COMPUTER FUNDAMENTAL NOTES IN ENGLISH (SATISH KUMAR BARANWAL); Easy notes on Computer Fundamental.

What is Computer?

By Satish Kumar Baranwal

Computer is an electronic machine that takes data and instructions, processes data according to the given instructions, gives results and stores them for later use.

What is a computer - Define computer - Computer Definition

Today, computers are being used in every field of life. It can be used for different tasks.
It is used for data processing. It is used to calculate or perform some mathematical work. It can be used for word processing, record keeping, listening music, playing computer games etc. Above all, it is being used to access and use Internet, a huge source of information.

What are Characteristics of Computer

Following are the important characteristics of a computer:

1. Speed

Computers work at a very high speed. They are much faster than humans.
 A computer can perform billions of calculations in a second. Computer speed is measured in Mega Hertz (MHz).

2. Storage

A computer can store large amounts of data permanently. 

3. Processing

A computer can process the given instructions for processing of data. It can perform different types of processing like addition, subtraction, multiplication and division. 

4. Accuracy

Accuracy means the capability to provide results without any errors. Computer can process large amounts of data and produce 100% accurate results. 

5. Recalling

A computer can recall the stored data and information at any time, as and when required. 

6. Cost Reduction

Computer can reduce cost. We can do a work in less time and cost by computer. A single person, with computer, can do work of many people in an office.

8. Versatile

A computer can perform different types of tasks. We can use a computer in educational institute, in hospital, bank or at home. Computers are being used in banks industry, medical, science and engineering fields.

9. No Feelings

Computer has no feelings. It cannot be affected by sorrows and happiness.

10. No Intelligence

Computer itself is not intelligent. It only follows the given instructions. If a computer is given a program for addition, it cannot perform subtraction by itself.

What are the basic units or components of a computer

1. Input Unit

2. Output Unit

3. Central Processing Unit (CPU / Processor)

4. Memory Unit

5. Storage Unit

1. Input Unit

Input unit consists of input devices. Input devices are used to enter data and instructions into computer memory. Examples of input devices are Keyboard, mouse, joystick and microphone etc.

2. Output Unit

Output unit consists of output devices. Output devices are used to show results produced by computer after data processing. Examples of output devices are Monitor, Printer, plotter and speaker etc.

3. Central Processing Unit

Central processing unit is also called CPU or Processor. It is the brain of the computer. It performs data processing. It controls overall operations and components of the computer. 

4. Memory Unit

Memory unit consists of memory devices to store data . For Example RAM is most common example of memory.

5. Storage Unit

Storage unit consists of storage media. Storage media are used to store large amounts of data permanently. Examples of storage media are Hard disk, CD, DVD and Zip disk etc.

What are Different Types of Computer

Computers can be divided into the following 3 types on the basis of their working mechanism:

1) Analog Computers

2) Digital Computers

3) Hybrid Computers

1. Analog Computers

Analog computer is used to measure continuous values. It measures a physical property like voltage, pressure, speed, time and temperature. An analog computer takes input in analog form and gives output in analog form.
Its output is usually displayed on a meter or scale. Analog computer has low memory and fewer functions. Analog computer is mainly used in the field of engineering and medicine. Examples include:

Examples of Analog Computers include:

1. Thermometer
2. Speedometer
3. Analog clock

2. Digital Computers

A digital computer works with digital data. Digital computer uses binary number system. Binary number system consists of only two digits 0 and 1. A digital computer represents data in digital signals. A 0 represents OFF and a 1 represents ON. Digital computer performs arithmetic and logical operations on data. It gives output in digital form.
Digital computers are very fast. These computers can store results. They have large Memory(that is data storing capacity). Today most of the computers used in offices and homes are Digital computers.
Examples:

1. Personal Computer-(also called PC or Micro Computer)
2. Digital Score board
3. Digital watch

3. Hybrid Computers

A hybrid computer is a combination of both analog and digital computer. Hybrid ccomputer can handle both analog and digital data. A hybrid computer combines the best characteristics of both the analog and digital computer. It can accept data in both analog and digital form.
Examples:

1. Hybrid computer devices are used in hospitals that may calculate patient's heart function, temperature and blood pressure etc. This calculation may be converted into numbers and shown in digital form.

For example,

 The Vital Signs monitoring unit also called VSM in short. It has Blood Pressure   monitor, ECG monitor, respiratory monitor, and is used for monitoring anesthesia.

2. Hybrid computers are also used in spaceships and missile system.
3. Hybrid Computer Machines are generally used in scientific applications
4. Hybrid computers are used for controlling industrial processes. 

Write a note on Classification of Computers

Q. Write a note on Classification of Computers   OR Explain Types of computer on the
basis of Size, Shape and Resources. OR How digital computers are classified?

Classification of Computers
Computers are classified on the basis of size, speed and price as under:
•    Microcomputer or Personal Computer
•    Mini Computer
•    Mainframe Computer
•    Super Computer
1. Micro Computers

Desktop Model computer

Micro computer is also called personal computer. It was introduced in 1970. It contains  input devices, output device, storage device, memory and processor. It is used by one person at a time. Examples of personal computers are PC and Apple Macintosh. The major types of personal computers are desktop computer and portable computer.
Desktop Computers
These computers can easily fit on a table or desktop, hence the name. These computers come in two models or casings. In Desktop model, the system unit is placed on the desktop or table. Monitor is placed on the system unit. In Tower model, both monitor and system unit are placed on the table.

Tower Model computer

Portable Computer
Portable is a personal computer that can be carried from one place to other easily. Notebook computer and handheld computer (smart phone) are examples of portable computers. Notebook computer is also called laptop computer. Laptop computers are very small in size and can be placed easily on lap.

Lap top computer or notebook computer

Hand held computer

Handheld Computers (like smart phone) are also potable. Handheld computer is also known as palmtop computer. It easily fits in the hand of the user.
Uses of Micro Computer
The PC is the most common type of computer used in the office. It is now widely used in many homes. These are also used for business and engineering application.
2. Mini Computers
Mini computers were introduced in the 1960s. 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.

Picture for a note on classification of computers (Mini computers)

Mini computer can serve up to 4000 connected users simultaneously. It is normally accessed by users via personal computer or terminal. A device with a monitor and keyboard is called terminal. It is also known as dumb terminal. It has no processing power and cannot work as stand-alone computer. Examples of mini computers are:
•     VAX-8800
•     AS 400.

Uses of Mini Computers
Mini computers are often used by small and medium-sized companies to provide centralized store of information.
3. Mainframe Computers
Mainframe computers were introduced in 1975. A mainframe computer is a very large computer in size. It is more powerful than mini computer. It consists of multiple processors. It is designed to perform multiple tasks for multiple users at the same time. Mainframe computers can serve up to 50,000 users at the same time.

Picture for a note on classification of computers (Main Frame computers)

The users access a mainframe computer through terminal or personal computer. A typical mainframe computer can execute 16 million instructions per second. Examples of mainframe computers are
•     NEC 610
•     DEC 10
Uses of Mainframe Computers
Mainframe computers are used in large organizations. For example, airlines use these computers for ticket reservation system. NADRA - The Computerized National Idenity Card Issuer in Pakistan - uses mainframe computers to maintain the information of population.
4. Super Computers
Super computers were introduced in 1980s. Super computer is the fastest computer. Super computer is the biggest in size and the most expensive in price than any other computers.

Picture for a note on classification of computers (Super computers)

It is the most sophisticated, complex and advanced computer. It has a very large storage capacity. It can process trillions of instructions in one second. Super Computer is the fastest and most powerful computer of a time. Supercomputers are very
expensive. Supercomputers are used for highly calculation-intensive tasks. Super computers are used for specialized applications that require immense amounts of mathematical calculations. Supercomputers were designed primarily by computer scientist - Seymour Cray at Control Data Corporation (CDC).
Uses of Super Compters include:
1. Weather forecasting,
2. animated graphics like in Hollywood movies,
3. fluid dynamic calculations,
4. nuclear energy research,
5. space science
6. Weapon and missile design
7. and petroleum exploration etc.
Today, supercomputers are produced by traditional companies such as Cray, IBM and Hewlett- Packard, who had purchased many of the 1980s companies to gain their experience. Since October 2010, the Tianhe-1A supercomputer has been the fastest in the world; it is located in China.
The main difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a single program as fast as possible, whereas a mainframe uses its power to execute many programs concurrently. The modern super computer consists of thousands of microprocessors. Super computer uses high-speed facilities such as satellite for online processing.

Examples of super computers are CRAY-XP, ETA-10, and Deep Blue and above all Todays number one super computer is Tianhe-1A supercomputer of China. Aircraft companies use super computer to simulate aircraft and check its performance. Many  Hollywood movies use it for animation purposes.

The Concept of a Computer System

A system is a set of inter related components that work together to fulfill a purpose. For example a Road Transportation System will consist of the parts - roads, vehicles- trucks, buses, vans, cars etc, passengers, the staff for ticketing and maintenance of vehicles and roads etc. And the transportation system will fulfill the purpose of carrying of passengers and luggage from place to place. Similarly, a computer system consists of many components that work together to fulfill the purpose of data processing. A Computer system consists of the following four parts:

1.    Hardware
2.    Software
3.    Data
4.    User


1.    Hardware
The mechanical devices that makeup the computer are called HARDWARE, for example, Keyboard, hard disk, monitor, processor and mother board etc. Hardware are physical devices. They can be touched. Hardware device are interconnected and perform input, processing and output operations.

2.    Software
Software is the set of instructions given to computer to perform a task. Software tells the computer what to do. System Software like operating systems are used to

manage components and operations of computer. Application Software like MS Word and MS Excel are used to solve specific problems of the user, for example creating documents or preparing Student Result Sheet etc. Thousands of different software are available for use on PC.

3.    Data
Data is the collection of raw facts. Data processing is the primary job of a computer. Computer processes data in many ways to convert them into useful information. Processed data becomes information. For example, during census, data of all citizens is collected. Census data is used to get report/information about total population of a country and literacy rate etc.

4.    Users
People that operate the computer are called computer operators or computer users. Users use computer to solve different problems. For example, in a college a computer operator in Examination Section will feed marks obtained by students in a software like MS Excel. He/ She will perform certain functions and formulae to calculate percentage and grade of each student and prepare a result sheet. This result sheet will show the marks obtained, percentage, grade and Fail/ Pass status of every student.

COMPUTER HARDWARE
You learned earlier that a computer has electronic and mechanical parts known as hardware.
Hardware also includes input devices, output devices, system unit, storage devices and
communication devices. Without these components we would not be able to use the computer.
Input Devices –
 An input device is any hardware component that allows you the user to enter data into the computer.
There are many input devices. Six of the most widely used input devices are:
1. A keyboard -- You use the keyboard to type letters,
numbers,and symbols into the computer.
2. A Mouse --The mouse is a pointing device that has a pointer
that changes into different shapes as you use the mouse.
You click the mouse by pressing and releasing the button.
This action allows you to enter data when using a mouse.
3. A Scanner -- This input device copies from paper into your computer.
4 . A Microphone -- The microphone is usually used for voice input into the computer.
5. A Digital Camer -- The digital camera allows you to take pictures that you can input into your computer. 
6. A PC Video Camera -- The PC video camera allows you take both video
and still images that you can input onto your computer.

Output Devices:-
 An output device is any hardware component that gives information to the user.
Three commonly used output devices are as follow:
 1. A Monitor -- This output device displays your information on a screen,
2. A Printer -- This output device prints information on paper.
This type of printed output is called a hard copy
3.A Speaker -- Sound is the type of output you will get from a speaker. 

COMPUTER SOFTWARE
The computer will not work without software. Software also call programs are the instructions that tell the computer what to do and how o do it. The two main categories of software are system software and application software. The system software also called the operating system (OS) actually runs the computer. This software controls all the operations of the computer and its devices. All computers use system software and without the system software the application software will not work. The most common OS on a PC is the Windows operating system and for the Mac computer it would be the Mac operating system.
Application software is a program that allows users to a specific task on the computer. There are a number of different types of application software available to do many of the tasks we do daily. Four examples of common application software and what they are used for are:
Word Processing Application: One word processing program is Microsoft Word. This program allows you to type letters, assignments and do any other written activity on the computer.
Spreadsheet Application: Microsoft Excel is an example of a spreadsheet program. One can use this program to create charts and do calculations.
E-mail Application: Outlook Express is an e-mail program that allows you to receive and send e-mails.
Internet Application: Internet Explorer is a program that allows you to get connected to the Internet and look at Web sites like the one you are reading now.
It is important to note that when you buy a computer the computer comes with the operating system and some software already installed. You may have to buy more software and install them on the computer. Install means to load the software onto the hard disk of the computer so that you can run or use the software.
Like any other equipment the computer needs to be cared for; let us discuss how we should go about caring for our computer.

STORAGE MEDIA
Storage keeps data, information and instructions for use in the future. All computers use storage to keep the software that makes the hardware work.
As a user you store a variety of data and information on your computer or on storage media. Storage media are the physical materials on which data, information and instructions are kept. When a user saves information or data to a storage medium he or she is storing a file, and this process is called writing.
When the file is opened the process is called reading. Common storage media are:
Hard Drive: This storage medium which looks like the one below, is a hard drive. This medium comes with the computer and is always inside the computer.
It stores all the programs that the computer needs to work. In addition users store their data and information on the hard drive.

Floppy Disk: This storage medium is considered to be a portable storage medium. You put it into the computer save your information on it, take it out, and take it with you wherever you go.

CD&DVD: These types of storage media hold much more information than a floppy disk. They are also considered portable storage. These types of storage media come in different forms. This means that there are CDs and DVDs that you can only save information on but you cannot erase the information. In addition there are those that can both save information on and erase the information you have saved.

USB Flash Drive: This is a storage medium that is very easy to carry around and it also holds more data than a floppy disk. As you can see from the picture below it is very small when compared with the others.

COMPUTER CARE
Taking care of your computer is just as important as taking care of your books. Both the internal and the external parts of the computer have to be cared for. Scanning, defragging and reformatting are some of the activities performed to clean up the hard drive. These activities are best left to a grown up and such you should not attempt them. However, there are certain tasks you can perform to ensure you computer is clean; here are a few:
Keep Dust Away: Dust your computer to keep it free of dust and dirt.
Keep Food Away: Do not eat or drink while working on the computer.
Use Clean Hands: Make sure your hands are clean before you type on the keyboard of click the mouse.
Treat With Respect: If you are having problems with your computer, ask for help. Do not bang or hit the computer.
Keep Off: Seeing that the computer is connected to electricity, this means that lightning could be conducted to your computer through the electrical connection. For this reason it is best not to use your computer during a storm.
Stop Virus Attact: A computer virus is a program written by a person on purpose to harm other peoples’ computers. A computer virus is passed from one computer o another when you share and download files without the protection of an antivirus software. For this reason you should get permission before downloading files.
Handle With Care: The way you handle your CDs will determine how log they will last. Always hold the CD correctly as shown in the picture below.