Operating System: Concept, Types, Functions and PYQ (Previous Year Questions)
An Operating System (OS) is system software that acts as an interface between the user and computer hardware. It manages all hardware resources such as CPU, memory, input-output devices, and storage. Without an operating system, a computer cannot function properly because there would be no coordination between software and hardware.
Common examples of operating systems include Microsoft Windows, Linux, macOS, Android and iOS.
Types of Operating System
Batch Operating System is one of the earliest types of operating systems. In this system, jobs are collected and processed in groups called batches. There is no direct interaction between the user and the system during execution. It is mainly used in large organizations for payroll systems and billing processes.
Time Sharing Operating System allows multiple users to access the computer system at the same time. The CPU time is divided among users in small time intervals. This type of system provides quick response and is commonly seen in systems like Unix.
Multiprogramming Operating System keeps several programs in memory at the same time. When one program waits for input or output, the CPU switches to another program. This increases CPU utilization and system efficiency. Modern versions of Windows 10 use multiprogramming techniques.
Multitasking Operating System allows a single user to run multiple applications simultaneously. For example, a user can listen to music, browse the internet, and type a document at the same time in systems like macOS.
Real-Time Operating System (RTOS) provides immediate response to input. It is used in critical systems such as medical equipment, air traffic control systems, and robotics. In real-time systems, delay is not acceptable because it may lead to serious consequences.
Distributed Operating System manages a group of independent computers and makes them appear as a single system to the user. It is used in large networks and research environments.
Network Operating System manages network resources and allows sharing of files, printers, and other resources over a network. An example is Windows Server.
Mobile Operating System is specially designed for smartphones and tablets. The most common mobile operating systems are Android and iOS.
Functions of Operating System
Process management is one of the most important functions of an operating system. It creates, schedules, and terminates processes. It also allocates CPU time among different programs.
Memory management controls and coordinates computer memory. It keeps track of each byte of memory and allocates space to programs when needed. It also manages virtual memory.
File system management organizes data into files and directories. It controls file access permissions and storage location.
Device management controls input and output devices such as keyboard, mouse, printer, and monitor through device drivers.
Security and protection ensure that only authorized users can access the system. It provides password protection and data encryption.
User interface allows users to interact with the system either through Command Line Interface such as MS-DOS or through Graphical User Interface such as Microsoft Windows.
Important Previous Year Questions (PYQ)
Question 1: The primary function of an operating system is
A. To compile programs
B. To manage hardware and software resources
C. To create documents
D. To edit graphics
Answer: B
Explanation: The main function of an operating system is to manage hardware and software resources.
Question 2: Which of the following is an example of a real-time operating system?
A. Windows 7
B. UNIX
C. VxWorks
D. MS Office
Answer: C
Explanation: VxWorks is a real-time operating system used in embedded systems.
Question 3: Which operating system is open source?
A. Windows
B. Linux
C. macOS
D. iOS
Answer: B
Explanation: Linux is open-source software, meaning its source code is freely available.
Question 4: The part of the operating system that interacts directly with hardware is called
A. Shell
B. Kernel
C. Compiler
D. Application
Answer: B
Explanation: Kernel is the core component of an operating system that manages hardware resources.
Question 5: Time-sharing systems are designed to
A. Execute only one job
B. Allow multiple users to share system resources
C. Increase hardware cost
D. Remove memory management
Answer: B
Explanation: Time-sharing systems divide CPU time among multiple users.
Question 6: Which of the following is not a function of an operating system?
A. Process management
B. Memory management
C. Word processing
D. File management
Answer: C
Explanation: Word processing is the function of application software, not the operating system.
Conclusion
An operating system is the backbone of a computer system. It manages hardware, controls software, provides security, and ensures smooth functioning of all processes. Understanding its types and functions is very important for competitive exams like SSC, NDA, JKSSB, Banking, and other government exams.