SJF (Shortest Job First) in Operating Systems - Mini Project: Build & Apply

Understanding SJF (Shortest Job First) Scheduling

📖 Scenario: You are learning how operating systems decide which task to run next. One common method is called Shortest Job First (SJF), where the system picks the task that needs the least time to finish.Imagine you have several tasks waiting, each with a different time needed to complete. Your goal is to organize these tasks so the shortest ones run first.

🎯 Goal: Build a simple list of tasks with their durations, then sort them using the SJF method to see which task runs first.

📋 What You'll Learn

Create a list of tasks with their exact names and durations

Add a variable to hold the number of tasks

Sort the tasks by their duration using SJF logic

Display the sorted list of tasks in order of execution

💡 Why This Matters

🌍 Real World

Operating systems use SJF scheduling to improve efficiency by running shorter tasks first, reducing waiting time for many tasks.

💼 Career

Understanding SJF helps in roles like system administration, software development, and performance optimization where task scheduling matters.

1

Create the list of tasks

Create a list called tasks with these exact tuples: ("Task1", 6), ("Task2", 2), ("Task3", 8), ("Task4", 3) where each tuple has the task name and its duration.

Operating Systems

# Create the list of tasks with their durations
# Your code here

Need a hint?

Use a list of tuples. Each tuple has a string and a number.

2

Add a variable for the number of tasks

Create a variable called num_tasks and set it to the length of the tasks list.

Operating Systems

tasks = [("Task1", 6), ("Task2", 2), ("Task3", 8), ("Task4", 3)]
# Create num_tasks as the count of tasks
# Your code here

Need a hint?

Use the len() function to count items in the list.

3

Sort tasks by duration using SJF logic

Sort the tasks list by the second item in each tuple (the duration) using the sort() method with a key argument.

Operating Systems

tasks = [("Task1", 6), ("Task2", 2), ("Task3", 8), ("Task4", 3)]
num_tasks = len(tasks)
# Sort tasks by duration (second item in tuple)
# Your code here

Need a hint?

Use tasks.sort(key=lambda task: task[1]) to sort by duration.

4

Display the sorted tasks in order

Create a list called execution_order that contains only the task names from the sorted tasks list using a list comprehension.

Operating Systems

tasks = [("Task1", 6), ("Task2", 2), ("Task3", 8), ("Task4", 3)]
num_tasks = len(tasks)
tasks.sort(key=lambda task: task[1])
# Create execution_order list with task names only
# Your code here

Need a hint?

Use a list comprehension to get the first item of each tuple.