What Is Operating System? Beginner Guide, Uses & Examples
Operating System (OS)
An operating system is an intermediary (interface) between the user of a computer and the computer hardware. The purpose of an operating system is to provide an environment in which a user can execute programs in a convenient and efficient manner. In other words it is also known as a system of software which may be viewed as an original collection of software consisting of processors for operating a computer and providing an environment for execution of program.
Function of an Operating System (OS)
It can act as an interface between the user and the hardware.
It is responsible for managing all the processes which are executed.
It is also responsible for managing the memory occupied by various processes.
It manages all the peripheral or I/O devices connected to the system.
It also manages the disc or the secondary storage device.
It helps in the proper functioning of the system and enables the user to interact effectively and provide instructions.
Goals of an Operating System (OS)
To execute the users program to make the process of solving the users program simple and easy.
To make the computer system convenient to use.
To use the computer hardware efficiently.
Types of Operating Systems
Type
Description
Examples
Batch OS
Jobs collected and processed in batches without user interaction
Early IBM systems
Time-Sharing OS
Multiple users share CPU time simultaneously
UNIX, Multics
Distributed OS
Multiple computers work together as one system
Amoeba, Plan 9
Real-Time OS (RTOS)
Processes data within strict time constraints
VxWorks, FreeRTOS
Network OS
Manages network resources and services
Windows Server, Novell NetWare
Mobile OS
Designed for mobile devices
Android, iOS
Embedded OS
Runs on embedded systems with limited resources
Embedded Linux, QNX
Key OS Components
Kernel: Core of the OS - manages CPU, memory, and device drivers.
Process Manager: Creates, schedules, and terminates processes.
Memory Manager: Allocates and deallocates memory to processes.
File System: Organizes and manages files on storage devices.
Device Drivers: Interface between OS and hardware devices.
Shell/CLI: Command-line interface for user interaction.
What OS state trace
What OS state trace
Event 1: a process requests a resource related to What
Event 2: the kernel checks permissions, availability, and current state
Event 3: the scheduler or manager decides whether to run, wait, block, or fail
Event 4: the process observes the result and continues or handles the error
What small simulation
What small simulation
Input: P1, P2, P3
Resource/state: limited
Rule: apply the What policy step by step
Output: show which process runs, waits, completes, or is denied
Always write the before-state and after-state for each step.
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Batch OS means Jobs collected and processed in batches without user interaction; a typical example is Early IBM systems.
Time-Sharing OS means Multiple users share CPU time simultaneously; a typical example is UNIX, Multics.
Distributed OS means Multiple computers work together as one system; a typical example is Amoeba, Plan 9.
Real-Time OS (RTOS) means Processes data within strict time constraints; a typical example is VxWorks, FreeRTOS.