Unit 8, Section 5: N-way Data Sharing and OSAM Caching

This video describes n-way data sharing, which allows up to 255 IMSs in up to 32 z/OSs to share the same set of databases with complete update authority (SHARELVL permitting). This technology requires use of Coupling Facility (CF) structures and use of IRLM. This video also covers the CF Cache structures for IMS (OSAM or VSAM), which maintain a “where used” report that indicates which IMS system has a copy of a specific block in its storage.