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RE: Snapshot of Web Services Glossary

From: Assaf Arkin <arkin@intalio.com>
Date: Fri, 21 Feb 2003 10:15:08 -0800
To: "Martin Chapman" <martin.chapman@oracle.com>, "'David Booth'" <dbooth@w3.org>, "'Hugo Haas'" <hugo@w3.org>, <www-ws-arch@w3.org>
Message-ID: <IGEJLEPAJBPHKACOOKHNAELIDDAA.arkin@intalio.com>

> please define "at the same time"

Linguistic:

synchronous - syn- same; similar; chronous - time

Simply saying something is synchronous means it occurs at the same time. The
trick here is two define the 'what'. For example, in synchronous
communication we say that send/receive occur at the same time, i.e. sender
knows when message has been received.

Formal:

Interaction is performed by two actors, initiator Ai and respondent Ar
Interaction involves two messages, request M1 and response M2
Actor Ai sends message M1 at time T1
Actor Ai receives message M2 at time T2
The interaction is performed by Ai bound by T1,T2
The interaction is performed by Ar bound by T1,T2
After actor Ai has completed the interaction successfully it can establish
the timeframe in which Ar has performed the interaction

arkin

>
> -----Original Message-----
> From: Assaf Arkin [mailto:arkin@intalio.com]
> Sent: Friday, February 21, 2003 9:49 AM
> To: Martin Chapman; 'David Booth'; 'Hugo Haas'; www-ws-arch@w3.org
> Subject: RE: Snapshot of Web Services Glossary
>
>
> > hmmm don't like the defn of synchronous:
> >
> >
> > >10.  synchronous
> > >[[
> > >Property of an interaction whose results are directly following the
> > >interaction. ]]
> > >I suggest adding:
> > >[[
> > >An interaction between an initiator and a respondent is
> > >synchronous if the
> > >initiator blocks some further processing while it waits for a
> > >corresponding
> > >action, response or acknowledgement from the respondent.
> > >]]
> >
> > who/what is doing the blocking? This makes no senese in  a context
> > where we don't talk about programming languages, middleware, OSs etc.
> > Properties of synchronous communications we can convey inthis space
> > are direct communication (i.e. not through store and forward) and the
> > fact that the reply (if any) comes back on the same communication
> > channel as the request.
>
> An operation involving an initiator and a respondent is
> synchronous if the operation involves the initiator and
> respondent at the same time.
>
> In other words, if I sends request to R (input of operation)
> and I receives response from R (output of same operation), I
> can tell when R performed the operation.
>
> I know of at least two client libraries in which the initiator
> application does not have to block waiting for the response.
> Although HTTP 1.1 will send the request and response on the
> same communication channel, other protocols may send the
> request and response on separate communication channels.
>
> arkin
>
> >
> > Martin.
>
Received on Friday, 21 February 2003 13:16:33 GMT

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