COL331 – Operating Systems

Assignments from the Operating Systems course (COL331) at IIT Delhi, taught by Prof. S.R. Sarangi

This repository contains implementations of various operating system concepts using the xv6 teaching OS, as part of the coursework for COL331.

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📁 Assignments

Assignment 1: Shell Commands in xv6

• Implemented custom shell commands and associated system calls in xv6.
• Features:
  • history system call to display command history.
  • block and unblock system calls to control permissions for other system calls.
  • chmod system call to modify file permissions.

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Assignment 2: Signal Handling and Scheduling

• Enhanced xv6 with signal handling and a modified scheduler.
• Features:
  • Signal delivery and handling, including interrupt, background, and foreground signals.
  • Custom signal handler registration.
  • Priority boosting added to the scheduler for fairer CPU allocation.

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Assignment 3: Swap Memory Implementation in xv6

• Added swap memory support to xv6 for better memory management.
• Features:
  • Modified disk structure to accommodate swap space.
  • Implemented page swapping (in and out) between RAM and disk.
  • Adaptive page replacement policy for efficient memory usage.

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Each assignment progressively extends the functionality of the xv6 kernel, exploring real-world OS concepts such as process control, memory management, and CPU scheduling.