An operating system is the fundamental basis of all other application programs. Operating system is an intermediary between the users and the hardware.

Operating system controls and coordinates the use of hardware among application programs. The major services of an operating system are −

• Memory management
• Disk access
• Creating user interface
• Managing the different programs operating parallel
• Likewise, it controls and manage the hardware’s working

Applications of Operating System

Following are the major applications of an operating system −

·        An operating system is accountable for the formation and deletion of files and directories.

·        An operating system manages the process of deletion, suspension, resumption, and synchronization.

·        An operating system manages memory space by allocation and de-allocation.

·        An operating system stores, organizes, and names and protects the existing files.

·        Further, an operating system manages all the components and devices of the computers system including modems, printers, plotters, etc.

·        In case, if any device fails, the operating system detects and notify.

·        An operating system protects from destruction as well as from unauthorized use.

·        An operating system facilitates the interface to user and hardware.

Types of Operating System

Following are the major types of operating system −

• Disk Operating System (DOS)
• Windows Operating System
• Unix Operating System

Let us now discuss each operating system in detail.

Disk Operating System

MS-DOS is one of the oldest and widely used operating system. DOS is a set of computer programs, the major functions of which are file management, allocation of system resources, providing essential features to control hardware devices.

DOS commands can be typed in either upper case or lower case.

Features of DOS

Following are the significant features of DOS −

• It is a single user system.
• It controls program.
• It is machine independence.
• It manages (computer) files.
• It manages input and output system.
• It manages (computer) memory.
• It provides command processing facilities.
• It operates with Assembler.

Types of DOS Commands

Following are the major types of DOS Command −

·        Internal Commands − Commands such as DEL, COPY, TYPE, etc. are the internal commands that remain stored in computer memory.

·        External Commands − Commands like FORMAT, DISKCOPY, etc. are the external commands and remain stored on the disk.

Windows Operating System

The operating system window is the extension of the disk operating system.

It is the most popular and simplest operating system; it can be used by any person who can read and understand basic English, as it does not require any special training.

However, the Windows Operating System requires DOS to run the various application programs initially. Because of this reason, DOS should be installed into the memory and then window can be executed.

Elements of Windows OS

Following are the significant element of Windows Operating System (WOS) −

• Graphical User Interface
• Icons (pictures, documents, application, program icons, etc.)
• Taskbar
• Start button
• Windows explorer
• Mouse button
• Hardware compatibility
• Software compatibility
• Help, etc.

Versions of Windows Operating System

Following are the different versions of Windows Operating System −

Version	Year	Version	Year
Window 1.01	1985	Windows XP Professional x64	2005
Windows NT 3.1	1993	Windows Vista	2007
Windows 95	1995	Windows 7	2009
Windows 98	1998	Windows 8	2012
Windows 2000	2000	Windows 10	2015
Windows ME	2000	Windows Server 2016	2016
Windows XP	2001

Unix Operating System

The Unix Operating System is the earliest operating system developed in 1970s. Let us consider the following points relating to the Unix Operating System −

·        It is an operating system that has multitasking features.

·        It has multiuser computer operating systems.

·        It runs practically on every sort of hardware and provides stimulus to the open source movement.

·        It has comparative complex functionality and hence an untrained user cannot use it; only the one who has taken training can use this system.

·        Another drawback of this system is, it does not give notice or warn about the consequences of a user’s action (whether user’s action is right or wrong).