UNIVERSITY OF WEST ATTICA
SCHOOL OF ENGINEERING
DEPARTMENT OF COMPUTER ENGINEERING AND INFORMATICS

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Operating Systems II

Process Management with Fork and Wait in C

Vasileios Evangelos Athanasiou
Student ID: 19390005

GitHub · LinkedIn

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Supervision

Supervisor: Vasileios Mamalis, Professor

UNIWA Profile

Co-supervisor: Nikolaos Psarras, Applications Lecturer

UNIWA Profile · LinkedIn

Athens, April 2022

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Process Management with Fork and Wait in C

This repository contains an assignment for Operating Systems II, focusing on process creation, management, and synchronization in C using fork() and wait() system calls.

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Table of Contents

Section	Folder/File	Description
1	assign/	Assignment material for the Fork processes workshop
1.1	assign/ASK-1-OS-II-LAB-2021-22.pdf	Assignment description in English
1.2	assign/ΕΡΓ-1-ΛΣ-ΙΙ-ΕΡΓ-2021-22.pdf	Assignment description in Greek
2	docs/	Documentation covering process creation using fork
2.1	docs/Fork-Processes.txt	English documentation for fork processes
2.2	docs/Fork-Διεργασίες.txt	Greek documentation for fork processes
3	src/	Source code demonstrating fork usage
3.1	src/exer1a.c	Exercise source code using fork
3.2	src/fork.c	Basic fork process example
4	README.md	Repository overview and usage instructions

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Project Overview

The assignment involves developing a C program that:

• Creates a total of seven processes following a specific hierarchy.
• Implements process synchronization to avoid zombie processes.
• Demonstrates inter-process communication.
• Explores scenarios with orphan and zombie processes.
• Allows process P2 to spawn N child processes dynamically based on user input.

Key Learning Outcomes

• Understand and apply fork() and wait() system calls.
• Create and manage process hierarchies.
• Synchronize parent and child processes effectively.
• Handle inter-process communication and message passing.
• Investigate orphan and zombie processes and prevention techniques.

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Process Tree Structure

The program creates processes with the following hierarchy:

			  (P0)
			  /|\
			 / | \
            /  |  \
	       /   |   \ 
          /    |    \
        (P1)  (P3) (P4)
        /      |
       /       |
      /        | 
     /         |
   (P2)       (P5)

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Requirements

• Operating System: Linux or Unix-like environment
• Compiler: GCC (GNU Compiler Collection)
• System Calls: fork(), wait(), execv(), and others as needed

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Installation & Usage

1. Clone the Repository

git clone https://github.com/Operating-Systems-2-aka-Uniwa/Fork.git
cd Fork

2. Compile Source Code

gcc -o exer1a exer1a.c
gcc -o fork fork.c

3. Run Executables

./exer1a
./fork