Nonrecoverable data sets are not part of transactional recovery. Commit and rollback logging do not apply to these data sets. Because transactional recovery is not required, VSAM RLS permits read and write sharing of nonrecoverable data sets concurrently by DFSMStvs, CICS, and non-CICS applications. Any application can open the data set for output in RLS mode.

VSAM RLS provides record locking and buffer coherency across the CICS and non-CICS read/write sharers of nonrecoverable data sets. However, the record lock on a new or changed record is released as soon as the buffer that contains the change has been written to the CF cache and DASD. This differs from the case in which a DFSMStvs or CICS transaction modifies VSAM RLS recoverable data sets and the corresponding locks on the added and changed records remain held until the end of the transaction.

For sequential and skip-sequential processing, VSAM RLS does not write a modified control interval (CI) until the processing moves to another CI or an ENDREQ is issued by the application. If an application or the VSAM RLS server ends abnormally, these buffered changes are lost. To help provide data integrity, the locks for those sequential records are not released until the records are written.

While VSAM RLS permits read and write sharing of nonrecoverable data sets across DFSMStvs and CICS and non-CICS applications, most applications are not designed to tolerate this sharing. The absence of transactional recovery requires very careful design of the data and the application.