Special Real Time Operating System (SRTOS) is a discontinued IBM real time operating system, originally designed for use in the electricity industry, but later also applied in other areas of industrial process control. It formed part of the Realtime Plant Management System (RPMS) and Advanced Control System (ACS). Rather than a standalone operating system, it was designed as an extension to the OS/VS1 and OS/VS2 (later MVS) operating systems. It was also used in the paper industry. SRTOS was originally released in 1976, but continued to be used through the 1980s.
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Special Real Time Operating System Wikipedia(Text) CC BY-SA