Execute Direct Access Program: Difference between revisions

Revision as of 16:18, 8 May 2011

Revision as of 22:35, 8 May 2011

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In [[IBM mainframe]] [[operating system]]s, '''Execute Direct Access Program''' ('''XDAP''') is a pseudo access method for accessing direct access datasets on a record by record basis.

Existing records may be read or updated. The dataset may not be created nor extended using XDAP; for that purpose BDAMBSAM or BPAM is required. XDAP may coexist with BDAMBSAM or BPAM, and several OS components are implemented in this way.

The programmer is responsible for computing the full direct access record identifier, MBBCCHHR. System algorithms are available for calculating the MBBRRHHR from a TTRN. Additional system algorithms are available for calculating the TTRN from a record number.