Nt1310 Unit 4

Words: 1265
Pages: 6

1. Describe the heuristic used in menu option 1.
Option 1, FIFO (first-in, first-out) implements the idea that the page that was the earliest to be entered into the buffer is least likely to be needed again. As a result, when the buffer is full, and a new page needs to be added, the page that has been in the buffer the longest is dropped and the new page is added.
2. Under what condition will this heuristic not be efficient? In this context an efficient buffer, is one that has the highest potential to provide a block of data out of the buffer and not have to go back to disk. In your answer consider whether this heuristic is the most effective approach is the value 5 is used more frequently than any other value.
Not to be flippant, but the heuristic is not efficient when the
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What happens when no integer is repeated in the input page values?
When no integer is repeated the most recently added page, in this case represented by an integer, is dropped over and over again as all of the pages in the buffer have the same recorded number of accesses. This eventually leads to a page, or potentially several pages if the buffer is larger, remaining in the buffer for an extended period of time without ever being used again. Functionally, this would become less efficient than just accessing information directly from the disk because it makes the buffer a useless intermediary.
3. Describe what happens in the buffer pool when a value is repeated in the page values.
If the value, or page, is still currently in the buffer the list counting page access increments by one. This increases the likelihood that it will be staying in the buffer longer each time it is accessed. If the value was not in the buffer despite being a repeat the least frequently used or in the case of a tie the most recently added will be dropped from the buffer. The repeated value will then be added and logged as having only been accessed once for the “frequency-of-use” table.

An additional