7.23 DFSMStvs introduction DFSMStvs addresses key requirements from customers Objective: Provide transactional recovery within VSAM VSAM RLS allows batch sharing of recoverable data sets for read VSAM RLS provides locking and buffer coherency CICS provides logging and two-phase commit protocols DFSMStvs allows batch sharing of recoverable data sets for update Logging provided using the MVS system logger Two-phase commit and back out using MVS recoverable resource management services Figure 7-32 DFSMS Transactional VSAM Services (DFSMStvs) introduction Why to use DFSMS Transactional VSAM Services (DFSMStvs) There following key requirements were expressed by customers running CICS applications in RLS mode: Address the batch window problem for CICS and batch sharing of VSAM data sets. In 7.12, "The batch window problem" on page 395, we discuss the problem with the batch window. Customers reported batch windows ranging from two to ten hours. The programs run during the batch window consisted of both in-house applications and vendor-written applications. Allow batch update sharing concurrent with CICS use of recoverable data. Allow multiple batch update programs to run concurrently. Allow programs to interact with multiple resource managers such as IMS and DB2. Allow full transactional read/write access from new JavaTM programs to existing VSAM data. Objective of DFSMStvs The objective of DFSMStvs is to provide transactional recovery directly within VSAM. It is an extension to VSAM RLS. It allows any job or application that is designed for data sharing to read/write share VSAM recoverable files. Chapter 7. DFSMS Transactional VSAM Services 419