What is an operating system?

An operating system is a special type of computer program that manages all other programs on a computing device, such as a desktop or laptop computer, a smartphone, a tablet, or a game console.

Main Roles of an Operating System

The operating system (OS) is essential for making the computer work properly. It manages hardware and software, and allows users to interact with the system. Below are its main functions:

• Resource Management
  • Manages hardware resources: CPU, RAM, disk, input/output devices.
  • Allocates resources to programs and users efficiently.

• File System Management
  • Organizes and manages files and directories.
  • Controls access to stored data (read, write, delete, modify).
  • Ensures data is stored and retrieved correctly.

• Memory Management
  • Keeps track of memory usage (what is being used and by whom).
  • Allocates memory to programs and frees it when no longer needed.
  • Prevents memory conflicts between programs.

• Process Management
  • Controls running programs (called processes).
  • Handles multitasking and scheduling.
  • Manages process creation, execution, and termination.

• Device Management
  • Manages communication with hardware devices.
  • Uses drivers to translate OS commands into hardware actions.
  • Controls input/output operations.

• User Interface (UI)
  • Provides a way for users to interact with the computer.
  • Types of UI:
    • Graphical User Interface (GUI) — e.g., Windows, macOS
    • Command-Line Interface (CLI) — e.g., Linux terminal

• Security and Access Control
  • Protects the system from unauthorized access.
  • Manages user accounts and permissions.
  • Ensures data privacy and system integrity.

• Networking
  • Allows communication with other computers and devices.
  • Manages network connections and data transfer.
  • Supports internet protocols (TCP/IP, HTTP, FTP, etc.).

• System Monitoring and Performance
  • Tracks system activity and performance.
  • Provides tools to monitor CPU, memory, and storage usage.
  • Helps troubleshoot issues (e.g., Task Manager in Windows).

Operating system allows the user and software to interact with the hardware

The operating system allows the user and software to interact with the hardware. It translates high-level commands (like opening a file or playing a video) into low-level instructions that the hardware can understand.

Low-Level Instructions and Programming Languages

A low-level instruction is a very basic command that a computer's CPU (central processing unit) can understand and execute directly. Low-level languages are closer to machine code and faster for the computer to execute.

Machine code is the binary language (0s and 1s) that the CPU understands directly.

1. Software programs (like Word, Chrome, etc.) are written in high-level languages

   → e.g., C++, JavaScript, Python...

2. These programs are compiled or interpreted

   → The code is gradually transformed into instructions the processor can understand.

3. The operating system (like Windows) acts as a translator

   → It manages memory, files, hardware, etc., using low-level instructions.

4. In the end, the processor executes machine code (made of 0s and 1s)

   → This code corresponds to instructions similar to those written in Assembly.

High-Level in python
Add two numbers

a = 2 + 3

Low-Level Language in Assembly

MOV AX, 2ADD AX, 3

This instruction is then translated into machine code:

10111000 00000001

What are the different types and providers of operating systems?

• Desktop operating systems (e.g., Windows, macOS, Linux)

• Mobile operating systems (e.g., Android, iOS)

• Server operating systems (e.g., Windows Server, Ubuntu Server, Red Hat Enterprise Linux)

• Embedded operating systems (e.g., RTOS, Android Things)

Exercise

What is the version of your Operating system ?

How do you update your operating system ?