Multiple Console Time Sharing System
The Multiple Console Time Sharing System (MCTS) was an operating system developed by General Motors Research Laboratories in the 1970s for the Control Data Corporation STAR-100 supercomputer. MCTS was built to support GM's computer-aided design (CAD) applications. MCTS was based on Multics. See also
GM-NAA I/O
SHARE Operating System
Timeline of operating systems

References

Further reading
 

Discontinued operating systems
Multics-like
Proprietary operating systems
Time-sharing operating systems
Supercomputer operating systems