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 Sequential 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.

(1999-01-18)