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Lesson Note

ii) The second objective of an operating system is to provide an interface to the user through which the
user can interact with the computer.
A user interface is a software component which is a part of the operating system and whose job is to
take commands or inputs from a user for the operating system to process.

There are different types of user interfaces each of which provides a different functionality. Some
commonly used interfaces are:
i) Command based interface
ii) Graphical User Interface
iii) Touch-based Interface
iv) Voice-based Interface
v) Gesture-based Interface

Command based interface
Command-based interface requires a user to enter the commands to perform different tasks like
creating, opening, editing or deleting a file, etc. The user has to remember the names of all such
programs or specific commands which the operating system supports.
The primary input device used by the user for command based interface is the keyboard. Command
based interface is often less interactive and usually allows a user to run a single program at a time.
Examples- MS-DOS and Unix.

Graphical User Interface
Graphical User Interface (GUI) lets users run programs or give instructions to the computer in the form
of icons, menus and other visual options.
Icons usually represent files and programs stored on the computer and windows represent running
programs that the user has launched through the operating system.
The input devices used to interact with the GUI commonly include the mouse and the keyboard.
Examples- Microsoft Windows, Ubuntu, Fedora and Macintosh

Touch based Interface
Today smartphones, tablets and PCs allow users to interact with the system simply using the touch
input.
Using the touchscreen, a user provides inputs to the operating system, which are interpreted by the OS
as commands like opening an app, closing an app, dialing a number, scrolling across apps, etc.
Examples- Android and iOS. Windows 8.1 and 10 also support touch-based interfaces on touchscreen
devices

Voice based interface
Modern computers have been designed to address the needs of all types of users including people with
special needs and people who want to interact with computers or smartphones while doing some other
task.
For users who cannot use the input devices like the mouse, keyboard, and touchscreens, modern
operating systems provide other means of human-computer interaction.
Commands of voice-based OS make a computer work in the desired way.
Example- iOS (Siri), Android (Google Now or “OK Google”), Microsoft Windows 10 (Cortana) etc

Gesture based Interface