View source for Template:Mainframe I/O access methods

{{Navbox
|name      = Mainframe I/O access methods
|state     = {{{state|uncollapsed}}}
|title     = [[OS/360 and successors]] I/O [[access method]]s
|listclass = hlist

|group1    = Low-level
|list1     =
* [[Execute Channel Program|EXCP]] 
* [[Execute Channel Program in Real Storage|EXCPVR]] 
* [[Start Input/Output|STARTIO]]
|group2    = Storage
|list2     =
* [[Execute Direct Access Program|XDAP]] 
* [[Basic Direct Access Method|BDAM]] 
* [[Basic Sequential Access Method|BSAM]] 
* [[Queued Sequential Access Method|QSAM]] 
* [[Basic Partitioned Access Method|BPAM]]
* [[Indexed Sequential Access Method|ISAM]] 
* [[Virtual Storage Access Method|VSAM]] 
* [[Object Access Method|OAM]]
|group3    = Network
|list3     =
* [[Basic Telecommunications Access Method|BTAM]] 
* [[Queued Teleprocessing Access Method|QTAM]] 
* [[Telecommunications Access Method|TCAM]] 
* [[Virtual Telecommunications Access Method|VTAM]]

}}<noinclude>

== Usage ==
This template is to be used at the top of an article source code: To appear on the right top.

== All the previous article like texts ==
''cleanup: This is not an article! All the article-like stuff is to be moved, i.e. to the [[Access method]] article: All the intro paragraphs as well as all the latter chapters.''

The '''OS/360 and successors I/O access methods''' are programming [[Application programming interface|API]]s on the [[OS/360]] [[mainframe computer]] [[operating system]] and its [[OS/360 and successors|successors]], such as [[OS/VS1]], [[OS/VS2 (SVS)]], [[MVS]], [[OS/390]], and [[z/OS]], used by programmers to implement input/output operations on [[Data set (IBM mainframe)|data sets]] (files) and [[telecommunications network]]s. They are by convention referenced to with ''...AM'' acronyms, standing for ''... Access Method''.

== Including EXCP, EXCPVR and STARTIO in a separate class ==
These are general purpose, low-level I/O device methods of access, and not "access methods" in the conventional use of this term.

In pre-MVS instances of the OS, EXCP was the lowest level method of access, and all access methods utilized EXCP.

In SVS, EXCPVR was added to enable programs which were executing in real storage to avoid much of the overhead of EXCP. This was continued in MVS.

In MVS and later instances of the OS, STARTIO replaced both forms of EXCP as the lowest level method of access. The so-called virtual access methods utilize STARTIO directly, or they have their own SVC which, in turn, utilizes STARTIO. The legacy access methods also utilize STARTIO, but go through EXCP to do so.

== See also ==
* [[Access method]]
* [[Data set (IBM mainframe)]]
* {{Tl|operating-system-stub}}
* {{Tl|mainframe-compu-stub}}

== External references ==
# [http://researchweb.watson.ibm.com/journal/rd/255/auslander.pdf History of IBM mainframes]
# [http://www.redbooks.ibm.com/redbooks/pdfs/sg246983.pdf IBM Redbook for system programmers]


[[Category:Computer hardware navigational boxes]]

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