From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: * X-Spam-Status: No, score=1.1 required=5.0 tests=BAYES_40,INVALID_DATE autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 1014db,ef0074ec236ba6e3 X-Google-Attributes: gid1014db,public X-Google-Thread: 109fba,ef0074ec236ba6e3 X-Google-Attributes: gid109fba,public X-Google-Thread: 1108a1,ef0074ec236ba6e3 X-Google-Attributes: gid1108a1,public X-Google-Thread: 103376,b19fa62fdce575f9 X-Google-Attributes: gid103376,public X-Google-Thread: 108717,ef0074ec236ba6e3 X-Google-Attributes: gid108717,public X-Google-ArrivalTime: 1994-12-06 10:52:05 PST Path: bga.com!news.sprintlink.net!howland.reston.ans.net!news.moneng.mei.com!uwm.edu!lll-winken.llnl.gov!fnnews.fnal.gov!lakesis.fapesp.br!bee.uspnet.usp.br!carpa.ciagri.usp.br!srsigris From: srsigris@ciagri.usp.br (Sergio R. Sigrist) Newsgroups: comp.lang.ada,comp.lang.c,comp.programming,comp.lang.c++,comp.object Subject: Re: What is OO (Was Why don't large companies use Ada?) Date: 6 Dec 1994 17:06:37 GMT Organization: Universidade de Sao Paulo / Brasil Message-ID: <3c25mt$l8s@bee.uspnet.usp.br> References: <3aamuc$14l@matrix.fwi.uva.nl> <785104767snz@rippleco.demon.co.uk> <3b1r1s$lkk@whitbeck.ncl.ac.uk> NNTP-Posting-Host: carpa.ciagri.usp.br X-Newsreader: TIN [version 1.2 PL2] Xref: bga.com comp.lang.ada:8347 comp.lang.c:33574 comp.programming:5659 comp.lang.c++:39852 comp.object:9517 Date: 1994-12-06T17:06:37+00:00 List-Id: R. Kerr (R.Kerr@ncl.ac.uk) wrote: : Don Vick (dvick@lanier.com) wrote: : > I'm sure lots of people will have answers for this one. Here's a : > historical view (as best I can remember it). : > In the mid to late '70s, people who developed large complex software : > for a living were trying to find a good way to divide a large system : > into smaller pieces to make it more manageable and (theoretically) : > allow the coding to be done by teams instead of individuals. Lots of : > people had theories on ways to divide, or decompose a system. : > Ken Orr said, "Make the program structure like the output structure." : > Michael Jackson (the computer scientist, not the singer) said, "Make the : > program structure like the input data structure." : > Glen Myers said, "Make the program structure like the functional structure : > of the application." : > Others (I've forgotten who said what) looked at data flow or process : > structure in different ways to get clues on decomposition criteria. : > And someone said, "Think of the objects that the application models; : > identify the data (what we know about the objects) and the operations : > (what we do to the objects), and make *that* your program structure. : > This turned out to be a pretty good way to do things - programs could become : > more maintainable and understandable, and it was easy to hand out objects : > to different programmers for implementation, as long as they implemented : > the agreed-upon operations for their object. : > ..................... : > In other words, "object oriented" was first of all a decomposition strategy, : > and only incidentally a kind of language, or database, or design methodology. : > Anyway, that's the way I remember it. : That's not quite the way it was. The fundamental concepts were developed : in the discrete event simulation context for the purpose of mastering the : inherent complexity in modelling dynamic systems. The physical and : conceptual decomposition techniques supported by these concepts were : recognised to be equally relevant in the software architecture scene : generally. : This all happened in the 1960s but it took rather a long time for the rest : of the world to catch on and, in many cases, they still haven't. The term : "object-oriented" had not been coined at that time but those of us : involved in this work did use the word "object" in exactly the way it is : used now. : Detailed accounts of these developments can be read in: : "The Development of the SIMULA Languages", K. Nygaard & O-J-Dahl, : Academic Press, New York, 1981. : and : "Compiling SIMULA: A Historical Study of Technological Genesis", : Jan Rune Holmevik, IEEE Annals of the History of Computing, : vol.16, no. 4, 1994. : These papers give an all-round account of the conception, gestation and : birth pangs of the OOP paradigm. (For those who may be unaware of this, : everything object-oriented is derived from SIMULA in some sense. Even : now, those wishing to get a sound grasp of OOP principles could do a lot : worse than have a look at SIMULA which still has a few notions not yet : adopted generally.) : Cheers....Ron : ------------------------------------------------------------------------ : Ron Kerr, Computing Service, Newcastle University, NE1 7RU, England. : Tel. +44 191 222 8187 Fax. +44 191 222 8765 (NOTE new area code) : ------------------------------------------------------------------------