SCO Xenix 2.3.4

In the late 1970's, Microsoft licensed the UNIX source code from AT&T, and produced their own version of Unix. At the time, AT&T was not licencing the Unix name, so Microsoft called the product Xenix. MS did not sell the product directly, rather they licenced it to OEMs such as Intel, Tandy, Altos and SCO. These are generated screenshots of the SCO Xenix 2.3.4 installation routine.

The early versions of Xenix were written for the 8086 processor, and did not include TCP/IP networking. Later versions were TCP/IP-capable, but the TCP/IP and streams packages were sold separately from the operating system. Basic serial networking (UUCP) was built in, but you needed to recompile the kernel to use more than two serial ports. Both the kernel source code and the compiler were separate packages.