Question

Consider three CPU-intensive processes, which require 10, 20 and 30 time units and arrive at times 0,2 and 6 , respectively. How many context switches are needed if the operating system implements a shortest remaining time first scheduling algorithm? Do not count the context switches at time zero and at the end.

A. 1
B. 2
C. 3
D. 4

Answer 1

The number of context switches in this scenario is 2 (option B). In the shortest remaining time first (SRTF) scheduling algorithm, the number of context switches is determined based on the arrival times and CPU time required for each process.

Step-by-step explanation:

To determine the number of context switches needed if the operating system implements a shortest remaining time first (SRTF) scheduling algorithm, we need to consider the arrival times and CPU time required for each process.

According to the question, there are three processes with arrival times 0, 2, and 6, and CPU times of 10, 20, and 30 time units, respectively.

In the SRTF scheduling algorithm, the process with the shortest remaining CPU time is given priority. If a new process arrives with a shorter remaining time, a context switch occurs.

Using this information, we can determine the number of context switches:

1. Process 1 (arrives at time 0, requires 10 time units): No context switch
2. Process 2 (arrives at time 2, requires 20 time units): Context switch occurs at time 2
3. Process 3 (arrives at time 6, requires 30 time units): Context switch occurs at time 6

Therefore, the number of context switches in this scenario is 2 (option B).