1. Introduction
An Operating System (OS) is a system software that manages all computer hardware and software resources, and provides common services for applications. It acts as an interface between user and hardware, enabling smooth interaction with the computer.
Without an OS, a computer cannot operate efficiently.
2. Definition of Operating System
Operating System (OS):
An operating system is a software program that manages computer hardware, provides an environment for applications to run, and ensures efficient utilization of resources.
Main Functions of OS:
- Process Management – Manages CPU processes, multitasking, and scheduling.
- Memory Management – Allocates and frees RAM as needed.
- File Management – Organizes files and directories.
- Device Management – Controls input/output devices.
- Security & Access Control – Protects data from unauthorized access.
- User Interface – Provides CLI (Command Line Interface) or GUI (Graphical User Interface).
3. Popular Operating Systems with Full Description (Versions)
3.1 Windows OS
| Name | Launch Year | Developer | Type | Features | Uses |
|---|---|---|---|---|---|
| Windows 1.0 | 1985 | Microsoft | Desktop/PC | First GUI over MS‑DOS | Early personal computers |
| Windows 3.0 | 1990 | Microsoft | Desktop/PC | Better interface and icons | PCs in colleges & offices |
| Windows 95 | 1995 | Microsoft | Desktop/PC | Start button, taskbar, better hardware support | Home and office PCs |
| Windows 98 | 1998 | Microsoft | Desktop/PC | Improved hardware support, better USB support | PCs with internet |
| Windows XP | 2001 | Microsoft | Desktop/PC | Very stable, long‑lasting | Gaming, business, education |
| Windows Vista | 2007 | Microsoft | Desktop/PC | Aero UI, security upgrades | Personal and business |
| Windows 7 | 2009 | Microsoft | Desktop/PC | User‑friendly GUI, stable | Personal computers, business, gaming |
| Windows 8 | 2012 | Microsoft | Desktop/PC | Metro interface, touch support | Tablets, PCs |
| Windows 8.1 | 2013 | Microsoft | Desktop/PC | UI improvements | Touch and PC use |
| Windows 10 | 2015 | Microsoft | Desktop/PC | Cortana, secure, continuous updates | Personal, business, gaming |
| Windows 11 | 2021 | Microsoft | Desktop/PC | Modern UI, integrated Microsoft Store | Personal computers, business |
Description:
Windows is one of the most widely used operating systems for desktops and laptops. It provides a graphical user interface (GUI) and supports a large variety of software applications and games. Over the years it evolved from simple GUIs to modern, secure, and user‑friendly environments.
3.2 Linux OS
| Name | Launch Year | Developer | Type | Features | Uses |
|---|---|---|---|---|---|
| Debian 1.1 | 1996 | Community | Server/Embedded | Stable, free | Servers, networking |
| Fedora | 2003 | Red Hat community | Desktop/Server | Cutting‑edge features | Developers, research |
| Ubuntu 4.10 | 2004 | Canonical | Desktop/Server | Open‑source, free, user‑friendly | PCs, programming |
| Ubuntu 8.04 LTS | 2008 | Canonical | Desktop/Server | Long‑term support release | Stable production use |
| Ubuntu 20.04 LTS | 2020 | Canonical | Desktop/Server | Updated software & security | Personal & servers |
| Red Hat Enterprise Linux (RHEL) | 2000 | Red Hat | Enterprise | Paid, secure for companies | Large servers, cloud |
| CentOS | 2004 | Community | Server | Free RHEL clone | Servers |
Description:
Linux is an open‑source operating system family widely used for servers, desktops, programming, and embedded systems. It is known for its security, stability, and customization. Linux distributions like Ubuntu and Fedora are used on personal computers, while RHEL and Debian are widely used in enterprise and server environments.
3.3 macOS
| Name | Launch Year | Developer | Type | Features | Uses |
|---|---|---|---|---|---|
| macOS X 10.0 | 2001 | Apple | Desktop | Unix‑based stable OS | Personal computing |
| macOS 10.4 Tiger | 2005 | Apple | Desktop | Spotlight search | Multimedia, education |
| macOS 10.8 Mountain Lion | 2012 | Apple | Desktop | Enhanced notifications | Productivity |
| macOS 10.12 Sierra | 2016 | Apple | Desktop | Siri integration | Creative work |
| macOS 10.15 Catalina | 2019 | Apple | Desktop | Dropped 32‑bit support | Multimedia creation |
| macOS 11 Big Sur | 2020 | Apple | Desktop | Redesigned UI, Apple Silicon support | Design, development |
| macOS 12 Monterey | 2021 | Apple | Desktop | Focus modes, FaceTime updates | Productivity |
| macOS 13 Ventura | 2022 | Apple | Desktop | Continuity features | Creative & business |
| macOS 14 Sonoma | 2023 | Apple | Desktop | Performance & widgets | Personal & professional |
Description:
macOS is an operating system developed by Apple exclusively for Apple computers like iMac and MacBook. It is known for its sleek design, stability, and excellent support for creative tasks, such as video editing, graphic design, and software development.
3.4 Android OS
| Name | Launch Year | Developer | Type | Features | Uses |
|---|---|---|---|---|---|
| Android 1.0 | 2008 | Mobile OS | Basic smartphone functions | Early Android phones | |
| Android 2.3 Gingerbread | 2010 | Mobile OS | UI improvements | Smartphones | |
| Android 4.0 Ice Cream Sandwich | 2011 | Mobile OS | Unified phone & tablet | Mobile & tablets | |
| Android 4.4 KitKat | 2013 | Mobile OS | Optimized for low devices | Budget phones | |
| Android 5 Lollipop | 2014 | Mobile OS | Material Design | Apps & media | |
| Android 6 Marshmallow | 2015 | Mobile OS | App permissions | Secure apps | |
| Android 8 Oreo | 2017 | Mobile OS | Picture‑in‑picture | Multi‑tasking | |
| Android 9 Pie | 2018 | Mobile OS | AI features | Smart phones | |
| Android 10 | 2019 | Mobile OS | System‑wide dark mode | Broad use | |
| Android 12 | 2021 | Mobile OS | Improved UI & privacy | All Android devices | |
| Android 13 | 2022 | Mobile OS | Security dashboard | Phones & tablets | |
| Android 14 | 2023 | Mobile OS | App predictive back gestures | Phones | |
| Android 15 | 2024 | Mobile OS | Performance & privacy | Latest Android | |
| Android 16 | 2025* | Mobile OS | AI features (expected) | Future smartphones |
Description:
Android is the most widely used mobile operating system in the world. Developed by Google, it is flexible, supports millions of apps, and is used on billions of smartphones, tablets, and smart devices.
3.5 iOS
| Name | Launch Year | Developer | Type | Features | Uses |
|---|---|---|---|---|---|
| iPhone OS 1 | 2007 | Apple | Mobile OS | Basic touch interface | Early iPhones |
| iOS 4 | 2010 | Apple | Mobile OS | Multitasking | Phones & iPads |
| iOS 7 | 2013 | Apple | Mobile OS | Flat UI design | Modern interface |
| iOS 10 | 2016 | Apple | Mobile OS | Improved notifications | iPhones, iPads |
| iOS 12 | 2018 | Apple | Mobile OS | Performance focus | Phones & tablets |
| iOS 14 | 2020 | Apple | Mobile OS | Widgets | Customization |
| iOS 15 | 2021 | Apple | Mobile OS | Focus modes | Communication |
| iOS 16 | 2022 | Apple | Mobile OS | Lock screen updates | Personal |
| iOS 17 | 2023 | Apple | Mobile OS | Contact poster | Messaging |
| iOS 18 | 2024 | Apple | Mobile OS | Advanced personalization | Latest Apple |
| iOS 19 | 2025* | Apple | Mobile OS | AI features (speculated) | Next generation |
Description:
iOS is Apple’s mobile operating system used on iPhones and iPads. It is known for its smooth performance, strong security, and rich app ecosystem from the Apple App Store.
4. Operating System Types (Brief)
(Ye pehle waale jaisa hi table aur definitions — Batch OS, Time‑Sharing OS, Real‑Time OS, Network OS, Distributed OS, Mobile OS, Embedded OS)
5. System Configuration & Specifications
| Component | Recommended |
|---|---|
| CPU | 1 GHz+ (32/64 bit) |
| RAM | 4 GB+ |
| Storage | 40 GB+ |
| Display | 1024×768+ |
6. 32‑bit vs 64‑bit OS
| Feature | 32‑bit | 64‑bit |
|---|---|---|
| Max RAM | ~4 GB | >4 GB |
| Performance | Lower | Higher |
| Software | 32‑bit only | 32/64‑bit |
