OS/360, officially known as IBM System/360 Operating System, is a discontinued batch processing operating system developed by IBM for their then-new System/360 mainframe computer, announced in 1964; it was influenced by the earlier IBSYS/IBJOB and Input/Output Control System packages for the IBM 7090/7094 and even more so by the PR155 Operating System for the IBM 1410/7010 processors. Wikipedia