Coherent (operating system)

The Coherent operating system was a Version 7 Unix clone by the now-defunct Mark Williams Company, originally produced for the PDP-11 in 1980. A port was introduced in 1983 as the first Unix-like system for IBM PC compatible computers. Coherent was able to run on most Intel-based PCs with Intel 8088, 286, 386, and 486 processors. Coherent version 3 for Intel-based PCs required at least a 286, Coherent version 4 for Intel-based PCs required at least a 386. Like a true Unix, Coherent was able to multitask and support multiple users. From version 4 on Coherent also had support for X11 and MGR windowing systems.