اسئلة الواجب الثالث :
Q1 : Explain the following
Boot control block-
Volume control block-
File control block-
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Q2 : Suppose that a disk drive has 100 cylinders, numbered 0 to 99
The driver is currently serving a request at cylinder 14.
The queue of pending requests is, in the order received: 1, 12, 9, 80, 81, 1, 82, 10, 42
Starting from the current head position, what is the total distance (in cylinders) that
the disk arm moves to satisfy all the pending requests for the following scheduling algorithms.
1- First come first serve
2- (SCAN (initially moving downwards
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Q3 : What is thrashing? What causes thrashing and how to prevent it
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Q4 : Consider the following page reference string :
4 - 5 - 2 - 1 - 6 - 5 - 4 - 4 - 1 - 2 - 1
Assume we have four frames that are initially empty, and FIFO page-replacement is used.
Show the frames content after every reference.
Also specify the faults that occurred, and the fault rate. Start with empty frames like the following:
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