Virtual Storage Access Method


Virtual Sequential Access Method


(VSAM) An IBM disk file storage scheme first used in S/370 and virtual storage. VSAM comprises three access methods: Keyed Sequenced Data Set (KSDS), Relative Record Data Set (RRDS), and Entry Sequenced Data Set (ESDS).

Both IMS/DB and DB2 are implemented on top of VSAM and use its underlying data structures.

["Storage" or "Sequential"?]