. "2001-03-30Z"^^ . . . . "Current" . . . . . . . "Version 2.2 (V2R2)" . . . "z/OS"@en . "z/OS is a 64-bit operating system for IBM mainframes, produced by IBM. It derives from and is the successor to OS/390, which in turn followed a string of MVS versions. Like OS/390, z/OS combines a number of formerly separate, related products, some of which are still optional."@en . . .