Michigan Terminal System
MTS is an
operating system for
IBM System/360 and its successors that was developed jointly by the following institutions:
Popular programs developed for MTS include
MAD, the FORMAT text formatting system and the CONFER conferencing system.
MTS doesn't implement directories, but there is a de facto two-tier grouping of files owing to the inclusion in a file's name of its owner's four-character MTS callsign.