Often abbreviated as ZOS, z/OS is IBM
operating system. It is a 64-bit operating system
that supports Java
‘s, and TCP/IP
to name a few features. z/OS.e is a specially priced, slimmed-down offering of z/OS. It provides select functions but uses the same code base as z/OS and invokes an operating environment that is comparable to z/OS in service, management, reporting, and reliability. The first name for IBM’s mainframe operating system was MVS
(Multiple Virtual Storage), which was succeeded first by OS/390 and then z/OS.
See also MVS.