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RE: WSA constraints

From: Anne Thomas Manes <anne@manes.net>
Date: Mon, 23 Sep 2002 23:57:42 -0400
To: "Mark Baker" <distobj@acm.org>
Cc: <www-ws-arch@w3.org>, <mark.baker@sympatico.ca>
Message-ID: <ECEDLFLFGIEENIPIEJJPKEIMCHAA.anne@manes.net>

I don't know of a generic SOA definition that I can point you to. Certainly
OMG's OMA [1] defines an SOA. So does the Java RMI specification [2]. Once
upon a time I saw a similar specification for DCOM, but I can't find it now.
These are instances of an SOA, not a generic SOA. Those of us who have
worked with ONC, DCE, CORBA, DCOM, RMI, etc. for the last 10+ years just
grok it, because we've iterated through it 3 or 4 times before (but I doubt
that very many of us can articulate it). I think it's a really good exercise
to write it down.

The Web has many similarities to an SOA, but as I said, it's oriented for
human consumption rather than machine consumption. An SOA requires that a
service be defined by a contract. The Web has no such constraint. (HTTP GET
tells an application how to get a resource, but not how to use it once it
has it.) Web interactions are presumed to be stateless. SOA has no such
constraint. The Web requires that every resource has a URI. SOA has no such
constraint.

[1] http://www.omg.org/oma/
[2] http://java.sun.com/j2se/1.4/docs/guide/rmi/spec/rmiTOC.html

Anne

> But I'd like to ask you for a pointer to a
> definition of what a service oriented architecture is.  From what I can
> extract from the context in which the term is used, the Web already is
> an SOA.
>
> MB
> --
> Mark Baker, CTO, Idokorro Mobile (formerly Planetfred)
> Ottawa, Ontario, CANADA.               distobj@acm.org
> http://www.markbaker.ca        http://www.idokorro.com
>
Received on Monday, 23 September 2002 23:57:19 GMT

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