An SRB is a control block that represents a routine that performs
a particular function or service in a specified address space. An
SRB is similar to a TCB in that it identifies a unit of work to the
system. Some characteristics of an SRB are:
- An SRB cannot “own” storage areas. SRB routines can obtain,
reference, use, and free storage areas, but the areas must be owned
by a TCB.
- An SRB has associated with it such resources as a dispatchable
unit access list (DU-AL), a functional recovery routine (FRR) stack,
a linkage stack, and a CPU timer value.
The routine that performs the function or service is called the SRB routine; initiating the process is called scheduling an SRB.