Question

5.20 Which of the following scheduling algorithms could result in starvation? a. First-come, first-served b. Shortest job first c. Round robin d. Priority

Answer 1

Answer:

b. Shortest job first and d. Priority

Explanation:

First let us understand what starvation is. Starvation is basically situation in which a process does not get required resources because other processes are being allocated to these resources and are utilizing those resources. So that process is in starvation as it does not get access to the resource and it is unable to execute.

In the First-come first-served scheduling algorithm the processes are executed in the order or sequence such that the first process is executed first and the second process is executed after the first process finishes its execution. So in this scheduling algorithm no starvation can occur as there is no process which will never get a resource and will never be able to execute.

Shortest job first chooses out of the waiting processes, the process which has the shortest execution time to be executed first. This results in the processes with long execution time to wait for their execution. This wait can go till infinity and the waiting long processes might never get the resources for their execution if the shorter processes keep arriving. So this can result in starvation.

Round robin algorithm gives each process a fixed time slot called quantum time for its execution.  So no process will have to wait for long and wait for a resource to be allocated for long in order to be executed. So this is a starvation free scheduling algorithm.

In priority scheduling the processes are given priorities to execute which means that the process with high priority will be allocated the resource and will be executed first.  This causes the low priority processes to wait for long and this waiting can go to infinity and the low priority process might not be able to get a resource for their execution. So this scheduling algorithm could result in starvation.

Answer 2

Answer: (b) and (d)

Explanation:

Shortest job first and Priority are scheduling algorithms that could result in starvation.

The others won't result in starvation