& XSLT >  the term simply means that a common clock between transmitters/receivers is
not
>  required for communication.

Communications have evolved since we discussed synch/asynch communications in
the context of Bisync, SDLC, UARTs, ISRs, and COM ports.  Distributed computing
has introduced other use cases and issues. For example, Internet computing
involves multiple time zones and potentially long response times. Blocking i/o
(e.g., page lock) isn't practical.

In a distributed computing environment, we're discussing synchronous
communication
when we talk about request-response protocols with sockets, active connections
and threads, online servers. Also web conferencing, live chat, and (live)
webcasts.

If we're talking message queues, fire-and-forget messaging, store-and-forward,
callbacks, streaming video, transient server connections and so on, that's
asynchronous communication (in the distributed computing context).

"The Medium Is the Message" discusses messaging middleware:
http://www.intelligententerprise.com/010507/feat1_1.jhtml

"XML Messaging"
http://www.javaworld.com/javaworld/jw-03-2001/jw-0302-xmlmessaging.html



======== Ken North ===========
www.WebServicesSummit.com
www.SQLSummit.com
www.GridSummit.com


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