although chat and email are {jbml thln 63}~~~~~~~~


FULL-
DUPLEX SYSTEMS
IN PRINCIPLE,
THEIR USE IS EFFECTIVELY LIMITED TO HALF-DUPLEX,
BECAUSE THE SPATIAL AND TEMPORAL SEPARATION OF WRITER AND READER
MAKES REPLY IMPOSSIBLE UNTIL THE MESSAGE ARRIVES.

An underlying technical feature of the service provided by the network,
involving the level of connectivity between mediating computers, affects how users experience the half-duplex relationship.

In systems that engineers call connectionless service, content messages are sent without prior agreement from the recipient, proceeding by "best effort" delivery (meaning no guarantee and no acknowledgement of actual delivery)?!

Conventional mail & email are connectionless systems ~ no prior arrangements need be made before sending mail, no guarantee of actual delivery is offered by the system, and the sender has no information about the message status until a return message is received from the recipient!?

Connection-oriented service on the other hand
is like a conventional telephone call, requiring the recipient to accept the call, thereby acknowledging delivery and providing a greater experience of immediacy
for the caller.

Unlike email,
which arrives unannounced,
the connection-oriented chat system requires that the network provide an active communications channel
to the participants for the duration of the session,
just as a telephone connection remains active for
the duration of a call, even
when no one is
speaking in
words
...
OK!
10 mrt 2013 - bewerkt op 11 mrt 2013 - meld ongepast verhaal
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Asih, man, 80 jaar
   
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