Is it possible to implement either a reliable or an unreliable (process) failure detector using an unreliable communication channel?
What will be an ideal response?
An unreliable failure detector can be constructed from an unreliable channel – all that changes from use of a reliable channel is that dropped messages may increase the number of false suspicions of process failure.
A reliable failure detector requires a synchronous system. It cannot be built on an unreliable channel since a dropped message and a failed process cannot be distinguished – unless the unreliability of the channel can be masked while providing a guaranteed upper bound on message delivery times. A channel that dropped messages with some probability but, say, guaranteed that at least one message in a hundred was not dropped could, in principle, be used to create a reliable failure detector.
You might also like to view...
Write down the three steps of the program development process and their purpose.
What will be an ideal response?
In many ways, the history of computers has followed a similar path to automobiles. At first, automobiles were curiosities, accessible to only a small portion of the population. This changed with the introduction of the Ford Model T in 1908 [Gross 1996]. Since then, automobile makers have continued to make improvements on cars. Compare some of the differences between a Model T and today’s cars in terms of the HCI goals of safety, usability and appeal.
What will be an ideal response?
A ____ shows or hides portions of a layer and can protect areas of the layer from inadvertent editing.
a. shape b. locked area c. shadow d. mask
The ________ checks a workbook for personal data.
Fill in the blank(s) with the appropriate word(s).