OS/390 is an IBM operating system for the System/390 IBM mainframe computers. OS/390 was introduced in late 1995 in an effort to simplify the packaging
called MVS, is the most commonly used operating system on the System/370, System/390 and IBM Z IBM mainframe computers. IBM developed MVS, along with OS/VS1
environment for IBM mainframe operating systems, including OS/360 MVT, OS/VS2 (SVS), MVS, OS/390, and z/OS. In computing, time-sharing is a design technique that
string of MVS versions. Like OS/390, z/OS combines a number of formerly separate, related products, some of which are still optional. z/OS has the attributes