1. What is SJF Scheduling?

Shortest Job First (SJF) is a scheduling algorithm where the process with the smallest burst time is executed first. It minimizes average waiting time among all scheduling algorithms but requires knowledge of burst times in advance.

2. How Does the Calculator Work?

The calculator uses the SJF algorithm formula:

Where:

• \( WT \) — Waiting time for each process
• \( n \) — Number of processes
• \( \sum WT \) — Sum of all waiting times

Explanation: The calculator first sorts processes by burst time, then calculates waiting time for each process (time it waits before execution starts), and finally computes the average.

3. Importance of Waiting Time Calculation

Details: Average waiting time is a key metric in CPU scheduling that measures how long processes wait in the ready queue. Minimizing it improves system performance and user experience.

4. Using the Calculator

Tips: Enter burst times (execution durations) separated by commas. The calculator will sort them, compute individual waiting times, and calculate the average.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between SJF and SRTF?
A: SJF is non-preemptive while Shortest Remaining Time First (SRTF) is preemptive. SRTF can preempt a running process if a shorter one arrives.

Q2: Is SJF practical in real systems?
A: Pure SJF is rarely used because burst times aren't known in advance, but approximations exist (e.g., using predicted burst times).

Q3: What's the main advantage of SJF?
A: It provides the minimum average waiting time for given set of processes compared to other scheduling algorithms.

Q4: What's the main disadvantage of SJF?
A: It can lead to starvation of longer processes if many short processes keep arriving.

Q5: How does SJF compare to Round Robin?
A: SJF typically has better average waiting time but worse response time variance, while Round Robin provides fairer CPU allocation.