6.5. DFSMStvs overview
This section provides an overview of DFSMStvs including its relationship with RLS.
6.5.1. The RLS connection
As we saw in the previous chapter on RLS, which was introduced in DFSMS/MVS 1.3, RLS provides for a new mode of access to VSAM data. Also, we learned that RLS uses the System/390® Coupling Facility to provide the lock structures and data caching abilities to manage and ensure data integrity when VSAM data is shared. This is the reason that a Coupling Facility is required for RLS even if you want to share VSAM data in a monoplex. DFSMStvs extends the sharing of data to CICS and batch level sharing similarly maintaining data integrity for reads and updates. To accomplish this, DFSMStvs must provide the same abilities ...