OS/390 (or zOS) is a mainframe operating system used on IBM's S390 mainframe systems. OS/390 is also one of the operating systems that Oracle runs on.
Oracle 10g is fully supported on OS/390, however Oracle 11g will only be available on Linux for System Z.
Oracle announced that they will end error correction support for all products on OS/390 on 31 July 2012 (Matalink note 464660.1). Customers will still be able to utilize their hardware investment by migrating to Linux for System Z.
Understanding OS/390 Jargon
OS/390 jargon can sometimes be extremely intimidating. Here are some common definitions that will help you to get up to speed with the OS/390 operating system:
APAR (authorized program analysis reports): If one needs to correct a serious problem that occurs on a system before a PTF is ready, IBM Support can supply you with an APAR on request.
MPM: Multi Processing Monitor (MPM) is the Oracle address space running to support an Oracle instance.
PDS (Partition Data Set): A library to store members (files) in.
PTF (program temporary fix): When IBM Support correct a problem they will supply their customers a tested PTF. Although you may not have the problem, it is wise to install the PTF on your system for preventive reasons.