Section 6.1. refers to systems that are space-coupled but time- uncoupled – that is, messages are
directed towards a given receiver (or receivers), but that receiver can have a lifetime independent
from the sender’s. Can you construct a communication paradigm with these properties? For
example, does email fall into this category?

What will be an ideal response?


This is a subtle point and we invite the reader to dwell on this themselves. Is there a communication paradigm
whereby a message is directed towards a given named receiver with known identity and hence bound in space,
but where the sender and recipient have different lifetimes? This partially depends on the interpretation of
different lifetimes, that is whether this implies the receiver may not exist yet or whether the receiver does exist
but is not available at a given time to receive a message. If we take the first interpretation, we can think of a
non-computer example, that is a letter addressed to a yet unborn great-grandchild. We can also think about
time capsules addressed to a given recipient. If we take the second interpretation, then email does fit this
category, that is a mail message is directed towards a known receiver who may or may not be around at a given
time but who will receive the message when next connected (see also Exercise 6.4. below). Note that this
assumes that we are focusing on the delivery of the message to the intended person rather than their mailbox.

Computer Science & Information Technology

You might also like to view...

Which of the following is false?

a. Since BigInteger is not a primitive type, we can’t use the arithmetic, relational and equality operators with BigIntegers. b. BigInteger method compareTo compares the BigInteger number that calls the method to the method’s BigInteger argument, and returns -1 if the BigInteger that calls the method is less than the argument, 0 if they’re equal or 1 if the BigInteger that calls the method is greater than the argument. c. The value 1 can be implicitly converted to a BigInteger. d. BigInteger can represent integer values larger than what primitive type long can represent.

Computer Science & Information Technology

How many devices can a single USB host controller theoretically support?

A. 63 B. 127 C. 255 D. 256

Computer Science & Information Technology

A popular technique for investigating causes and effects is called a _____ diagram.

A. causebone B. fishbone C. jawbone D. crossbone

Computer Science & Information Technology

A class method is defined as ______.

a) static b) abstract c) private d) protected

Computer Science & Information Technology