There are two types of BCS records: the sphere record and the nonsphere record. A sphere record contains one or more components. The key length of any record is 45 bytes, consisting of a 44-byte data set or object name and a 1-byte pad character to indicate an extension record.

Records and components are a logically related group of cells. These logical groupings are physically adjacent in a sphere record. An example of a component is the index of a VSAM data set.