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

RRDS.SSCDS.SDSP.See relative record data setSee source control data setSee small data set packingscratch. The state of a tape volume which is availablefor general use. A scratch volume is requested byomitting the volume serial number.scratch tape.See scratch volume.scratch volume. A tape volume which has beenassigned the scratch use attribute by the software. If thecartridge resides in a 3495, it is assigned to the scratchcategory.secondary space allocation. Amount of additionalspace requested by the user for a data set whenprimary space is full. Contrast with primary spaceallocation.security.See data security.sequence set. The lowest level of the index of akey-sequenced data set; it gives the locations of thecontrol intervals in the data set and orders them by thekey sequence of the data records they contain. Thesequence set and the index set together comprise theindex.shelf. A place for storing removable media, such astape and optical volumes, when they are not beingwritten to or read.shelf location. (1) A single space on a shelf for storageof removable media. (2) In DFSMSrmm, a shelf locationis defined in the removable media library by a racknumber, and in a storage location, it is defined by a binnumber. See also rack number, bin number.shunt. The status of a unit of recovery that has failedat one of the following points:vvvWhile in-doubt during a two-phase commit processWhile attempting to commit changes to resources atthe end of the unit of recoveryWhile attempting to back out the unit of recoveryIf a unit of recovery fails for one of these reasons, it isremoved (shunted) from the primary system log to thesecondary system log pending recovery from thefailure.slot. A single cartridge storage location within a 3495.See also cell.small-data-set packing (SDSP). In DFSMShsm, theprocess used to migrate data sets that contain equal toor less than a specified amount of actual data. The datasets are written as one or more records into a VSAMdata set on a migration level 1 volume.small-data-set-packing data set. In DFSMShsm, aVSAM key-sequenced data set allocated on a migrationlevel 1 volume and containing small data sets that havebeen migrated.SMS.See storage management subsystemSMS class. A list of attributes that SMS applies todata sets having similar allocation (data class),performance (storage class), or backup and retention(management class) needs.SMS configuration. A configuration base, StorageManagement Subsystem class, group, library, and drivedefinitions, and ACS routines that the StorageManagement Subsystem uses to manage storage. Seealso configuration, base configuration, source control dataset .source control data set (SCDS). A VSAM linear dataset containing an SMS configuration. The SMSconfiguration in an SCDS can be changed and validatedusing ISMF. See also active control data set,communications data set.spanned record. A logical record whose lengthexceeds control interval length, and as a result crosses(or spans) one or more control interval boundarieswithin a single control area.sphere record. A collection of logically relatedsubrecords in one VSAM logical record.storage administrator. A person in the data processingcenter who is responsible for defining, implementing,and maintaining storage management policies.storage class. A collection of storage attributes thatidentify performance goals and availabilityrequirements, defined by the storage administrator,used to select a device that can meet those goals andrequirements.storage control. The component in a storagesubsystem that handles interaction between processorchannel and storage devices, runs channel commands,and controls storage devices.storage group. A collection of storage volumes andattributes, defined by the storage administrator. Thecollections can be a group of DASD volumes or tapevolumes, or a group of DASD, optical, or tape volumestreated as a single object storage hierarchy. See alsoVIO storage group, pool storage group, tape storage group,object storage group, object backup storage group, dummystorage group.storage hierarchy. An arrangement of storage deviceswith different speeds and capacities. The levels of thestorage hierarchy include main storage (memory, DASD522 z/OS V1R6.0 DFSMS Access Method Services for Catalogs