Developed by: Microsoft
Launched: 1980

The version of Unix developed by Microsoft.

In 1979, Microsoft purchased a license for UNIX System V from AT&T and announced on August 25, 1980, its intention to port it to 16-bit microprocessors.

XENIX was never sold directly to end users; instead, Microsoft licensed it to computer manufacturers who wanted to use it in their computers.

The first port of XENIX was for a Zilog Z8003 microprocessor.

Tandy Corporation purchased a license in January 1983 to sell XENIX with its Motorola 68000 processor-based computers.

Santa Cruz Operations (SCO) purchased a license in September 1983 to sell XENIX to users of computers with the Intel 8086 processor.

Microsoft abandoned XENIX when it signed an agreement to co-develop the OS/2 operating system with IBM. And it agreed to sell SCO its rights to XENIX in exchange for 25% of SCO.

SCO distributed a port of XENIX for the Intel 80286 processors in 1985.

It later marketed a port for the Intel 80386 processors, which was known as XENIX System V i386.

SCO thus became the largest distributor of XENIX, which it eventually renamed SCO UNIX.