(1) A function of DB2 for z/OS that enables applications on different DB2 subsystems to read from and write to the same data concurrently.
(2) The ability of multiple host systems to concurrently use data that they store on one or more storage devices. The storage facility enables configured storage to be accessible to any, or all, attached host systems. To use this capability, the host program must be designed to support data that it is sharing.
(3) The ability of concurrent subsystems (such as DB2 or IMS DB) or application programs to directly access and change the same data while maintaining data integrity.
(4) The concurrent access of databases by two or more IMSs. The IMSs can be in one operating system image or in separate operating system images. They can share data at two levels: the database level and the block level. See also block-level sharing, database-level sharing.