VSAM RLS provides an environment in which multiple CICS® transaction servers can directly access a shared VSAM data set. At the same time, batch jobs can share nonrecoverable data sets for reading and updating while CICS is using them. VSAM RLS and CICS can also share recoverable data sets for reading when the data sets have share options defined. Batch jobs are able to share recoverable data sets for reading when they are opened in RLS mode.

Figure 1 is an example of how DFSMStvs can be used with CICS and with batch jobs. DFSMStvs works with RRS to commit the VSAM data set changes and release the corresponding VSAM locks.

Figure 1. Batch jobs designed to use transactional recovery

While VSAM RLS provides multisystem data sharing for CICS, DFSMStvs is intended for non-CICS applications. From a logical perspective, CICS and DFSMStvs do the same kind of work. DFSMStvs and CICS complement one another by using the same locking protocols and the same type of commit and backout protocol. If both DFSMStvs and CICS want to update the same group of records, one application has to complete its current unit of recovery before the other can begin.