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Straw poll on "synchronous" definitions

From: David Booth <dbooth@w3.org>
Date: Tue, 11 Mar 2003 11:22:39 -0500
Message-Id: <5.1.0.14.2.20030311110541.02d7a650@localhost>
To: www-ws-arch@w3.org

At the end of our F2F meeting, I took an action to poll the working group
on the many "synchronous" definitions that were proposed.
This poll is not intended to decide on the definition of "synchronous"
directly, but only to narrow the field.  Once we have narrowed the field,
I will try to make adjustments as needed to reach consensus on a common
definition.


HOW TO VOTE
[Ballot form adapted from http://www.debian.org/vote/howto_vote ]

Erase everything above the top "-=-=-=-" line and erase everything
below the bottom "-=-=-=-" line.  Do not erase anything between these
lines.

Indicate your TOP THREE CHOICES.
In the brackets next to your most preferred choice, place a 1.  Place
a 2 in the brackets next to your next choice.  Continue till
you use 3 for your last choice.  Leave other choices
blank.  Start with 1, don't skip any numbers, don't repeat.

Then mail the ballot to: member-wsa-ballots@w3.org .  DO NOT SEND YOUR
BALLOT TO THE PUBLIC LIST.  Just Replying to this
message should work, but check the "To:" line.  Don't worry about spacing
of the columns or any quote characters (">") that your reply inserts.

Ballots are due by the end of Thursday 13 March 2003.

-=-=-=-=-=- Don't Delete Anything Between These Lines =-=-=-=-=-=-=-=-
synchronous Ballot    <FB-sync> (Don't remove this marker)

[1-3]  Choice
-----------------------------------------------------------------------
[   ] geoff-1   (see definition below)
[   ] frank-1   (see definition below)
[   ] frank-2   (see definition below)
[   ] dbooth-2  (see definition below)
[   ] dbooth-1  (see definition below)
[   ] ugo-2c    (see definition below)
[   ] daveo-1   (see definition below)
[   ] daveo-2   (see definition below)
[   ] moberg-1  (see definition below)
[   ] assaf-3   (see definition below)
[   ] cutler-1  (see definition below)
[   ] ferris-1  (see definition below)
[   ] mikec-1   (see definition below)
[   ] walden-1  (see definition below)
[   ] assaf-1   (see definition below)
[   ] assaf-2   (see definition below)
-=-=-=-=-=- Don't Delete Anything Between These Lines =-=-=-=-=-=-=-=-

Anything else may be rejected by the vote counting program.
You should see your vote in 
http://lists.w3.org/Archives/Member/member-wsa-ballots/
Only one vote per person, no more than one vote per account.


##################################################################
#####################  Candidate Definitions #####################
##################################################################

Definition geoff-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Mar/0029.html
A message exchange pattern (MEP) is a formal description of how messages
are exchanged between two or more parties in support of some application
purpose. The pattern may define a single message sequence, or may
correspond to a "family" of sequences by including repeated or nested
sequences. An MEP is synchronous if the specification of the message
sequence(s) includes elements in which the transmission of a message
is dependent on either (a) the reception of some other message(s), or
(b) coordination based on a common clock. An MEP is asynchronous if it
includes no such dependencies.

----
Definition frank-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Mar/0023.html
[From from Communicating Sequential Processes] Synchronous A rendezvous
of two activities is synchronous if they complete simultaneously.

----
Definition frank-2
http://lists.w3.org/Archives/Public/www-ws-arch/2003Mar/0023.html
Synchronous activity An activity involved in a synchronous rendezvous
may assume that the rendezvous is complete for both sides if it 's
side completes.

----
Definition dbooth-2
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0455.html
Synchronous interaction
An interaction is synchronous if the parties are involved in the
interaction at the same time and the interaction carries an expectation of
immediate processing.  A one-way interaction is synchronous if successful
message delivery implies that the message either has been processed by
the receiver or is actively being processed.  A round-trip or more complex
interaction is synchronous if the initiator pauses some of its processing
to wait for the interaction's constituent messages to be processed.
In a round-trip interaction, the request and response are often sent
over the same communication channel.

----
Definition dbooth-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0222.html
Property of an interaction whose results are directly following the
interaction. 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.

----
Definition ugo-2c
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0386.html
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.

----
Definition daveo-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0432.html
synchronous
a programmatic flow of control on the sender effectively does nothing but
wait for a response after sending it's request

----
Definition daveo-2
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0432.html
synchronous
the request and response flow forwards and backwards over the same
virtual connection between the sender and receiver.

----
Definition moberg-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0343.html
A web service response is said to be synchronous iff it is returned
using the same network connection used in sending the request to which
it is a response. (This implies that only one URL would be needed
for request-response MEP when the response is synchronous and uses a
transfer protocol that has URLs. It also implies that the request and
response occur within the interval of time that the network connection
exists. Also, there is overhead in setting up only one TCP connection
when TCP is used, and since we are talking about IP _connections_ that
will be almost always the case.)

A web service response is said to asynchronous iff it is returned using
a network connection that is distinct from that used for sending the
request to which it is a response. (Implications: Two URLs are needed to
configure a request-response MEP when the response is ==>asynchronous. The
response connection may occur while the request connection is still open
or after it is closed. For TCP-based transfer protocols, two connection
setups will be needed.)

----
Definition assaf-3
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0354.html
A transport is synchronous iff the request is returned using the same
network connection.

----
Definition cutler-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0358.html
Synchronous: a request/response exchange that is correlated by virtue of a
serialized, sequenced exchange of messages between requestor and
respondant, typically over the same socket or stream.

Asynchronous: a request/response exchange that is not synchronous,
typically relying on some mechanism such as Message-ID within the messages
to correlate the request and response messages.

----
Definition ferris-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0437.html
synchronous message exchange (applies to oneway as well as
request/response) requires that both sender and receiver, or initiator
and respondant, processes are running/active at the same time as the
exchange takes place. In the case of request/response, the exchange is
synchronous if both sender and receiver remain in the running/active
state for both the request and response.

asynchronous message exchange (also applies to oneway or request response)
does not require, but does not preclude, that both sender and receiver,
or initiator and respondant, processes are running/active at the same
time as the exchange takes place. It typcally requires some form of
mediation between the sender and receiver such as a message queue.

----
Definition mikec-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0318.html
(Taken from
http://whatis.techtarget.com/definition/0,,sid9_gci213080,00.html ?)
In program-to-program communication, synchronous communication requires
that each end of an exchange of communication respond in turn without
initiating a new communication. A typical activity that might use a
synchronous protocol would be a transmission of files from one point
to another. As each transmission is received, a response is returned
indicating success or the need to resend. Each successive transmission
of data requires a response to the previous transmission before a new
one can be initiated. Synchronous program communication is contrasted
with asynchronous program communication.

----
Definition walden-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0326.html
Synchronous, then, places a constraint on a response such that the response
must be received within a strictly or loosely defined time quantum (strict
vs lax synchrony), or else the exchange fails.
Asynchronous differs in that no amount of elapsed time signals the failure
of the exchange.

----
Definition assaf-1
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0321.html
An operation is synchronous if both service requester and service provider
engage will always engage in that operation at the same time.

----
Definition assaf-2
http://lists.w3.org/Archives/Public/www-ws-arch/2003Feb/0321.html
An interaction is synchronous if activities demarcated by that interaction
will always be performed at the same time.

[End]



-- 
David Booth
W3C Fellow / Hewlett-Packard
Telephone: +1.617.253.1273
Received on Tuesday, 11 March 2003 11:22:55 GMT

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