General Comprehensive Operating System

Developed by General Electric in 1962 – and still in use today, largely through emulation – General Comprehensive Operating System (GCOS) is a family of operating systems oriented towards mainframe computers.

Traces of GCOS influence remain today in modern UNIX systems, in particular the gecos field – an entry in the /etc/passwd file on Unix and similar operating systems – typically used to record general information about the account or its user(s).