z/OS V1R6.0 DFSMS Access Method Services for Catalogs

DEFINE CLUSTERAbbreviation: NSPNDSPEED|RECOVERYSpecifies whether the data component’s control areas are to be preformattedduring loading.This parameter is only considered during the actual loading (creation) of a dataset. Creation occurs when the data set is opened and the high-used RBA isequal to zero. After normal CLOSE processing at the completion of the loadoperation, the physical structure of the data set and the content of the data setextents are exactly the same, regardless of which option is used. Anyprocessing of the data set after the successful load operation is the same, andthe specification of this parameter is not considered.If you use RECOVERY, the initial load takes longer because the control areasare first written with either empty or software end-of-file control intervals.These preformatted control intervals are then updated, using update writeswith the data records. When SPEED is used, the initial load is faster.SPEEDDoes not preformat the data component’s space.If the initial load is unsuccessful, you must load the data set again fromthe beginning because VSAM cannot determine the location of your lastcorrectly written record. VSAM cannot find a valid end-of-file indicatorwhen it searches your data records.RECOVERYDoes preformat the data component’s space prior to writing the datarecords.If the initial load is unsuccessful, VSAM can determine the location of thelast record written during the load process.Abbreviation: RCVYSTORAGECLASS(class)For SMS-managed data sets: Gives the name, 1-to-8 characters of the storageclass.Your storage administrator defines the names of the storage classes you canuse. A storage class is assigned either when you use STORAGECLASS, or anACS routine selects a storage class for the new data set. The storage classprovides the storage attributes that are specified on the UNIT and VOLUMEoperand for non-SMS managed data sets. Use the storage class to select thestorage service level to be used by SMS for storage of the data set. If SMS isinactive and STORAGECLASS is used, the DEFINE will be unsuccessful.STORAGECLASS cannot be selected as a subparameter of DATA or INDEX.Abbreviation: STORCLASTO(date)|FOR(days)Specifies the retention period for the cluster being defined. If neither TO norFOR is used, the cluster can be deleted at any time. TheMANAGEMENTCLASS maximum retention period, if selected, limits theretention period specified by this parameter.For non-SMS-managed data sets, the correct retention period is reflected in thecatalog entry. The VTOC entry cannot contain the correct retention period.Enter a LISTCAT command for the correct expiration date.Chapter 14. DEFINE CLUSTER 165