Any operation that can send data will be referred to as a sending operation; those that can receive will be referred to as receiving ones.
In order to investigate the benefits of asynchronous message exchange (fire-and-forget messaging) and queuing, CMQ itself was allowed to use asynchronous non-blocking send operations (which means CMQ was allowed to send the next message before a reply to the previous message had been received) similar to the IMB ping ping test.
Although this is not directly addressed in CMQ, there are two interesting aspects worth noticing: first, system calls are expensive and thus the number of send operations (which are systems calls) should be kept to a minimum; secondly, copying data, even in user space without involvement of system calls, is also far from optimal.
Furthermore, the send operation has been modified to let the sender check whether the send could proceed or not (e.g., when the channel was closed).
In situations however wherein the destination is also another mote powered by energy harvesting (duty cycling using LPL) the packet send operation would consume significantly more energy since the sender has to wait for the receiver to wake up, all the time keeping the radio on and drawing a high amount of current.
Typically, tasks exchange data by sending and receiving messages but data transfer usually requires cooperation among processors, that is, a "send" operation must have a matching "receive" operation.
Since the Sept. 11, 2001, attacks, the Pentagon has used broad interpretations of its authorities to expand military intelligence operations, including sending Special Operations troops on clandestine missions far from declared war zones.
For communication, we propose to decompose any data transfer between two operations A and B in three parts: a sending part where the sending operation is busy, a transit part where the data are routed and a receiving part, where the receiving operation is busy.
Within the government, advocates of the ground raids have argued that only by sending Special Operations forces into Pakistan can the United States successfully capture suspected operatives and interrogate them for information about top Qaeda leaders.
The Pentagon has also sharply expanded its intelligence work outside of war zones, sending Special Operations troops to embassies to gather information about militant networks.
