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

DEFINE CLUSTERThe DEFINE CLUSTER command builds a cluster entry, a data entry, and an indexentry to define the key-sequenced cluster, EXAMPLE.KSDS2. The DEFINECLUSTER command allocates space separately for the cluster’s data and indexcomponents.The parameter that applies to the cluster is NAME which specifies that thecluster’s name is EXAMPLE.KSDS2.The parameters that apply only to the cluster’s data component are enclosed in theparentheses following the DATA keyword:vvvvvvvRECORDS specifies that an amount of tracks equal to at least 500 records is tobe allocated for the data component’s space. When the data component isextended, it is to be extended in increments of tracks equal to 100 records.EXCEPTIONEXIT specifies the name of the exception exit routine, DATEXIT,that is to be processed if an I/O error occurs while a data record is beingprocessed.ERASE specifies that the cluster’s data is to be erased (overwritten with binaryzeros) when the cluster is deleted.FREESPACE specifies the amounts of free space to be left in the datacomponent’s control intervals (20%) and the control areas (10% of the controlintervals in the control area) when data records are loaded into the cluster.KEYS specifies the location and length of the key field in each data record. Thekey field is 6 bytes long and begins in the fifth byte (byte 4) of each data record.RECORDSIZE specifies that the cluster’s records are variable length, with anaverage size of 80 bytes and a maximum size of 100 bytes.VOLUMES specifies that the cluster is to reside on volume VSER01.The parameters that apply only to the cluster’s index component are enclosed inthe parentheses following the INDEX keyword:vvRECORDS specifies that an amount of tracks equal to at least 300 records is tobe allocated for the index component’s space. When the index component isextended, it is to be extended in increments of tracks equal to 300 records.VOLUMES specifies that the index component is to reside on volume VSER01.The CATALOG parameter specifies that the cluster is to be defined in a usercatalog, USERCAT4.Define an Entry-Sequenced Cluster Using a Model: Example 8In this example, two entry-sequenced clusters are defined. The attributes of thesecond cluster defined are modeled from the first cluster.//DEFCLU7 JOB ...//STEP1 EXEC PGM=IDCAMS//SYSPRINT DD SYSOUT=A//SYSIN DD *DEFINE CLUSTER -(NAME(GENERIC.A.BAKER) -VOLUMES(VSER02) -RECORDS(100 100) -RECORDSIZE(80 80) -NONINDEXED ) -CATALOG(USERCAT4)DEFINE CLUSTER -(NAME(GENERIC.B.BAKER) -MODEL(GENERIC.A.BAKER USERCAT4)) -CATALOG(USERCAT4)/*172 z/OS V1R6.0 DFSMS Access Method Services for Catalogs