CSE331 Operating Systems Design

Overview

This repository contains solutions and documentation for assignments and term projects of the CSE331 Operating Systems Design course at Yeditepe University, Fall 2024. Below is a summary of the tasks for each assignment and project phase.

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Assignments

Assignment 1: UNIX Processes and POSIX Threads

Objective:

Explore and compare three programming paradigms: multi-process, multithreaded (with and without mutual exclusion), and single-process programming, by performing operations on a long array.

Tasks:

1. Multi-Process Program: Parent process creates child processes, each incrementing elements in its designated subarray. Parent collects results and calculates execution time.
2. Multi-Threaded Program with Mutual Exclusion: Threads increment elements in their assigned subarrays with synchronization using mutual exclusion mechanisms.
3. Multi-Threaded Program without Mutual Exclusion: Threads increment subarray elements without synchronization.
4. Single-Process Program: A single process updates the entire array.

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Assignment 2: POSIX Semaphores and Shared Semaphores

Objective:

Compare multi-process programs with shared semaphores and multi-threaded programs using POSIX semaphores for unsharp filtering of images.

Tasks:

1. Multi-Process Program with Shared Semaphores:
   • Perform Laplacian filtering followed by matrix subtraction.
   • Use POSIX semaphores to synchronize operations between child processes.
2. Multi-Threaded Program with POSIX Semaphores:
   • Similar functionality as the multi-process program, but implemented using threads and POSIX semaphores.

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Term Project

Phase 1: System Calls

Objective:

Implement a new system call in Linux that provides information about the current process.

Tasks:

1. Add a system call, getProcInfoF24, to return details such as PID, parent PID, user ID, and a calculated value.
2. Write a user-space program to test the system call and demonstrate functionality for valid and invalid inputs.

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Phase 2: Fair-Share Scheduler

Objective:

Modify the Linux scheduler to implement fair-share scheduling and compare its performance with the default scheduler.

Tasks:

1. Implement a New Scheduling Policy: Modify kernel/sched.c to allocate CPU resources fairly among users.
2. Enable/Disable Custom Scheduler: Add a system call to toggle the custom scheduler.
3. Develop Performance Instrumentation: Collect detailed performance metrics for both schedulers and analyze results.

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Prepared for: CSE331 Operating Systems Design, Yeditepe University, Fall 2024.
Phase 1, Assigment 1, Assigment 2 Prepared by: Ulaş Can Demirbağ
Phase 2 Prepared by: Ulaş Can Demirbağ, Mevlüt Akif Şahin, Emirhan Tala