Introduction

An operating system (OS) is software that acts as an interface between computer hardware and software applications. It manages the computer’s hardware and resources, providing a foundation upon which applications can run.

The operating system performs a variety of essential tasks such as managing system resources such as memory and processing power, providing security features, managing input/output operations, and providing a user interface. It also provides a platform for software applications to run, allowing them to interact with the hardware and other system resources through various abstractions that the operating system provides.

The fundamental services of an operating system include:

  1. Process management: An operating system manages processes, which are programs or applications running on the computer. It allocates system resources such as memory and CPU time to each process, and ensures that processes run smoothly and without interference.

  2. Memory management: An operating system manages memory by allocating memory to processes and controlling access to memory by different applications. It also handles memory swapping and virtual memory management.

  3. Device management: An operating system manages input and output devices such as keyboards, mice, printers, and displays. It provides drivers for hardware devices and handles data transfer between the devices and the computer.

  4. File system management: An operating system manages files and directories on storage devices such as hard drives and flash drives. It provides mechanisms for creating, accessing, and organizing files, and ensures that data is stored and retrieved reliably.

  5. Security: An operating system provides security features to protect the computer from unauthorized access and ensure data privacy. It includes features such as user authentication, access controls, encryption, and firewalls.

  6. Networking: An operating system provides networking features to enable communication between computers and other devices on a network. It includes network protocols, device drivers, and other features needed for communication.

  7. User interface: An operating system provides a user interface for users to interact with the computer. This includes graphical user interfaces (GUIs), command-line interfaces (CLIs), and other types of interfaces that allow users to interact with the system.

In this course, we will study the Unix family of operating systems, which comprise the vast majority of operating systems in use today. You are likely already familiar with several of them, such as MacOS, Android, and Linux-based OS. The only notable extant competitor to this family of operating systems is Microsoft Windows. There are certainly also innumerable historic, niche, and experimental operating systems, which may differ in significant ways. Despite this, due to its dominance and far-reaching influence, our study of Unix as a model will provide a comprehensive, foundational understanding of the principles and ideas that underlie all of these different systems.