Operating Systems Functions Overview

An operating system (OS) is software that manages computer hardware and software resources.
Provides common services for computer programs.

Process Management
- Handles processes in execution.
- Supports multitasking and process scheduling.
Memory Management
- Allocates and deallocates memory space as needed.
- Manages memory hierarchies (RAM, cache).
File System Management
- Manages data storage in files and directories.
- Provides access control, organization, and storage retrieval.
Device Management
- Manages device communication via drivers and interfaces.
- Handles input/output operations for hardware devices.
User Interface
- Provides user interaction via Command Line Interface (CLI) or Graphical User Interface (GUI).
Security and Access Control
- Protects data and resources from unauthorized access.
- Implements user authentication and permissions.

Batch Operating Systems
- Processes jobs in batches without interaction.
Time-Sharing Operating Systems
- Allows multiple users to access the system simultaneously.
Distributed Operating Systems
- Manages a group of distinct computers and makes them appear as a single coherent system.
Embedded Operating Systems
- Designed for specialized devices, often with limited resources (e.g., IoT devices).
Real-Time Operating Systems
- Requires timely processing and responses; used in critical systems (e.g., automotive, medical).

Kernel: Core component that manages system resources.
User Mode and Kernel Mode: Two modes in which processes can operate, protecting system integrity.
System Calls: Interfaces for programs to interact with the OS.

An operating system (OS) acts as a software intermediary between computer hardware and the software applications running on it.
It provides a standardized interface for programs to interact with the hardware, simplifying software development and execution.

Process Management: Controls the execution of programs, managing resources like CPU time and memory. Enables multitasking, allowing multiple programs to run concurrently.
Memory Management: Organizes and allocates memory to programs, optimizing utilization and preventing conflicts. Manages the various levels of memory (RAM, cache) for efficient data access.
File System Management: Organizes data into files and directories, storing and retrieving information. Provides security features like access control, protecting data from unauthorized use.
Device Management: Communicates with hardware devices through drivers, allowing programs to interact with peripherals.
User Interface: Provides a way for users to interact with the operating system, either through a graphical user interface (GUI) or a text-based command-line interface (CLI).
Security and Access Control: Protects the system and data from unauthorized access. It involves user authentication, permission management, and security policies.

Batch Operating Systems: Process tasks in batches without user intervention.
Time-Sharing Operating Systems: Allow multiple users to access the system simultaneously, with each user having a slice of CPU time.
Distributed Operating Systems: Manage multiple independent computers and present them as a single, unified system.
Embedded Operating Systems: Designed for specialized devices with limited resources, often used in Internet of Things (IoT) devices or appliances.
Real-Time Operating Systems (RTOS): Prioritize timely completion of tasks, often used in systems where immediate response is critical, such as medical devices or automotive systems.

Kernel: The core component of an OS, responsible for managing system resources.
User Mode and Kernel Mode: Two modes in which processes can operate. User mode restricts program access to prevent system disruption, while kernel mode allows access to all resources.
System Calls: Instructions used by programs to request specific services from the operating system.

Throughput: Measures the number of processes completed within a specific timeframe. Represents how efficiently the system handles workload.
Latency: Indicates the time taken for the system to respond to a user request. Represents the time taken for a task to execute.
Resource Utilization: Measures how effectively system resources are utilized, indicating efficiency. A high utilization level suggests optimal resource usage.

Increased focus on security and privacy: Modern OS development places emphasis on secure and private user experiences.
Lightweight and container-based operating systems: Systems like Docker offer lightweight and isolated environments for running applications, improving resource efficiency and portability.
Virtualization and cloud computing integration: Modern OS often integrate with virtualization technologies and cloud platforms for improved scalability and resource sharing.