COMP10052-AAAF-05-2010-for-viewing

Disconnect either process or both must use this

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Unformatted text preview: nec=on ­oriented (it need not be), the following opera=ons are also used:       Accept: the receiver process calls this opera=on to specify its readiness to engage in communica=on. Connect: the sender process call this opera=on to ini=ate the engagement. Disconnect: either process (or both) must use this opera=on to cleanly disengage. Calls Cause Interac=on Events All processes that want to communicate with another process must call such opera=ons in a predetermined order. Each such opera=on call causes an interac.on event to occur. For example:             A call to Send causes the event wherein the specified data is transmiVed to the specified process. A call to Receive causes the event wherein, upon the receipt of data (from the specified process, if this is s=pulated), that data is placed in the specified loca=on. It is crucial to remember, always, that calls are being made separately, independently, remotely, so that no communica=ng process is able to know what is going on in any other communica=ng process. Synchroniza=on/Blocking Primi=ves   The synchroniza=on and blocking proper=es of Send and Receive primi=ves specify when control returns to the invoking process and how acknowledgement of events in the callee is conveyed back to the caller.   There are four basic forms of Send and two basic forms of Receive. Basic Forms: Send (1)       Assume that a Send takes as a parameter the buffer in the sender process where the message to be sent is placed. Likewise, assume that a Receive takes as a parameter the buffer in the receiver process where the message to be received is placed. An asynchronous blocking Send does not return un=l the message has been copied out of the buffer in the sender process: it does not wait for acknowledgement by the (remote) receiver proce...
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This document was uploaded on 02/10/2014.

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