Improved control interval processing is faster because functions
have been removed from the path. However, improved control interval
processing causes several restrictions:
- The object must not be empty.
- The object must not be compressed.
- The object must be one of the following:
- An entry-sequenced, fixed-length, or variable-length RRDS cluster.
- The data component of an entry-sequenced, key-sequenced, linear,
fixed-length, or variable-length RRDS cluster.
- The index component of a key-sequenced cluster (index records
must not be replicated).
- Control intervals must be the same size as physical records. When
you use the access method services DEFINE command to define the object,
specify control interval size equal to a physical record size used
for the device on which the object is stored. VSAM uses physical record
sizes of (n x 512) and (n x 2048), where n is a positive integer from
1 to 16. The physical record size is always equal to the control interval
size for an index component.