What is an operating system

An operating system is a program designed to run other programs on a computer. A computer’s operating system is its most important program. It is considered the backbone of a computer, managing both software and hardware resources. Operating systems are responsible for everything from the control and allocation of memory to recognizing input from external devices and transmitting output to computer displays. They also manage files on computer hard drives and control peripherals, like printers and scanners.

The operating system of a large computer system has even more work to do. Such operating systems monitor different programs and users, making sure everything runs smoothly, without interference, despite the fact that numerous devices and programs are used simultaneously. An operating system also has a vital role to play in security. Its job includes preventing unauthorized users from accessing the computer system.

There are multiuser, multiprocessing, multitasking, multithreading, and real-time operating systems. A multiuser operating system enables multiple users to run programs simultaneously. This type of operating system may be used for just a few people or hundreds of them. In fact, there are some operating systems that are used to allow thousands of people to run programs at the same time.

A multiprocessing operating system allows a program to run on more than one central processing unit (CPU) at a time. This can come in very handy in some work environments, at schools, and even for some home-computing situations. Multitasking operating systems work a little differently; they make it possible to run more than one program at a time. Multithreading operating systems are even more different, allowing varied parts of one program to be used simultaneously.

Real-time operating systems are designed to allow computers to process and respond to input instantly. Usually, general-purpose operating systems, such as disk operating system (DOS), are not considered real time, as they may require seconds or minutes to respond to input. Real-time operating systems are typically used when computers must react to the consistent input of information without delay. For example, real-time operating systems may be used in navigation.

All Version of Windows

List of Windows Client OS with their Version Numbers

Operating System	Version Number
Windows 1.0	1.04
Windows 2.0	2.11
Windows 3.0	3
Windows NT 3.1	3.10.528
Windows for Workgroups 3.11	3.11
Windows NT Workstation 3.5	3.5.807
Windows NT Workstation 3.51	3.51.1057
Windows 95	4.0.950
Windows NT Workstation 4.0	4.0.1381
Windows 98	4.1.1998
Windows 98 Second Edition	4.1.2222
Windows Me	4.90.3000
Windows 2000 Professional	5.0.2195
Windows XP	5.1.2600
Windows Vista	6.0.6000
Windows 7	6.1.7600

windows 8                                              ------------