1. What is FCFS Scheduling?

First-Come, First-Served (FCFS) is the simplest CPU scheduling algorithm where the process that arrives first is executed first. Waiting time is calculated as the sum of previous processes' burst times.

2. How Does the Calculator Work?

The calculator uses the FCFS waiting time formula:

Where:

• \( WT \) — Waiting time for a process
• \( \sum \) — Sum of all previous processes' burst times

Explanation: The first process has 0 waiting time. Each subsequent process waits for all previous processes to complete.

3. Importance of Waiting Time Calculation

Details: Waiting time is a key metric in CPU scheduling algorithms. It helps evaluate system performance and compare different scheduling algorithms.

4. Using the Calculator

Tips: Enter burst times separated by commas (e.g., "5, 3, 8"). The calculator will compute individual waiting times, total waiting time, and average waiting time.

5. Frequently Asked Questions (FAQ)

Q1: What is the main characteristic of FCFS?
A: FCFS is non-preemptive - once a process starts, it runs to completion. It's simple but can lead to long waiting times.

Q2: What is the convoy effect in FCFS?
A: When a long process holds up shorter processes behind it, leading to increased average waiting time.

Q3: Is FCFS used in modern operating systems?
A: Rarely as the main algorithm, but elements of it are used in combination with other algorithms.

Q4: How does FCFS compare to other algorithms?
A: FCFS is simple but often results in higher average waiting times than more sophisticated algorithms like SJF or Round Robin.

Q5: Can FCFS be preemptive?
A: No, by definition FCFS is non-preemptive. The first process to arrive runs until completion.