Cross-system extended (XES) services allow multiple instances of an authorized application or subsystem, running on different systems in a sysplex, to implement high-performance, high-availability data sharing by using a coupling facility. Applications can maintain and access data in three types of structures (list, lock, or cache). Features of the different structures, available through the use of XES services, include the ability to:

• Share data organized as a set of lists (list structure)
• Determine whether a local copy of cached data is valid (cache structure)
• Automatically notify other users when a data update invalidates their local copies of cached data (cache structure)
• Implement efficient, customized locking protocols, with user-defined lock states and contention management (lock structure).