Sysplex

Multiple z/OS systems that need to share resources can be connected together using the Sysplex technology.
It allows connecting up to 32 images together, usually using channels and coupling facilities.

Some sites might have multiple sysplexes, for example one for production and one for dev/test systems

XCF is a basic and common tool used in sysplex environments

Time synchronisation

It is vital that all systems within a sysplex thinks it is the same time.
To resolve this Server Time Protocol can be used.

More complex sysplexes

A basic sysplex is when multiple z/OS systems communicate with just channels

Most sysplexes will have one or more ICFs.
These are called Parallel Sysplexes