Question

Which scheduling algorithm works on the principles of time slices?

• A. FCFS
• B. Round Robin
• C. SJF
• D. Priority Scheduling

Hint:

Whenever a question mentions time slice, time quantum, or time-sharing systems, immediately think of Round Robin Scheduling. It is the scheduling algorithm most closely associated with fair CPU sharing among multiple processes.

Answer 1

The Correct Option is B

Concept: CPU scheduling is a mechanism used by the operating system to decide which process should receive CPU time whenever multiple processes are waiting for execution. Different scheduling algorithms use different criteria for selecting processes. One important concept in modern operating systems is the time slice or time quantum. A time slice is a fixed amount of CPU time allocated to a process before the CPU is reassigned to another process.

Step 1: Understanding FCFS Scheduling. FCFS stands for First-Come First-Served. Processes are executed strictly in the order in which they arrive. Once a process gets the CPU, it continues execution until completion or blocking. No time slices are used. Therefore, FCFS is incorrect.

Step 2: Understanding Round Robin Scheduling. Round Robin scheduling is specifically designed for time-sharing systems. Each process receives a fixed time quantum. After the quantum expires:
• The running process is interrupted.
• It is moved to the end of the ready queue.
• The next process receives CPU time. This cyclic allocation continues until all processes finish execution. Therefore, Round Robin directly operates on the principle of time slices.

Step 3: Understanding SJF Scheduling. Shortest Job First selects the process having the smallest CPU burst time. Its selection criterion is execution time, not time quantum. Therefore, SJF is incorrect.

Step 4: Understanding Priority Scheduling. Priority Scheduling allocates the CPU according to process priority values. The process with the highest priority executes first. Its primary criterion is priority, not time slices. Therefore, Priority Scheduling is incorrect.

Step 5: Determining the final answer. Among all the given scheduling algorithms, only Round Robin uses a fixed time quantum for process execution. Hence, the correct answer is: \[ \boxed{\text{Round Robin}} \] or \[ \boxed{(B)} \]