Sphere Records

Sphere records might have related extension records. Extension records are created when the maximum record size of the BCS cannot contain a new component entry for a VSAM data set or alternate DEFINE USERCATALOG command. The default is 32400 bytes.

An alternate index or generation data group must be able to fit within an extension record.

An extension record is created when:

An alternate index or generation data group is defined and does not fit in the current sphere record.
A path is defined and the entry in the association cell does not fit in the sphere record.
An extension cell will be created if there is a component entry for an alternate index or generation data set which can be moved into the extension record. The path entry must remain in the primary sphere record.
Volumes are added to a cluster or alternate index and the volume cell does not fit in the sphere record.

The key of the extension record is the base cluster or generation data group name and the pad character.

The pad character is a binary number. The first extension is X'01', the second extension is X'02', and so on, up to the 255th extension which is X'FF'. The maximum number of extensions allowed is 255.

A component level entity is moved to the new extension record whether it is the component being updated or the last component on the current sphere record. For a VSAM sphere record, this is an alternate index. For a generation data group sphere record, the generation data set component is moved. Only one component resides in each extension record.