OS/360 and successors

OS/360 was an operating system with batch processing capability, which IBM had announced their System/360-Großrechner in 1964. OS/360 was one of the first operating systems, mass random access memory ( eg hard disks ) presuppose.


OS/360 was developed as a family of three control programs, each new program was both larger and equipped with more functionality. The simplest version, the PCP (English Primary Control Program ), could each perform a task, and thus had to edit the jobs sequentially. The next version, the MFT (English Multiprogramming with a Fixed number of Tasks ), added the functions added a limited multitasking. There were only a defined number of tasks are executed simultaneously, the necessary memory allocations for jobs had to be defined before its launch. The latest version, the MVT (English multiprogramming with a variable number of tasks), allowed to perform any number of tasks, and a dynamic memory utilization by the tasks, that is, of a task assigned storage area could be enlarged during the execution or. Decrease OS/360 also introduced the Job Control Language (JCL ).

OS/360 was delivered late because there was a combination of several organizational problems at IBM. The whole project was technically very demanding, and IBM did not yet have the necessary experience with such large software projects. The originally scheduled delivery dates in 1965 ( for the simple version ) and in 1966 ( for the other two versions ) could not be observed. PCP was only in 1966, MFT and MVT could be delivered until 1967.

OS/360 has been further developed, as was later hardware with the capability of virtual addressing for the System/370-Reihe available. From MFT was OS/VS1 from MVT OS/VS2; OS/VS2 later was renamed after its development in MVS ( Multiple Virtual Storage engl. ).

Today OS/360 public domain and can be downloaded free of charge. Besides the original System/360-Hardware OS/360 can also be run on Microsoft Windows and Linux systems with the free Hercules emulator today.