An Operating System (OS) is system software that manages hardware and software resources on a computer or device. It provides a user interface, manages files and directories, and controls peripheral devices. The OS handles multitasking, allowing multiple applications to run simultaneously, and ensures system stability and security. It allocates resources like CPU time and memory, manages system processes, and provides essential services for application programs. Common examples include Windows, macOS, Linux, and Android. By acting as an intermediary between users and hardware, the OS enables efficient and organized operation of computer systems.
Functions to Operating System:
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Process Management:
OS handles the creation, scheduling, and termination of processes. It ensures that multiple processes can run simultaneously by managing CPU time through process scheduling. It allocates resources to processes, manages process states (running, waiting, etc.), and handles process synchronization and inter-process communication.
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Memory Management:
OS manages system memory by allocating and deallocating memory space as needed. It tracks memory usage, handles virtual memory (paging and swapping), and ensures that each process has sufficient memory without interfering with others. This function optimizes the use of RAM and provides mechanisms to manage memory leaks and fragmentation.
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File System Management:
OS manages files and directories on storage devices. It provides a hierarchical file system structure, handles file operations like creation, deletion, and modification, and ensures file access control. It manages file permissions, organization, and storage allocation to efficiently use disk space.
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Device Management:
OS controls hardware devices such as printers, disk drives, and network interfaces. It uses device drivers to communicate with hardware, providing an abstraction layer that allows applications to interact with devices without needing to know the specifics of the hardware. It handles device scheduling, input/output operations, and error management.
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User Interface:
OS provides a user interface (UI) that can be command-line or graphical. The UI enables users to interact with the computer system, execute commands, run applications, and manage files. It offers tools for user input, system feedback, and interaction, enhancing usability and accessibility.
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Security and Access Control:
OS ensures system security by managing user authentication and access control. It provides mechanisms for user login, password management, and permissions. It protects system resources from unauthorized access and implements security policies to safeguard against threats and vulnerabilities.
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Network Management:
OS manages network connections and communications. It handles network protocols, data transmission, and network device configuration. It facilitates internet and intranet access, supports network services, and provides tools for managing network traffic and connectivity.
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System Performance Monitoring:
OS monitors and manages system performance by tracking resource usage, system health, and application performance. It provides tools for performance analysis, diagnostics, and optimization, helping to ensure efficient operation and responsiveness of the system.
Types to Operating System:
1. Batch Operating System
A batch operating system groups similar jobs together and executes them one after another without user interaction, using punched cards or magnetic tape in early systems. It improves CPU utilisation but causes long waiting times, and debugging is difficult because the user cannot interact with the job while it runs. Examples include IBM’s IBSYS and early mainframe systems. Batch processing is still used today for payroll, bank statements and billing in banks, railways and large organisations in India and worldwide.
2. Multiprogramming Operating System
A multiprogramming operating system keeps several programs in main memory at the same time. When one program waits for input or output, the CPU switches to another, so it is rarely idle. This increases CPU utilisation and throughput, though it needs careful memory management and job scheduling. Early mainframe systems such as IBM OS/360 introduced the concept, and it forms the foundation of all modern operating systems used on servers, desktops and smartphones.
3. Time-Sharing (Multitasking) Operating System
A time-sharing operating system gives each user or program a small slice of CPU time, called a time quantum, switching so quickly that many users can work interactively. It provides fast response times and reduces idle time. UNIX, Linux, Windows and macOS are common examples, and multitasking is used daily on Indian laptops and smartphones. Challenges include security, data protection and the overhead of frequent switching, so access controls and user authentication are essential.
4. Multiprocessing Operating System
A multiprocessing operating system controls computers with two or more processors or cores that work together to execute tasks simultaneously. It offers higher speed, better throughput and greater reliability, since another processor can continue if one fails. Types include symmetric multiprocessing (SMP) and asymmetric multiprocessing (AMP). Windows Server, Linux and Unix variants support it, and it is used in servers, data centres, supercomputers such as India’s PARAM series, and modern multi-core smartphones.
5. Distributed Operating System
A distributed operating system manages a group of independent computers connected by a network and makes them appear to users as a single system. Resources, processing load and data are shared across machines, improving speed, scalability and fault tolerance. Examples include Amazon’s cloud infrastructure, Google’s server clusters and Amoeba. It is used in banking networks, cloud services and large e-commerce platforms. Because data moves across networks, security duties under the IT Act, 2000 (Section 43A) and the DPDP Act, 2023 apply.
6. Network Operating System (NOS)
A network operating system runs on a server and lets multiple computers share files, printers, applications and user accounts over a network, with centralised administration and security. Examples include Windows Server, Linux server editions, Novell NetWare and UNIX. It is used in offices, universities and government departments in India and globally. It supports user authentication and access control, helping meet “reasonable security practices” under Section 43A of the IT Act, 2000, while unauthorised access is punishable under Section 43 and Section 66.
7. Real-Time Operating System (RTOS)
A real-time operating system processes data and responds within a strict, guaranteed time limit. Hard real-time systems cannot tolerate delay, as in airbags, pacemakers, missile control and air traffic control, while soft real-time systems tolerate small delays, as in video streaming and online gaming. Examples include VxWorks, FreeRTOS and QNX. India’s ISRO uses real-time systems in satellite and launch vehicle operations. RTOS is valued for reliability and predictability, though it is costly to design and has limited multitasking features.
8. Mobile Operating System
A mobile operating system is designed for smartphones, tablets and wearables, with touch interfaces, battery management, wireless connectivity, sensors and app stores. Major examples are Android (Google, open-source base) and iOS (Apple), and Android holds the largest share of the Indian market. Mobile systems run UPI apps, DigiLocker and WhatsApp. Since they collect location, contacts and biometric data, developers and providers must follow consent and security rules under the DPDP Act, 2023, and app-based fraud is punishable under Section 66D of the IT Act, 2000.
9. Embedded Operating System
An embedded operating system is a compact system built into a specific device to perform dedicated functions with limited memory and power. It is found in washing machines, smart TVs, ATMs, routers, cars, medical devices and IoT sensors. Examples include Embedded Linux, FreeRTOS and Android Things. These systems are reliable and efficient but offer little flexibility for users to change functions. Because connected devices collect personal data, security and consent obligations under the DPDP Act, 2023 and Section 43 of the IT Act, 2000 apply.
Example to Operating System:
1. Microsoft Windows
Microsoft Windows is the world’s most widely used desktop operating system, offering a graphical interface, multitasking, plug-and-play device support and a vast library of applications. Versions include Windows 10 and Windows 11, along with Windows Server for networks. It is used in homes, offices, schools and government departments across India and globally. Windows is proprietary software, so a valid licence is needed, and pirated copies violate the Copyright Act, 1957 (Section 63). Unauthorised access to Windows systems is punishable under Section 43 and Section 66 of the IT Act, 2000.
2. Linux
Linux is an open-source, multiuser and multitasking operating system kernel, distributed as Ubuntu, Red Hat, Fedora and Debian. It powers most web servers, cloud platforms, supercomputers and Android devices worldwide. India’s BOSS Linux, developed by C-DAC, is used in government offices under the National Policy on Open Source Software (2015). Linux is released under the GNU General Public Licence (GPL), which lets users study, modify and redistribute the code. It is valued for stability, security and low cost in education and enterprise use.
3. macOS
macOS is Apple’s proprietary desktop operating system for MacBook, iMac and Mac Mini computers. It is based on a UNIX foundation and is known for its polished graphical interface, strong security, and smooth integration with iPhone, iPad and iCloud. It is popular among designers, video editors, developers and creative professionals globally, including in India’s media and IT industries. Features include Spotlight search, Time Machine backup and Gatekeeper protection. Licence terms are enforceable under the Indian Contract Act, 1872, and unlicensed copying violates the Copyright Act, 1957.
4. UNIX
UNIX is a powerful, portable, multiuser and multitasking operating system developed at Bell Labs in 1969-70 by Ken Thompson and Dennis Ritchie. It introduced ideas such as hierarchical file systems, pipes and a command-line shell, and it influenced Linux, macOS and Android. Variants include Solaris, AIX and HP-UX, used in banking, telecom and enterprise servers. It is known for stability, security and efficient handling of many users. Access controls in UNIX help organisations meet “reasonable security practices” under Section 43A of the IT Act, 2000.
5. Android
Android, developed by Google on a modified Linux kernel, is the most widely used mobile operating system in the world and holds the largest share of the Indian smartphone market. It runs on devices from Samsung, Xiaomi, Realme and many others, and supports apps through the Google Play Store. Popular apps include UPI apps, DigiLocker and WhatsApp. Since apps collect location, contacts and biometric data, developers must follow consent and security duties under the DPDP Act, 2023, while app-based fraud is punishable under Section 66D of the IT Act, 2000.
6. iOS
iOS is Apple’s proprietary mobile operating system for iPhone, with iPadOS for tablets. It is known for smooth performance, regular updates, strong privacy controls, and features such as Face ID and Touch ID. Apps are distributed through the Apple App Store after review. iOS is popular among premium smartphone users in India and worldwide, and runs UPI apps and banking apps securely. Because it handles biometric and personal data, providers and app developers must comply with the DPDP Act, 2023, and identity theft is punishable under Section 66C of the IT Act, 2000.
7. MS-DOS
MS-DOS (Microsoft Disk Operating System) was an early single-user, single-tasking operating system with a command-line interface, widely used on IBM PCs in the 1980s and early 1990s. Users typed commands such as DIR, COPY and FORMAT to manage files. It had no graphical interface, and Windows originally ran on top of it. MS-DOS is a classic example of an early personal computer operating system and helps students understand how modern systems evolved. Its limitations led to the development of graphical and multitasking systems like Windows.
8. VxWorks and FreeRTOS (Real-Time Operating Systems)
VxWorks and FreeRTOS are real-time operating systems that respond within strict time limits. VxWorks is used in aircraft, Mars rovers, medical devices and defence systems, while FreeRTOS is an open-source system common in IoT devices, sensors and microcontrollers. India’s ISRO uses real-time systems in satellite and launch vehicle operations. They are valued for reliability and predictability, though they offer limited multitasking and user features. Connected devices using them must meet security and consent duties under the DPDP Act, 2023 and Section 43 of the IT Act, 2000.
