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

programs, it provides a means of generating standardscreen panels and interactive dialogues between theapplication programmer and terminal user.Interactive Storage Management Facility (ISMF). Theinteractive interface of DFSMS that allows users andstorage administrators access to the storagemanagement functions.interval migration. In DFSMShsm, automaticmigration that occurs when a threshold level ofoccupancy is reached or exceeded on aDFSMShsm-managed volume, during a specified timeinterval. Data sets are moved from the volume, largesteligible data set first, until the low threshold ofoccupancy is reached.ISMF.ISPF.KKEK.See Interactive Storage Management Facility.See Interactive System Productivity Facility.See key-encrypting keykey. One or more characters within an item of datathat are used to identify it or control its use. As used inthis publication, one or more consecutive characterstaken from a data record, used to identify the recordand establish its order with respect to other records.See also prime key.key sequence. The collating sequence of data records,determined by the value of the key field in each of thedata records. It can be the same as, or different from,the entry sequence of the records.key-sequenced data set (KSDS). A VSAM data setwhose records are loaded in key sequence andcontrolled by an index. Records are retrieved andstored by keyed access or by addressed access, andnew records are inserted in the data set in keysequence because of free space allocated in the data set.Relative byte addresses of records can change becauseof control interval or control area splits.KSDS.LLDS.See key-sequence data setSee linear data setlevel 0 volume. A primary volume or a user volumenot managed by DFSMShsm.level 1 volume. A volume owned by DFSMShsmcontaining data sets that migrated from a level 0volume.level 2 volume. A volume under control ofDFSMShsm containing data sets that migrated from alevel 1 volume, or from a volume not managed byDFSMShsm.library. A partitioned data set containing a relatedcollection of named members.linear data set (LDS). A VSAM data set that containsdata but no control information. A linear data set canbe accessed as a byte-addressable string in virtualstorage.LRECL.MLogical record lengthmanagement class. A collection of managementattributes, defined by the storage administrator, used tocontrol the release of allocated but unused space; tocontrol the retention, migration, and back up of datasets; to control the retention and back up of aggregategroups, and to control the retention, back up, and classtransition of objects.master catalog. A catalog that contains extensive dataset and volume information that VSAM requires tolocate data sets, to allocate and deallocate storagespace, to verify the authorization of a program oroperator to gain access to a data set, and accumulateusage statistics for data sets.MCDS.MEDIA2.MEDIA3.MEDIA4.See Migration control data setEnhanced Capacity Cartridge System TapeHigh Performance Cartridge TapeExtended High Performance Cartridge Tapemigration. The process of moving unused data tolower cost storage in order to make space forhigh-availability data. If you wish to use the data set, itmust be recalled. See also migration level 1, migrationlevel 2.migration control data set (MCDS). In DFSMShsm, aVSAM key-sequenced data set that contains statisticsrecords, control records, user records, records for datasets that have migrated, and records for volumes undermigration control of DFSMShsm.migration level 1. DFSMShsm-owned DASD volumesthat contain data sets migrated from primary storagevolumes. The data can be compressed. See also storagehierarchy. Contrast with primary storage, migration level 2.migration level 2. DFSMShsm-owned tape or DASDvolumes that contain data sets migrated from primarystorage volumes or from migration level 1 volumes.The data can be compressed. See also storage hierarchy.Contrast with primary storage, migration level 1.Glossary 519