Input Devices

Anything given to the computer is known as input such as data or instructions. An input device is a hardware component that is used to enter data and instructions into a computer.

1. Keyboard

Keyboard is the most commonly used input device. Data is mostly entered using a keyboard. The buttons on the keyboard are called keys. A keyboard contains over 100 keys.
Keyboard is used to type the following:
* Alphabets (A to Z and a to z),
* Numbers(0 to 9),
* spaces
* symbols like $,# and % etc.


2. Mouse

A mouse is a small, lightweight input device. It is also called pointing device. Mouse is moved on a flat surface to control the movement of the cursor (pointer) on a screen. The mouse is attached to the computer by a cable or wireless connection. A mouse usually has two or three buttons. These buttons are used to perform different tasks. The mouse contains a small ball at the bottom. The movement of the cursor depends on the movement of ball. A mouse is very easy to use. It is mostly used in graphic applications.



3.Track Ball

A trackball can be used as a alternative to a mouse. This device has buttons similar to those on mouse. It has a large rotating ball on the top. The body of the track ball is not moved. The ball is rolled with fingers. The position of the cursor on the screen is controlled by rotating the ball. The trackball takes less space to move than mouse. It is often included in laptop computers.






4.Touch pad/ Track Pad

A touch pad is a small, flat surface over which the user moves his finger. The movement of the finger moves the cursor on the screen. It is also known as track pad. A touch pas also has one or more buttons near it. These button work like mouse buttons. Touch pads are commonly used with notebooks computers





5.Pointing stick

Pointing stick is a pressure-sensitive device. It is similar to a pencil eraser and exists between keys on the keyboard. The pointer on the screen moves when the user pushes the pointing stick. It requires no additional space or cleaning like mouse. Pointing stick is normally used with notebook computers.






6. Graphics tablet

A graphics tablet consists of a flat pad (the tablet) on which the user draws with special pen called stylus. The image is created on the screen as the user draws on the pad. A designer can produce very accurate drawing using graphics tablet. It is also called digitizer.




7.Touch Screen

Touch screen is a video display screen that receives input from the touch of the finger. The screen is covered  with plastic layer. There are invisible beams of infrared light behind the screen. The users enter data by touching icons or menus on the screen. Most touch screen computers use sensor to detect touch of the computer. Touch screen is well suited for simple applications like ATM. It has also become in departmental store and supermarkets.





8.Digital Scanner

Digital Scanner is an input device. It is used to read the pictures and other printed material place on its glass. It reads the pictures, translates it in digital form and stores it in the computer. Digital scanner uses laser technology to read images.







9.Digital Camera

Digital cameras record photographs in the form of digital signal that can be stored in a computer. No chemical-based film is used.Some digital cameras are portable and look similar to traditional film cameras.Other digital cameras are stationary and are connected directed to a computer.







10.Light Pen

A light pen is a hand held pen-like device. It is light-sensitive stylus.It is connected by a wire to the computer.It has a device at the tip that emits light. The pen sends information to the computer when user touches the pen on certain areas of a specially designed screen. Light pen is usually used engineers, graphic designers and illustrations.





11.Joystick

A joystick consists of a base and a stick. The stick can be moved in any direction to move an object around the computer screen. A joystick can perform a similar function to a mouse or trackball. It is often considered less comfortable and efficient. The most common use of a joystick is for playing computer games.

Components of Computer

1. Input Devices

The data or instruction give to the computer is called input. A hardware component used to enter data and instruction into computer is called input device. Most commonly used input devices are Keyboard, Mouse, Microphone, Scanner, PC camera and digital camera.

2. Output Devices

The data Processed into useful information is called output. A hardware component used to display information to the user is called output device. Most commonly used output devices are monitor, printer and speaker.

3. System Unit

System unit is a box  that contains different electronic components of computer system. All computer system have a system unit. The electronic components in the system unit are connected to motherboard. Motherboard is also called system board or  main board. The system unit board is the communication medium for the entire computer system. Important components of system unit are CPU and Memory.

4. Storage Devices

The hardware components used to store data, Instructions and Information permanently are called storage devices. It is called nonvolatile because it contents remain save when the computer is turn off. Some important storage devices are floppy disk drive, zip drive, hard disk drive CD-ROM drive CD-RW drive, DVD-ROM drive etc.

5. Communication Devices

The hardware components used to communicate and exchange data, Instructions and information with other computers are called communication devices. An important communication Device is called modem. It enables the computer to communicate with others computers via telephone line or cable.

Hardware

The physical parts of a computer are called hardware. Hardware can be touched or seen by us.

Different types of hardware components are as follows:

1 Input devices such as mouse, keyboard and joystick etc.

2 The central processor unit (CPU)

3 Output devices such as printer, monitor, speaker etc.

4 Storage devices such as disk drive, hard drive etc.

5 Memory chips such as RAM, ROM etc.

Information Technology

Information technology is the technology that uses computing with high-speed communications links to spread information from one place to another. The interconnection of computer is enables people to send and received information. The communication links are also used to interact with different people in the world. Computer is an important component of information technology. It makes possible to use information technology to solve problems.
The world has become a global village due to advancement in information technology. It means that people living in the world know one another as if they are living in a village. It has become possible due to fast communication links. Information can be transferred from one place to another place easy and quickly.

Classification of Computers

Computers can be divided into the following categories:

2.      Mini Computers

Mini computer is larger and more powerful computer than personal computer. It can execute five million instructions per second. It generally consists of two or more processors. Mini computer is also known as midrange Server. It is normally accessed by users through personal computer or terminal. A device with a monitor, keyboard and memory is called terminal. Mini computer are often used by small and medium-sized companies or departments. Examples of mini computers are IBM System 360 & AS 400.

3.      Mainframe Computers

A mainframe computer  is a large computer in term of price, power and speed. It is more powerful than mini computer. It consists of multiple processors. It is specially designed to perform multiple intensive tasks for multiple users simultaneously. It can store large amount of data, information and instructions. The users access a mainframe computer through terminal or personal computer. Son and Unisys or leading manufactures of mainframe computers. Mainframe computers are used in large organization such as bank, educational institution and Govt. departments. Examples of mainframe computers are IBM4381 & NEC610 etc.

4.       Super computers

Super computer is the biggest in size and the most expensive in price than any other computers. It is used to perform complex tasks. It has a very large storage capacity. It can process trillions of instructions in one second. The modern super computer consists of thousands of micro processors. An example of a super computer is ASCI white. It contains 8192  CPU and can perform 12 Trillion calculations per second. Super computer is mostly used in weather predictions, weapon design and atomic research etc.

Classification of Computers

Computers can be divided into the following categories:

1. Micro Computers

Microcomputer is also called Personal computers. It was introduse in 1970. It is designed to be used by on person at a time. It consists of one or more input device, output device, storage device, memory and processor. It generally consists of single processor. Some PC's may have two processors. Most commonly used personal computers are PC and Apple Macintosh. Major types of personal computer are desktop computers and portable computer

i. Desktop Computers

                                                                                          Desktop computers are the most common type of personal computer.It is designed in a way that all its components fit on a desk or table. In one model,the system unit is placed  horizontally on the desktop or table and monitor is placed on the system unit.In another model, called tower model, both monitor and system unit are placed on the table.The system    unit in tower model is placed vertically.

ii. Portable Computer

Portable is a personal computer that can be carried from one place to other easily.
 Following are two main types of portable computers:

a. Notebook Computers

Notebook Computer is also called laptop computer. It is small in size and can be placed easily on lap. Only one user can use them at a time. It use less power. It can be used using batteries. A laptop computer can perform the same basic functions as a personal computer. Laptop computers are more expensive than desktop computers.

b. Handheld computers

Handheld computer is also known as palmtop computer. It easily fit in the hand of the user. It contains small screen and small keyboard. Handheld often use stylus to enter data. Some handheld computers also support voice input. Handheld computer is not powerful as compare to desktop and notebook computer. Some examples of handheld computers are Personal Digital Assistant (PDA and Web-enabled Cellular Telephone.

Types Of Computer

Computer can be divided into the following types on the basis of their working:

1. Analog Computers

An analog computer does not operate with digital signals. It recognizes data as a continuous measurement of a physical property. Its output is usually displayed on a meter or  graphs. Voltage, pressure, speed and temperature are some physical properties that can be measured in this way. Analog computer has low memory and fewer functions. Analog computer is mainly used in the field of engineering and medicine.

2. Digital Computers

A digital computer works with digits. Everything is described in two states i.e. either on or off. The number 1 represents on and represents the off state.The digital computer are very fast. Digital computers are manufactured in a wide variety sizes, speeds and capacities. Digital computers are commonly used in offices and educational institutions. Apple Macintosh and IBm PC are two important digital computers

3. Hybrid Computer

A hybrid computer is a combination of both analog and digital computers. A hybrid computer combines the best characteristics of both the analog and digital computers. It can accept data in analog and digital form. hybrid computer may calculate patient's heart functions, temperature, blood pressure etc.

Generations of Computer

The development of electronic computer can be divided into generations depending upon the technologies used.
The generations of computer are as follows:

First Generation Computers (1942-1955)

First generation computers were used during 1942-1955. They were based on vacuum tubes. Vacuum tubes were the only electronic component available during those days. Vacuum tube technology made possible to make electronic digital computers. These computers heated  very soon due to thousand of vacuum tubes. They used only machine language. Punch cards were used for input in these computers. Examples of first generation computers are ENIVAC and UNIVAC-1 etc.






Second Generation Computers (1955-1964)

The transistors was used in second generation computers. Transistors are smaller, more reliable and consume far less power as compared to vacuum tubes. Examples of second-generation computers are IBM 7094 series, IBM 1400 series and CDC 164 etc.







Third Generation Computers (1964-1975)
The major invention of third generation computer was the development of IC. IC stands for Integrated Circuit. A single IC chip contains thousands of transistors. The computer became smaller in size, faster , more reliable and less expensive. Some examples of third-generation computers are IBM System/360, UNIVAC 1108 and IBM 370 etc.




Fourth Generation Computers (1975-Present)

The fourth generation computers started with the invention of microprocessor. Microprocessor is a small chip containing thousands of ICs on it. It greatly reduced the size of the computer. The size of modern microprocessor is usually one square inch. It can contain millions of electronic circuits.
The first microprocessor was produced by Ted Hoff in 1971 for Intel Corporation. The name of this processor was Intel 4004. Examples of fourth generation computers are Apple Macintosh adn IBM PC.



Fifth Generation (Present and Beyond)

The 5th generation computers are based on the technique of artificial intelligence (AI). Computers can understand spoken words instructions and imitate human reasoning. The ability to translate a foreign language is also moderately possible with fifth generation computers. Scientists are trying to create a computer with real IQ with the help of advance programming and technologies.

Uses of Computer

A computer is used in every field of life. The use of computer has made different tasks very easy.

Uses Of Computer at home

computer can  be used at home in the following ways:

Home Budget: Computer can  be used to manage home budget.the user can easily calculate expenses and income. The user can make calculations to plan home budget.
Computer Games: Different types of games are available. Many games are available that are specially developed to improve mental capability and thinking power.
Working From Home: People can manage the office work at home.The owner of a company can check the work of the employees from home.
Entertainment: People can find entertainment on internet.They can watch movies,hear songs and download different stuff.They can watch lives matches on internet.
Information: The user can find any type of information from internet you are download books,tutorials and other material to improve your knowledge.
Chatting: You can Chat with your friends on internet.you can also talk with them.Different messages,files and information can be send to them.

Uses Of Computer in Education

Computer can  be used in education in the following ways:

CBT(Computer-Based Training): CBT are different program that are supplied on CD-ROM. Audio and video lectures are recorded on the CDs. CBT is a low cost solution for educating people.It can be used to train a large number of people easily.
Online Education: Many websites provide online Education.The user can download educational material,books and tutorials.Some universities provides online lectures.
Research: Computers are also for research purposes.Different research scientist can share their research using internet. Many websites are developed for research.

Uses Of computer In Industry

Computer can  be used in industry in the following ways:

Automated Production Systems: The car factories assemble cars by computer-controlled robots.These systems work quickly than human beings.
Design Systems:Many products are designed using CAD (Computer Aided Designed).Computers programs are used to design the model of a product on the computer.The actual product is produced after completing the design.

Uses Of Computer in business

Computer can be used in business in the following ways:

Marketing: A business organization can use computers for marketing their products.Computer is used to manage distribution system,advertising and selling activities.
Stock Exchange: Many stock exchanges use computers to conducts bids.The stockbrokers perform all trading activities electronically.It reduces cost.
Banks: The use of computers in banks saves time and provides convenience for customer. Many banks  provide the facility of Automated Teller Machine (ATM) to with draw cash directly from machine.Banks  provide credit card to purchase different items on the internet.Banks use computers to maintain customer accounts.
Departmental Store:  The cashier can enter sales data in computer by using barcode reader. The computers Used this input to calculate bill.

Uses Of Computer in Medical Field

Computer can  be used in medical field in the following ways:

Hospital Administration: A computer can be used for administration of       hospital.We can keep record of different medicines, their distribution and use in wards etc.
Recording Medical History: Computer is used to store medicals history of patients .A doctor can keep record of his past treatment,suggested medicines and results etc.
Monitoring Systems: Many computerized devices are used to monitor the blood pressure, heartbeat and brain of the patients.
Life Support Systems: Life support systems are used to help disabled persons.Many devices are used to help deaf person to hear.

Introduction To Computers

Computer:

Computer is an electronic device that is used to solve various problems according to a set of instructions given to it. A computer can accept data, process data into useful information and store it for later use. Computer word is derived from compute that means to calculate. Computer is used to perform arithmetic  and logical operations Calculation is not the only use of computer. it can be used for different purposes.

Characteristics Of Computer:

Following are The important characteristics of a computer
Speed:    A computer can perform billions of calculations in a second.Computer speed is measured in Mega Hertz (MHZ) or Giga Hertz (GHz).
Storage:     A computer can store large amounts of data permanently. The user can store and type of data such as text, graphics ,audio and video files.
Processing:  A computer can perform different types of processing. It can perform arithmetical and logical  processing.
Accuracy:    Accuracy means to provide results without any errors. A modern computer perfoms millions of operations in one second without any error.
Consistency:    A Computer works in a consistent way. Computer perfoms all jobs with equal attention.
Communication:    A computer can communicate with other computers. Computers can share data , instructions and information.