Access method: Difference between revisions

Revision as of 08:06, 9 March 2013

Revision as of 12:37, 14 March 2013

Line 1:

{{refimprove|date=August 2012}}

{{Mainframe I/O access methods}}

An '''access method''' is a function of a [[mainframe computer|mainframe]] [[operating system]] that enables access to data on disk, tape or other external devices. They were introduced in 1963 in IBM [[OS/360]] operating system.<ref name=aus>[http://researchweb.watson.ibm.com/journal/rd/255/auslander.pdf M. A. Auslander, D. C. Larkin, A. L. Scherr: "The Evolution of the MVS Operating System", pages 478-479]</ref> Access methods provide an [[API]] for programmers to transfer data to or from device, and could be compared to [[device driver]]s in non-mainframe operating systems.

Line 34 ⟶ 33:

* [[VTAM]] - [[Virtual telecommunications access method]]

== IMS ==

The [[IBM Information Management System]] (IMS) uses the term "access method" to refer to its methods for manipulating "segments in a database record." These are: Generalized Sequential Access Method (GSAM), Hierarchical Direct Access Method (HDAM), Hierarchical Indexed Direct Access Method (HIDAM), Hierarchical Indexed Sequential Access Method (HISAM), Hierarchical Sequential Access Method (HSAM), Partitioned Hierarchical Direct Access Method (PHDAM), Partitioned Hierarchical Indexed Direct Access Method (PHIDAM), Partitioned Secondary Index (PSIMDEX), Simple Hierarchical Sequential Access Method (SHSAM), and Simple Hierarchical Indexed Sequential Access Method (SHISAM).<ref>{{cite web|last=IBM Corporation|title=Types of IMS databases|url=http://publib.boulder.ibm.com/infocenter/dzichelp/v2r2/index.jsp?topic=%2Fcom.ibm.ims11.doc.dag%2Fims_dbtypes.htm|accessdate=September 4, 2011}}</ref> This is a different use of the term from the other access methods mentioned in this article.

Line 44 ⟶ 43:

== References ==

{{Reflist}}

{{Mainframe I/O access methods}}

[[Category:IBM mainframe operating systems]]