OS/390 is an IBM operating system for the System/370 and System/390 IBM mainframe computers. It is basically a rebranded version of MVS with added UNIX System Services. The OS/390 base includes a Communication Server that includes VTAM, the VTAM AnyNet feature, TCP/IP, and TIOC . It provides SNA (3270), APPC , High Performance Routing , ATM support, sockets, and RPC.

OS/390 was introduced in late 1995 as the follow-on to MVS. In December, 2001, IBM extended OS/390 to the 64-bit zSeries processors and added various other improvements, and the result is now named z/OS. IBM ended support for the older OS/390-branded versions in late 2004.

See also

• Linux on zSeries
• OS/360
• z/TPF
• z/VM
• z/VSE

References