ANSWER

Let’s go through each of the questions one by one:

Q 3.2:

• At time 22, P3 is in the Running state because it executed a read command from disk unit 2.
• At time 37, P5 is in the Blocked state, and it’s blocked on the completion of its write operation to disk unit 3.
• At time 47, P5 is in the Running state because it was swapped back in.

Q 3.4: Unfortunately, I cannot draw diagrams, but I can describe how to create a queuing diagram for the seven-state process model in Figure 3.9b. You’ll have seven states: Running, Ready, Blocked, New, Exit, Zombie, and Suspended.

Q 4.4: In a model where there is a one-to-one mapping between user-level threads and kernel-level threads, if one thread within a process issues a blocking system call, other threads within the same process can continue to run. This can make multithreaded programs run faster than their single-threaded counterparts on a uniprocessor computer because other threads can continue to perform useful work while one thread is blocked. In a single-threaded program, a blocking system call would halt the entire program until the call completes, whereas in a multithreaded program, other threads can make progress.

Q 4.5: When a process exits and there are still threads of that process running, the behavior depends on the operating system and how threads are managed. In some systems, the remaining threads may be terminated automatically when the process exits, while in others, they may continue to run. It ultimately depends on the thread management policy of the specific operating system.

Q 6.5: a. To verify the Available array, you can use the formula: Available = (Available) – (Current Allocation). In this case, it would be: (6, 3, 5, 4) – (8, 2, 3, 4) = (-2, 1, 2, 0). The negative values in the Available array indicate that there are not enough resources available to satisfy any process.

b. To calculate the Need matrix, you subtract the Current Allocation from the Maximum Demand for each process.

c. To show that the current state is safe, you can use the Banker’s algorithm to find a safe sequence of processes. Unfortunately, it’s too complex to demonstrate here, but you can follow the steps of the Banker’s algorithm to find a safe sequence.

d. To determine if the request (3, 2, 3, 3) from Process P5 should be granted, you can use the Banker’s algorithm to check if it’s safe to allocate these resources. Again, this involves several steps, and the request can be granted if it doesn’t lead to an unsafe state.

Q 6.11: a. To determine if the fourth process with a maximum memory need of 60 and an initial need of 25 units can be granted, you can use the Banker’s algorithm. Unfortunately, it’s too complex to demonstrate here, but you can follow the steps of the Banker’s algorithm to check for safety.

b. To determine if the fourth process with a maximum memory need of 60 and an initial need of 35 units can be granted, again, you would use the Banker’s algorithm to check for safety.

Q 6.15: To find the minimum number of units of the resource needed to be available for this state to be safe, you can use the Banker’s algorithm. The Banker’s algorithm checks for safety by simulating resource allocation. If a sequence of resource requests and releases can be found that avoids deadlock, the state is considered safe. The minimum number of units needed to be available is the maximum initial claim of any process minus the sum of the resources already allocated, which in this case is 3 (max claim) – 1 – 1 – 3 – 2 = -4. However, you can’t have a negative number of units available, so the minimum number needed for safety would be 0 units.

QUESTION

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