Operating System

1. Core Functions of an OS

For the exam, you should remember these five primary responsibilities:

• Processor Management: Decides which process gets the processor when and for how much time (Scheduling).
• Memory Management: Tracks every byte of primary memory and manages the allocation/deallocation of RAM to programs.
• File Management: Organizes data into directories and folders for easy navigation and permanent storage.
• Device Management: Manages device communication via their respective drivers (e.g., printer drivers).
• Security: Prevents unauthorized access to programs and data using passwords and encryption.

2. Types of Operating Systems

• Batch OS: Similar jobs are grouped together and executed as a batch (used in older systems).
• Multitasking/Time-sharing: Allows multiple tasks to run "simultaneously" by switching the CPU between them very quickly (e.g., Windows 11).
• Real-Time OS (RTOS): Used where time requirements are very strict, such as in missile systems or air traffic control.
• Network OS: Runs on a server and provides the capability to manage data, users, and security across a network (e.g., Windows Server).
• Mobile OS: Specifically designed for handheld devices like smartphones (e.g., Android, iOS).

3. User Interface Types

The way you interact with an OS has evolved:

• CLI (Command Line Interface): The user types text-based commands (e.g., MS-DOS, Linux Terminal).
• GUI (Graphical User Interface): The user interacts using icons, menus, and pointers (e.g., Windows, macOS). This is the standard for modern IT gadgets.

4. Popular Examples (2026 Context)

• Desktop: Windows 11/12, macOS, Linux (Ubuntu/Mint).
• Mobile: Android 16, iOS 19.
• Open Source: Linux is the primary example of an open-source OS, which is a frequent MCQ topic in M1-R5.