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RE: Sync Definition #2 (corrected)

From: David Orchard <dorchard@bea.com>
Date: Thu, 27 Feb 2003 08:41:40 -0800
To: <www-ws-arch@w3.org>
Message-ID: <008001c2de7f$1ae5dd00$770ba8c0@beasys.com>
RE: Sync Definition #2 (corrected)What classifies as "wait for a response"?
I typically think of a synchronous definition as "a programmatic flow of
control on the sender effectively does nothing but wait for a response after
sending it's request".  And before everybody goes gaga over showing edge
cases that are asynch that have flow of control, or multiple flows of
control that are synch, that's not the real issue.  The point is that
synchronicity typically has the notion of *something* blocking and waiting
for the response.

Another approach is to couple synchronicity with connections.  So
synchronous is where the request and response flow forwards and backwards
over the same virtual connection between the sender and receiver.  Of
course, it's possible to have synch interactions over non-synch connections,
which is why I think that synchronicity is more of a feature of program
logic than bits on the wire.

Hey look, textual suggestion and only 8 sentences of prose.

Cheers,
Dave
  -----Original Message-----
  From: www-ws-arch-request@w3.org [mailto:www-ws-arch-request@w3.org]On
Behalf Of Assaf Arkin
  Sent: Wednesday, February 26, 2003 10:42 PM
  To: Walden Mathews; Ugo Corda; www-ws-arch@w3.org
  Subject: RE: Sync Definition #2 (corrected)


  I just love permutations ;-)

  Seriously. In order to say that something is synchronous you need to say
what it is that's synchronous.

  The definition given below only describes a synchronous (request/response)
operation but doesn't describe an asynchronous (input-only or output-only)
operation, so it's only half way there. We still need to describe
asynchronous operations.

  And it describes the operation based on how the protocol works, which is
interesting and important, but still says nothing about the operation
itself.

  arkin

   -----Original Message-----
  From: Walden Mathews [mailto:waldenm@optonline.net]
  Sent: Wednesday, February 26, 2003 7:29 PM
  To: Assaf Arkin; Ugo Corda; www-ws-arch@w3.org
  Subject: Re: Sync Definition #2 (corrected)


    Arkin,

    I don't understand where your fascination with these permutations
    is coming from.  I thought the goal was to define the two terms, one
    definition each, and let it go at that (if possible).

    Walden
      ----- Original Message -----
      From: Assaf Arkin
      To: Ugo Corda ; www-ws-arch@w3.org
      Sent: Wednesday, February 26, 2003 3:51 PM
      Subject: RE: Sync Definition #2 (corrected)


      Actually, yours can be easily phrased in terms of mine:

      A synchronous interaction (= reqeust/response) is communicated
asynchronously when the request and response are chronologically decoupled.
In other words ...

      A synchronous interaction is communicated synchronoulsy if the reverse
could be said.

      Which of course begs the question, what about an asynchronous
interaction. Say I just send a message but don't expect a response?

      An asynchronous interaction (= send or receive) is communicated
asynchronoulsy when the sender does not have to wait for the receiver to
receive the message.

      An asynchronous interaction is communicated synchronoulsy if the
reverse could be said.

      arkin
        -----Original Message-----
        From: Ugo Corda [mailto:UCorda@SeeBeyond.com]
        Sent: Wednesday, February 26, 2003 12:46 PM
        To: Assaf Arkin; www-ws-arch@w3.org
        Subject: RE: Sync Definition #2 (corrected)


        Well, it's a matter of definitions, and evidently yours does not
correspond to mine. I hope people will vote soon so that we can put this
issue behind ...

        Ugo
          -----Original Message-----
          From: Assaf Arkin [mailto:arkin@intalio.com]
          Sent: Wednesday, February 26, 2003 12:15 PM
          To: Ugo Corda; www-ws-arch@w3.org
          Subject: RE: Sync Definition #2 (corrected)


          I think you have just defined a synchronous interaction
(request/response, see formal definition) in terms of an asynchronous
transport (i.e. one that does send and receive actions independently).

          arkin
            -----Original Message-----
            From: www-ws-arch-request@w3.org
[mailto:www-ws-arch-request@w3.org]On Behalf Of Ugo Corda
            Sent: Wednesday, February 26, 2003 7:36 AM
            To: Ugo Corda; www-ws-arch@w3.org
            Subject: RE: Sync Definition #2 (corrected)


            Asynchronous:
            A request/response interaction is said to be asynchronous when
the request and response are chronologically decoupled. In other words, the
client agent does not have to "wait" for the response once it issues the
initial request. The exact meaning of "not having to wait" depends on the
characteristics of the client agent (including the transfer protocol it
uses). Examples include receiving the response on a different thread, on a
different socket, on a different end-point, by polling the server, etc.

            Synchronous:
            The opposite of asynchronous.
Received on Thursday, 27 February 2003 11:44:47 GMT

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