Computers Notes

Basics of Hardware and Software in computer

Basics of Hardware and Software 

A computer is a combination of hardware and software. These two work combinedly and make computer do for what it is instructed. 


It refers to the physical components of a computer that can be touched and seen. Monitor, Keyboard, Hard Disk Drive, Mouse, Printers, Memory, Motherboard, Graphic Cards, Sound Cards etc., are some hardware devices. By the use of these hardware devices, it made very easy for the computer for processing its data, store and retrieve. 

Some hardware devices are as follows :

Input Devices (Unit) 

Output Devices (Unit) 

Central Processing Unit (CPU) 

Computer Memory/Memory Unit

  • Input Devices 

An input device is a hardware device that sends data into the computer system. These devices are used to input (or enter) data and instructions into the computer system. All instructions are accepted by the CPU through electrical pulses from various kind of input devices. Some of the input devices are Keyboard, Pointing Devices, Scanner, MICR, OCR, OMR, Barcode Reader, Microphone (Mic), Web Camera, Digital Camera, Biometric Sensor, Smart Card Reader which explained as follows


It is the most commonly used input device which uses an arrangement of buttons and keys. Both data and program can be entered into the computer through the keyboard. It is an essential device for interactive processing because the user can easily issue commands to receive the data response immediately on the computer screen.

Types of keys on Keyboard

Alphanumeric Keys All of the letters and numbers on the keyboard are A-Z and 0-9.
(ii) Punctuation Keys Such as comma,period, semicolon, brackets, parenthesis and so on.
(iii) Special Keys Such as Control keys,Arrow keys, Caps lock key, Delete key,Alt key, Shift key etc.
(iv) Function Keys Keys labeled F1 toF12. These keys have different meanings depends on running program.
➥ Note Shift, Ctrl and Alt keys are also known as modifier keys.


Pointing Devices
A pointing device is used to communicate with the computer by pointing to the locations on the monitor.
It can also be used for
● sending command signals to the computer.
● selecting items on the screen.
● selecting commands from command menu.
● drawing graphics, sketches, etc.
Some commonly used pointing devices are mouse, joystick, light pen, graphics tablet,touch screen and trackball.

Mouse It is a pointing device that allows to control the movement of pointer (also known as mouse pointer) on screen. Mouse performs various functions by detecting two-dimensional motion relatively to its supporting surface.Generally, a mouse has two buttons-right button and left button. Mouse also includes a scroll wheel between these two buttons to scroll down the application window and their
contents also. These are three types of mouse as – Wireless mouse, Mechanical mouse, Optical mouse.

There are four actions of mouse as follows :
(a) Click or Left click selects an item
on the screen.
(b) Double click is used to open a
document or program.

(c) Right click displays a list of commands on the screen. Right clicking is used to access the
properties of selected object.
(d) Drag and Drop is used to move an item on the screen.


It is a pointing device that moves in all directions and controls the movement of the cursor. A
joystick is similar to a mouse excepts that the movement of cursor on screen stops working as soon as user stop moving the mouse.But with a joystick, the pointer continuous moving in the previously
pointing direction.Commonly, joysticks are used for playing computer games like flight simulators but occasionally used for CAD/CAM systems and other applications.


Light Pen

It is a handheld electro-optical pointing device, which is used for making drawings, graphics
and for menu selection. It senses the light from the screen when it becomes closer and generates a
pulse. Light pen is used especially in Personal Digital Assistants (PDA). It is very useful in identifying a specific location on the screen.

Graphics Tablet

A graphics tablet (or digitisers, digitising tablet, or simply tablet) is an input
device that consists of an electronic writing area and a special pen that works with it.It allows artists to create hand-made images and graphical images with motion and action, similar to the way a person
draws images with pencil and paper. When user draws anything on the tablet with the special pen, the drawing appears on the screen. Graphics tablet may also be used to capture data or
handwritten signatures.

 Touch Screen

It isan electronic visual display that can detect the presence and location of a touch within the display area. The term touch screen generally refers to touching the display of the device with a finger or hand.The touch screen sends a signal to the computer. This signal gives the location on the screen, which has been touched. Touch screen is quick and simple to use. Generally, smartphones have a
high-resolution capacitive touch screen.

There are different types of touch screens available with electronic devices
like capacitive touch screen, resistive
touch screen and gorilla glass touch
screen, etc.


It is designed for computers, generally serves as mouse replacement. It is primarily used to move the cursor on the screen.The trackball has a ball on its top. Trackball can be rolled with
fingers and the internal rollers sense the motion, which is transmitted to the computer.
Trackballs are common on CAD workstations and sometimes seen on computerised special purpose work stations, such as the radar consoles in an air-traffic control room or sonar equipment on a ship or submarine.

It is an input device that makes copies and reproduces text and images and convert
it into a digital file, allowing the computer to read or display the scanned object. Scanners can be
used for storing the documents in their original form that can be modified and manipulated later on. It is mainly used to convert a scanned document in a digital format. Scanners come in a variety of sizes
from hand held models to desktop models as Handheld scanners, Flatbed scanners and Drum scanners.

MICR (Magnetic Ink Character Recognition)

It is a character recognition technology which is primarily used by the banking industry to facilitate the processing of cheques. This technology allows the computer to read information (such as account numbers) on printed documents.

MICR can read upto 2400 documents/min.The MICR coding system contains 14 characters (4 special symbols and 10 decimal digits). So, it can recognise these 14 characters only. The type font E-13 B, a
standard typographical style, is used to print the characters or identification marks.


OCR (Optical Character Recognition) It is used to translate scanned images of handwritten, type-written, 

printed text or special type answer of objective type tests, voting applications and other evaluations studies. 

 Barcode Reader 

It is an input device used for reading printed bar codes (Universal Product Code) available on product to be sold. A barcode reader emits a beam of light, which reflects off the barcode 

image. A light sensitive detector in the barcode reader identifies the barcode image by recognizing special bars at font printed on conventional paper with conventional ink 


OCR is widely used to convert books and documents into electronic files, to computerise a record-keeping system in an office or to publish the text on a website. An optical reader uses photoelectric devices to scan the characters being read and convert the reflected light patterns of the data into binary data suitable for computer input. The normal speed of an OCR is 1500 to 3000 characters per second. 

The technology is being developed for greater accurate recognition and is also known as Intelligent Character Recognition (ICR). 

OMR (Optical Mark Reader) 

OMR is the process of detecting the presence of intended marked responses. OMR is mainly used to detect marks on a paper. It uses a beam of light that is reflected on the paper with marks, to capture presence and absence of data (Marks). 

The OMR reader interprets the patterns of marks into a data record and sends this to the computer for storing, analysing and reporting. OMR is widely used to read the 

converted into a numeric code. A perfect example of a barcode reader is its use in a super market where barcode scanner reads the price of a product. 

A barcode is a machine readable representation of information in the form of stripes of dark and light ink. 

Microphone (Mic)

We can send sound to the computer through a special manual input device called microphone or mic. A mic converts the received sound into computer’s format, which is called Digitised Sound or Digital Audio. To convert a voice into digital form, an additional hardware is always needed which is known as Sound Card. 

Sound is used most often in multimedia, where user can make his/her presentation more attractive using recorded narration, music or sound effects. 

A microphone can be attached to a computer to record sound. Now-a-days, microphones are also being used with speech recognition software. This means that you do not have to type the document, rather just have to speak and the spoken words appear in your document. 


Web Camera (Webcam) 

Webcam is a digital camera attached to computers and can be used for video conferencing or online chatting, etc. It is a video capturing device. Webcams are able to capture full motion videos as well. A webcam connected to a computer allows the user to view either a still picture or motion video of a user or other object. 


Smart Card Reader

It is a device which is used to access the microprocessor of a smart card. There are two kinds of smart cards. Memory cards the cards which contain only .

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button