1. What is First-Come First-Served Scheduling?

First-Come First-Served (FCFS) is a scheduling algorithm where processes are executed in the order they arrive. In FCFS scheduling, the arrival time for the next process equals the completion time of the previous process, ensuring sequential execution without preemption.

2. How Does the Calculator Work?

The calculator uses the FCFS scheduling formula:

Where:

• \( \text{Arrival Time} \) — Time when the next process arrives in the ready queue
• \( \text{Previous Completion Time} \) — Time when the previous process finishes execution

Explanation: This simple formula ensures that processes are handled in strict arrival order, making FCFS one of the simplest CPU scheduling algorithms.

3. Importance of Arrival Time Calculation

Details: Accurate arrival time calculation is crucial for process scheduling, system performance analysis, and understanding waiting times in operating systems. FCFS provides a baseline for comparing more complex scheduling algorithms.

4. Using the Calculator

Tips: Enter the previous completion time in time units. The calculator will compute the arrival time for the next process in the FCFS queue. All values must be non-negative.

5. Frequently Asked Questions (FAQ)

Q1: What are the advantages of FCFS scheduling?
A: FCFS is simple to implement, fair in process ordering, and ensures every process gets CPU time. It's easy to understand and debug.

Q2: What are the disadvantages of FCFS?
A: It can lead to convoy effect (short processes waiting behind long ones), poor response time, and inefficient CPU utilization when processes have varying burst times.

Q3: When is FCFS scheduling most appropriate?
A: FCFS works well in batch systems where jobs are similar in length, or in systems where simplicity is more important than performance optimization.

Q4: How does FCFS compare to other scheduling algorithms?
A: Unlike Round Robin or Priority Scheduling, FCFS doesn't consider process priority or time quantum, making it less responsive but more predictable.

Q5: Can FCFS cause starvation?
A: No, FCFS is non-preemptive and every process will eventually get executed, though short processes may experience long waiting times behind longer processes.