Descriptive Parameters

The following access method services parameters provide descriptive information:

INDEXED|NONINDEXED|NUMBERED|LINEAR parameter—Specifies the type of data organization used (key sequenced, entry sequenced, relative record, or linear).
RECORDSIZE parameter—Specifies the average and maximum lengths of data records. The RECORDSIZE parameter is not used for a linear data set.
A variable-length RRDS is defined using NUMBERED and RECORDSIZE, where the average and maximum record length must be different.

If the actual length of an entry-sequenced, key-sequenced, or variable-length RRDS record is less than the maximum record length, VSAM saves disk space by storing the actual record length in the record definition field (RDF). The RDF is not adjusted for fixed-length RRDSs.
KEYS parameter—Specifies the length and position of the key field in the records of a key-sequenced data set.
CATALOG parameter—Specifies the name and password of the catalog in which the cluster is to be defined.
VOLUMES parameter—Specifies the volume serial numbers of the volumes on which space is allocated for the cluster. You can specify up to 59 DASD volumes.
RECORDS|KILOBYTES|MEGABYTES|TRACKS|CYLINDERS parameter—Specifies the amount of space to allocate for the cluster. The CYLINDERS, TRACKS, MEGABYTES, KILOBYTES, and RECORDS parameters are permitted for a linear data set. If you specify the RECORDS parameter for a linear data set, the system allocates space with the number of control intervals equal to the number of records. (Linear data sets do not have records; they have objects that are contiguous strings of data.)
RECATALOG parameter—Specifies if an entry is recreated from information in the VSAM volume data set (VVDS), or defined for the first time.
REUSE|NOREUSE parameter—Specifies if the cluster is reusable for temporary storage of data. See Reusing a VSAM Data Set as a Work File.
BUFFERSPACE parameter—Specifies the minimum amount of I/O buffer space that must be allocated to process the data set. See Determining I/O Buffer Space for Nonshared Resource.