In [[IBM]] [[zSeries]] [[mainframe computer]]scomputing, a '''Parallel Sysplex''' is a [[computer cluster|cluster]] of zSeries[[IBM mainframesmainframe]]s acting together asin onea single system image, usually with [[Sysplexz/OS]]. ItA Parallel Sysplex combines data sharing (typically using [[Peer to Peer Remote Copy]]), and [[parallel computing]] to allow a cluster of up to 32 computers to share a workload for [[high performance computing|high performance]] and [[high availability]].
The forerunner of the Parallel Sysplex was the '''Virtual Coupling''', a technique which allowed up to 12 [[IBM 3090]] systems to execute jobs in parallel. The true Parallel Sysplex was introduced with thethen-new [[zSeriesmainframe 900]]models in April of, [[1994]]. IBM continues to improve and enhance Parallel Sysplex.
Major components of a Parallel Sysplex include:
* [[Coupling Facility]] (CF) hardware, allowing multiple processors to share, cache, update, and balance data access;
* A [[Sysplex Timer]] to synchronize the clocks of all member systems.
IBM will replace the Sysplex Timer with [[Server Time Protocol]] starting in late 2005.
