announced on August 25, 1980 that it would make it available for the 16-bit microcomputer market. The initial port of Xenix to the Intel 8086/8088 architecture was performed by The Santa Cruz Operation.
Xenix varied from its 7th Edition origins by incorporating elements from BSD, and soon (for a time) possessed the most widely installed base of any Unix flavor due to the popularity of the inexpensive x86 processor.
Microsoft did not sell Xenix directly to end users; instead, they licensed it to software OEMs such as Intel, Tandy, Altos and SCO, who then ported it to their own proprietary computer architectures. Microsoft Xenix originally ran on the PDP-11; the first port was for the Zilog Z8001 16-bit processor. Altos shipped a version for their Intel 8086 based computers early in 1982, Tandy Corporation shipped TRS-XENIX for their 68000-based systems in January 1983, and SCO released their port to the IBM PC in September 1983. A port to the 68000-based Apple Lisa also existed. At the time, Xenix was based on AT&T's UNIX System III.
Version 2.0 of Xenix was released in 1985 and was based on UNIX System V. An update numbered 2.1.1 added support for the Intel 80286 processor. The Sperry PC/IT, an IBM PC AT clone, was advertised as capable of supporting eight users under this version. Subsequent releases improved System V compatibility.
In 1987, SCO ported Xenix to the 386 processor, a 32-bit chip. Xenix 2.3.1 introduced support for i386, SCSI and TCP/IP. SCO's Xenix System V/386 was the first 32-bit operating system available on the market for the x86 CPU Architecture.
Full article ▸