Problem 39
Why is disabling the interrupts in a multicore operating system not considered to be an efficient approach?
Problem 40
A process that is waiting for a time slice is said to suffer starvation if it is never given a time slice. a. The pavement in the middle of an intersection can be considered as a nonshareable resource for which cars approaching the intersection compete. A traffic light rather than an operating system is used to control the allocation of the resource. If the light is able to sense the amount of traffic arriving from each direction and is programmed to give the green light to the heavier traffic, the lighter traffic might suffer from starvation. How is starvation avoided? b. In what sense can a process starve if the dispatcher always assigns time slices according to a priority system in which the priority of each process remains fixed? (Hint: What is the priority of the process that just completed its time slice in comparison to the processes that are waiting, and consequently, which routine gets the next time slice?) How, would you guess, do many operating systems avoid this problem?
Problem 43
What problem arises as the lengths of the time slices in a multiprogramming system are made shorter and shorter? What about as they become longer and longer?
Problem 44
When is it preferable to use the deadlock prevention scheme, the deadlock avoidance scheme, and the deadlock detection and recovery scheme?
Problem 45
Identify two activities that can be performed by an operating system's administrator but not by a typical user.
Problem 47
Suppose a password consisted of a string of nine characters from the English alphabet (twenty-six characters). If each possible password could be tested in a millisecond, how long would it take to test all possible passwords?
Problem 48
Why are CPUs that are designed for multitasking operating systems capable of operating at different privilege levels?
Problem 50
Identify three ways in which a process could challenge the security of a computer system if not prevented from doing so by the operating system.
Problem 51
What are the conditions that lead to a deadlock?
