Introduction to Operating Systems

Study Notes

Introduction to Operating Systems

Operating systems (OS) are system software that manage computer hardware and software resources.
They act as intermediaries between applications and hardware.
Fundamental functions include process management, memory management, file system management, input/output management, and security.
Examples include Windows, macOS, Linux, and Android.

Process Management

Involves creating, scheduling, and managing process execution.
A process is a running program instance.
Scheduling algorithms dictate execution order (e.g., FCFS, SJF, Priority).
Process synchronization manages concurrent access to shared resources.
Deadlock avoidance prevents processes from being permanently blocked.

Memory Management

Allocates and deallocates memory to processes.
Virtual memory lets processes access more memory than physically available.
Techniques include paging (fixed-size blocks) and segmentation (variable-size blocks).

File System Management

Organizes and manages files and directories on storage devices.
Manages file creation, deletion, reading, writing, and other operations.
Different file systems have varying structures (e.g., FAT32, NTFS, ext4).
Features include file permissions, quotas, and directory management.

Input/Output (I/O) Management

Handles communication between the computer and external devices.
Drivers translate OS requests to device-specific commands.
Common devices include printers, keyboards, mice, and hard drives.
Buffers improve efficiency by temporarily storing data.

Security

Implements security measures against unauthorized access.
Access control mechanisms restrict resource access.
Authentication verifies user identities (e.g., passwords, biometrics).
Enforces security policies and provides data encryption.

Types of Operating Systems

Batch systems execute processes in batches sequentially.
Real-time operating systems (RTOS) meet strict deadlines.
Time-sharing systems allow concurrent user access to shared resources.
Distributed systems manage resources across multiple interconnected computers.
Mobile operating systems are designed for mobile devices (e.g., phones, tablets).
Embedded operating systems are optimized for specific embedded systems and limited resources.

Kernel

The core of the operating system.
Directly interacts with hardware, providing services to applications.
Manages processes, memory, and I/O devices.
Different kernels have varying architectures and capabilities.

Shell

A user interface for interacting with the operating system.
Interprets and executes commands.
Examples include Bash (Linux), Zsh (Linux, macOS), and CMD (Windows).

System Calls

The interface between application software and the operating system.
Allow applications to request kernel services.
Essential for processes to access hardware and resources.

Description

This quiz covers the fundamentals of operating systems, including their key functions and management tasks. It delves into process management, scheduling algorithms, and the overall role of an OS as an intermediary between hardware and applications. Test your knowledge on various OS examples and critical management strategies.