Thu 28 March 2024
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Operating System

An operating system is a set of programs that manages all computer components and operations. A computer can do nothing without an operating system. The operating system must be installed on every computer. Users interact with the computer through the operating system.

When the computer is turned on, the operating system runs and checks that all parts of the computer are functioning properly. The operating system manages all operations on the computer after loading.

The operating system is a set of programs that ads as an interface between a user of a computer and computer hardware. Some popular operating systems are DOS, Windows, UNIX, 05/2, Linux, etc.

 

Multi-user, Multiprocessing, Multitasking, Multithreading & Time Sharing OS

A multi-user operating system allows multiple users to use the same computer at the same time. Some examples of multi-user operating systems are Linux, UNIX, and Windows 2000.

An operating system that supports two or more processors that running programs at the same time is called a multiprocessor operating system. Some examples of multiprocessing Operating Systems are Linux, UNIX, and Windows 2000.

An operating system that can execute more than one program at the same time is called a multitasking operating system. Some examples of multitasking Operating Systems are UNIX and Windows 2000.

An operating system then allows different parts of a program to run concurrently is called multithreading operating system. Some examples of multithreading operating systems are Linux, UNIX, and Windows 2000.

A Time-sharing system allows many users to share the computer simultaneously. It is used when several users are linked through communication networks to a single computer. The computer first works on one user‘s task for a fraction of time and then goes to the next user's task. The computer operates very quickly and can distribute time to various tasks. The computer rapidly switches back and forth among different tasks.

 

Functions of Operating System

The operating system performs the following functions:

1. Booting

Booting is a process of starting the computer. The operating system starts the computer to work. It checks the computer and makes it ready to work. There are two types of booking:

  1. Cold Boot: When the computer is turned on after it has been powered off completely, it is called cold boot.
  2. Warm Boot: When the computer is restarted, it is called warm boot.

When the booking process takes place, the kernel and important instructions of the operating system are copied from hard disk to main memory (RAM). The kernel is the most important pan of the operating system that manages memory and devices, maintains computer clock, starts applications, and assigns computer resources like devices, programs, data, and information, etc. Kernel remains in memory permanently while the computer is turned on.

The step-by-step booting process is as follows:

 

Step 1: BIOS and Setup Program

  1. ROM (read-only memory): Permanent and unchanging memory.
  2. BIOS (basic lunar/output system): The part of the system software that includes the instructions that the computer uses to accept input and output.

Step 2: The Power-On-Self-Test (POST)

  1. POST (power-on- self-test): A series of tests conducted on the computer’s main memory, input/output devices, disk drives, and the hard disk.
  2. BIOS conducts Power-On-Self-Test to check the input/ output system for operability.
  3. The computer will produce a beeping sound and an error message will appear on the monitor if any problems are encountered.

 

Step 3: The Operating system (OS) Loads

BIOS searches for the operating system.

  1. Settings in CMOS: complementary metal-oxide-semiconductor determine where to look for the operating system.
  2. The operating system's kernel is loaded into the computer’s memory.
  3. The operating system lakes control of the computer and begins loading system configuration information.

 

Step 4: System Configuration

  1. Registry - Database to store information about peripherals and software.
  2. Peripheral — Device connected to a computer.
  3. Driver — A utility program that makes peripheral devices function properly
  4. The system is configured from the operating system’s registry.
  5. Drivers are loaded into memory.

 

Step 5: System Utility Loads

  1. System utilities are loaded into memory.
  2. Volume control
  3. Antivirus software.
  4. PC card unplugging utility

 

Step 6: Users Authentication

  1. Authentication or user login occurs.
  2. User name
  3. Password

The user interface starts, enabling user interaction with computer programs.


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