Summarised
A operating system that was developed by bell labs in the 1970s
UNIX is a operating system that was developed in the 1970s. It is a multi-user and multi-tasking operating system. It is a command line operating system but some versions have a graphical user interface. It is a proprietary operating system. Many operating systems are based on UNIX or a UNIX like system. 1
History
UNIX was developed in the 1970s by Ken Thompson, Dennis Ritchie and others at Bell Labs.
Standards
POSTIX is a standard for UNIX like operating systems. It is a set of standards that a operating system must meet to be considered a UNIX like operating system.