Virtual Storage Access Method: Difference between revisions

Revision as of 05:40, 5 May 2005

Revision as of 19:54, 24 May 2005

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'''Virtual SequentialStorage Access Method''' ('''VSAM''') is an [[IBM]] disk file storage scheme first used in the [[S/370]] and [[virtual storage]]. VSAM comprises three access methods: Keyed Sequential Data Set (KSDS), Relative Record Data Set (RRDS) and Entry Sequenced Data Set (ESDS). See [[record-oriented filesystem]].

''KSDS'' has indexes and data split into CI (Control Interval) in CA (Control Area) and multi index levelled. Forward and backward compression is applied to key values.