Recoverable resource management services (RRMS) is part of the operating system and comprises registration services, context services, and recoverable resource services (RRS). RRMS provides the context and unit of recovery management under which DFSMStvs participates as a recoverable resource manager. This topic briefly discusses conceptual information about contexts and units of recovery as they relate to DFSMStvs.

A context is a unit of recovery together with the associated application programs, resource managers, and protected resources. Resource managers perform services for contexts and units of recovery. A resource manager allocates resources to a context and assigns units of recovery to it. A resource manager also allocates resources to a unit of recovery and assigns lock ownership to it. A unit of recovery is work that is done by or on behalf of a context between one point of consistency and another. A context represents a work request in an application, and the life of a context consists of a series of units of recovery, with zero or one unit of recovery associated with the context at any point in time.

Related reading: For more information about RRS, units of recovery, and contexts, see z/OS MVS Programming: Resource Recovery.