IBM Systems Application Architecture: Difference between revisions

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Revision as of 16:06, 30 December 2014

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'''Systems Application Architecture''' ('''SAA''') is a set of standards for [[computer software]] developed by [[IBM]]. The SAA initiative was started in 1987 under the leadership of [[Earl Wheeler]], the "Father of SAA".<ref>{{cite news|last1=Bride|first1=Ed|last2=Desmond|first2=John|title=Wheeler: father of SAA - IBM VP and General manager of programming Systems Division Earl Wheeler; Systems Application Architecture - interview|url=http://findarticles.com/p/articles/mi_m0SMG/is_n15_v9/ai_8048960/|accessdate=June 20, 2012|newspaper=Software Magazine|date=Dec 1989}}</ref> The intent was to implement SAA in IBM [[operating system]]s including [[MVS]], [[OS/400]] and [[OS/2]]. [[IBM AIX|AIX]], IBM's version of the [[UNIX]] operating system, was not a target of SAA, but does have interoperability with the SAA family.

SAA did not define new standards, but selected from among IBM's existing guidelines and software. IBM also purchased some third party software from developers such as [[Bachman Information Systems]], Index Technology, Inc., and [[KnowledgeWare|KnowledgeWare, Inc.]].<ref>{{cite news|title=IBM kauft sich für SAA Software-Know-how ein|url=http://www.computerwoche.de/heftarchiv/1989/35/1151816/|accessdate=June 21, 2012|newspaper=Computerwoche|date=1989-08-25}}</ref> These were intended to be implemented uniformly across all SAA compliant environments.

The standard was "designed to make application programs look and work in the same manner across the entire range of the company's personal computing systems, midrange processors and System/370 processors.".<ref>{{cite web|last=IBM Corporation|title=IBM Archives: 1987|url=http://www-03.ibm.com/ibm/history/history/year_1987.html}}</ref>

SAA was labeled "complex, obscure, and potentially difficult to learn."<ref name=Linnell>{{cite book|last=Linnell|first=Dennis|title=The SAA Handbook|year=1990|publisher=Addison-Wesley|isbn=0-201-51786-8|url=http://books.google.com/books/about/The_SAA_handbook.html?id=ZVkPAQAAMAAJ}}</ref>{{rp|p.xi}}

Under [[Louis V. Gerstner, Jr.|Lou Gerstner]] IBM later quietly discontinued use of the "SAA" [[Umbrella term|umbrella]]. By 2001, SAA was being spoken of in the past tense.<ref>{{cite news|last=Cooper|first=Charles|title=Gerstner's legacy and why it matters|url=http://www.zdnetasia.com/gerstners-legacy-and-why-it-matters-38030327.htm|accessdate=June 20, 2012|newspaper=ZDNet|date=November 2, 2001}}</ref> However many of the individual components of SAA are still in use {{as of |2014|lc=y}}.

==Common programming interface (CPI)==

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CPI included a number of pieces:<ref name=Linnell />{{rp|pp.46–51}}

* Programming languages &mdash; [[PL/I]], [[COBOL]], [[Fortran]], [[C (programming language)|C]], [[IBM RPG|RPG]] and [[REXX]].

* Application generator &mdash; [[IBM Cross System Product (CSP)]].

* Database access &mdash; [[IBM SQL/DS|SQL]].

* Query interface &mdash; [[IBM Query Management Facility|QMF]].

* Presentation interface &mdash; the OS/2 [[Presentation Manager]] was a full implementation of the SAA presentation interface. [[IBM Graphical Data Display Manager (GDDM)]] provided compatible SAA graphics support for MVS and VM.

* Dialog interface &mdash; [[ISPF]] represented the text mode dialog interface; OS/2 represented the full graphical interface.

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'''Common User Access''' aimed at providing "a common user interface for the entire IBM product line. A user who sits down at a PC should see the same menus, keyboards and procedures that he would at a 3270 terminal."<ref name=Perna/>

Because of hardware differences complete commonality was impossible to attain. IBM created two CUA standards, the ''Basic Interface'' for [[IBM 3270]] and [[IBM 5250]] terminals, and the ''Advanced Interface'' for so-called "intelligent workstations", or PCs. The keyboard was standardized to the [[IBM PC keyboard#Keyboard layouts|"AT Enhanced" keyboard layout]] .<ref name=Linnell />{{rp|pp.39–40}}

==Common communications services (CCS)==

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Three types of data links were supported:<ref name=Linnell />{{rp|pp.56–58}}

* [[Synchronous Data Link Control]] (SDLC) high speed [[wide area network]]s.

* [[X.25]] packet-switched networks.

* [[Token ring]] [[local area network]]s (LAN).

'''Application Services'''<ref name=Linnell />{{rp|pp.58–59}} were provided by:

* CCS supported [[IBM 3270]] data streams, mainly for existing devices,

* [[Document Content Architecture]] specified a format for documents to be exchanged among different word processors and other software.

* [[IBM Intelligent Printer Data Stream (IPDS)|Intelligent Printer Data Stream (IPDS)]] was a page description language like Xerox [[Interpress]] or Adobe [[PostScript]].

* [[Snads|SNA Distribution Services (SNADS)]] for [[store and forward]] document transmission,

* Document Interchange Architecture (DIA) for electronic mail,

* [[IBM Distributed Data Management Architecture]] (DDM)for file sharing.

* [[DRDA|Distributed Relational Database Architecture]] (DRDA) for sharing relational databases.

==Common applications==

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==References==

{{Reflist}}

==Further reading==

* {{cite book|last=Grochow|first=Jerrold M.|title=SAA: a guide to implementing IBM's systems application architecture|year=1991|publisher=Yourdon Press|isbn=9780137857593|url=http://books.google.com/books/about/SAA.html?id=vu1QAAAAMAAJ}}