First Come First Serve (FCFS) CPU Scheduling Algorithm - Operating Systems

Summary

This tutorial introduces the First-Come, First-Served (FCFS) CPU scheduling algorithm, detailing how it manages process execution based on arrival times. By using a numerical example with four processes (P0, P1, P2, P3), the video explains key concepts such as burst time, completion time, turnaround time, and waiting time. The instructor demonstrates how to create a Gantt chart and perform calculations to derive the total and average turnaround and waiting times. Viewers will gain a clear understanding of FCFS scheduling and its practical applications in CPU management.

Takeaways

• 😀 FCFS (First-Come, First-Served) is a non-preemptive CPU scheduling algorithm where processes are executed in the order they arrive.
• 🕒 Arrival Time is when a process enters the ready queue and is critical for determining the scheduling order.
• ⏳ Burst Time is the total time required by a process to complete its execution on the CPU.
• ✅ Completion Time is the time when a process finishes executing, calculated by adding its burst time to the previous process's completion time.
• 🔄 Turnaround Time (TAT) measures the total time from arrival to completion, providing insight into process efficiency.
• ⏰ Waiting Time (WT) is the time a process spends waiting in the queue before execution starts.
• 📊 The FCFS scheduling algorithm is simple to implement but can lead to inefficiencies such as the convoy effect, where short processes are delayed by long ones.
• 📝 Calculation of turnaround and waiting times is essential for performance analysis and can be derived from the completion times and burst times.
• 🔢 Understanding how to calculate individual parameters is crucial for solving numerical problems related to CPU scheduling.
• 📺 This tutorial emphasizes practical examples to illustrate the concepts of CPU scheduling algorithms clearly.

Q & A

What is the primary focus of the tutorial?

The tutorial focuses on CPU scheduling algorithms, specifically the First-Come, First-Served (FCFS) algorithm.

How does the FCFS algorithm determine the order of process execution?

The FCFS algorithm processes tasks in the order they arrive in the queue, meaning the first process to enter is the first to be executed.

What is the definition of 'arrival time' in the context of CPU scheduling?

Arrival time is the moment at which a process enters the queue to be processed by the CPU.

What does 'burst time' represent for a process?

Burst time is the duration required by a process to complete its execution once it starts being processed by the CPU.

What is the formula for calculating turnaround time?

The formula for calculating turnaround time is: Turnaround Time = Completion Time - Arrival Time.

How is waiting time calculated in CPU scheduling?

Waiting time is calculated using the formula: Waiting Time = Turnaround Time - Burst Time.

What is a Gantt chart, and how is it used in the tutorial?

A Gantt chart is a visual representation of the scheduling of processes over time, used in the tutorial to illustrate how each process is executed in the FCFS algorithm.

Why is it important to understand the individual parameters like completion time and turnaround time?

Understanding these parameters helps in analyzing the performance of the scheduling algorithm and its impact on process management.

What does the tutorial suggest about the complexity of the FCFS scheduling algorithm?

The tutorial suggests that the FCFS scheduling algorithm is straightforward and easy to understand, making it an excellent starting point for learning about CPU scheduling.

What action does the tutorial encourage viewers to take after watching?

The tutorial encourages viewers to practice similar problems to reinforce their understanding of CPU scheduling and to engage with the channel by liking, sharing, and subscribing.