A Youngsters Guide

By ISHITA BHOWN

We have moved one step ahead in the arena of student and job-oriented books with the CCL, by enhancing our proven pedagogy to bring together the collective knowledge and wisdom of the world of computers. Books published under this series are specifically designed to engage readers, improve computer skills, and prepare themselves for future success. This comprehensive series with step-by-step instructions and relevant screenshots throughout the text enables readers to have a better understanding of computers. Written in simple and lucid language, without technical jargons, each book of this series is accompanied by an interactive CD/DVD with video tutorials.

This is one book that covers everything a beginner needs to know about computers. You will learn things like setting up a new computer; connecting to the Internet; working with digital media; burning custom CDs; watching movies; using Microsoft Office and other popular software; setting up home networks; keeping PCs running reliably; and protecting them from spam, viruses, and spyware, etc. Packed with relevant screenshots and illustrations, the book is easy to follow, never intimidating, and always helpful. It is an indispensable book for the PC novice.

• Language: English
• Publisher: V&S Publishers
• Release date: Jun 1, 2015
• ISBN: 9789350574041

Book preview

Gadgets

Computers are everywhere - at the workplace, at school, at college and at home. Almost every activity in our life either involves the use of computers or depends on getting information from them. They are primary means of local and global communication for millions of people. Employees use computers to correspond with other employees, students with classmates and teachers, and family members with friends and other family members In addition to sending text-based messages, people use computers to share files, information, pictures, videos and music. Some of the most popular functions of a computer include:

Teaching and training aids

Publishing

Telecommunication, wireless communication, internet, etc.

Entertainment

Healthcare and sports

Design of structures and machines

Audio-video editing

Office automation

Definition of a Computer

An electronic device which can automatically accept and store input data, process it and produce output results by interpreting and executing programmed instructions is known as Computer. Some useful definitions in relation to this are:

Data (input) is a collection of raw material like text, numbers and images.

Information (output) is meaningful processed data.

Instructions are the steps that tell the computer how to perform a task.

History of Computer

Computers were invented because of man's search for a fast and accurate calculating adjacent device. It is believed that Abacus (see Figure) which was used by Babylonians around third millennium BC, was the first computing device used for computation.

Abacus

French philosopher and mathematician Blaise Pascal invented the first mechanical adding machine in 1642. Later in the year 1671, Baron Gottfried of Germany invented the first calculator for multiplication. Keyboard machines were invented in the United States around 1880 and they are still used today.

Father of the Computer

Charles Babbage (1791-1871), a British mathematician and engineer, invented a concept of programmable computer called 'Analytical Engine' for performing basic arithmetic functions for any mathematical problem. He is called the 'Father of the Computer'. Though, he was unable to produce a working model of this machine but his efforts were really useful later on.

Charles Babbage

Some well-known earlier computers are:

Generations of Computers

Types of Computers

Computers come in a variety of sizes and ranges of power and capabilities; from giant supercomputers used by universities, government agencies to handheld computers that, as the name implies, can be held in the palm of your hand. Despite the wide variety, all computers operate similarly and perform essentially the same functions. Let us have an overview of the same.

Personal computer: A small, single-user computer based on a microprocessor.

Workstation: A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and, in general, a higher-quality monitor.

Minicomputer: A multi-user computer capable of supporting up to hundreds of users simultaneously.

Mainframe: A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.

Supercomputer: An extremely fast computer that can perform hundreds of millions of instructions per second.

Types of Computer

Personal Computers (PCs)

Personal computers, also known as 'microcomputers' or PCs, are small, relatively inexpensive computers designed for an individual user. Personal computers are based on microprocessor Personal computer technology, which enables the entire processing power of the computer to be located on the silicon microchips. PCs are extremely popular in businesses, in order to perform word processing, spreadsheet, database management and many other tasks. They are also extremely popular in homes for playing computer games and gaining access to electronic mail and the Internet. It is known as personal computer as it is designed to fit on a person's desk.

Personal computer

Actual personal computers can be generally classified by size and case. The case is the metal frame that serves as the structural support for electronic components. Every computer system requires at least one case to house the circuit boards and wiring. There are two basic favours of chase designs-desktop models and tower models-but there are many variations on these two basic types. Then comes the portable computers that are computers small enough to carry. Portable computers include notebook and subnotebook computers, hand-held Computers, palmtops, and PDAs.

Tower Model

The term refers to a computer in which the power supply, motherboard, and mass storage devices are stacked on top of each other in a cabinet. The main advantage of tower models is that there are fewer space constraints, which makes installation of additional storage devices easier.

Raidmax Smilodon ATX mid tower PC case

Desktop Model

A computer designed to fit comfortably on top of a desk, typically with the monitor sitting on top of the computer. Desktop model computers are broad and low, whereas tower model computers are narrow and tall.

Desktop Model

Notebook Computers

Notebook computers, which are also called laptop computers, are small, lightweight personal computers that can even fit inside a briefcase. Because of their small size, laptop or notebook computers have a flat display screen that is smaller than the monitor display.

Notebook Computer

Subnotebook Computers

A portable computer that is slightly lighter and smaller than a full- sized notebook computer. Typically, subnotebook computers have a smaller keyboard and screen, but are otherwise equivalent to

Subnotebook Computer

Tablet Computers

A tablet computer is a small, lightweight, mobile computer which uses touchscreen input rather than a keyboard and mouse. Tablet PCs usually have a screen size of approximately 7 to 10 inches. Most recent in news has been the tablet announced as the world cheapest tablet Aakash by India.

Aakash Tablet (Ubislate)

Classification Based on Operational Principle

Computers can also be classified based on operational principle as analog, digital and hybrid computers.

Analog and Digital Computers

Analog computers process measured data. A speedometer in your car is a common type of analog device.

A digital computer processes discrete data (digits). In this case 0 and 1, PC's are digital computers.

Hybrid Computers

These types of computers are, as the name suggests, a combination of both Analog and Digital computers. The Digital computers which work on the principle of binary digit system of 0 and 1 can give very precise results. But the problem is that they are too slow and incapable of large scale mathematical operation. In the hybrid types of computers the Digital counterparts convert the analog signals to perform Robotics and Process control.

Advantages of a Computer

Speed: When data, instruction and information flow along electronic circuits in computer, they travel at very high speed. Many computers process billions and trillions of operations in a single second.

Reliability: The computer being an electronic component is very reliable as it breaks down rarely.

Consistency: If the same input is provided with same processes the output achieved every time is same, hence this makes the computer truly consistent.

Storage: They can store large amounts of data in their memory and hard disk as well depending on the configuration of the system.

Communication: As computers can communicate with other computers, they can share input or output that can be useful to other systems.

Disadvantages of a Computer

Privacy violation: In the computer world, where everything from credit card reports to medical records and phone numbers to home addresses are stored on the system, there is always risk of privacy violation.

Health Risk: A long continuous use of computers can lead to health issues like backache or disorders in the arm, wrist or eyes. Correct posture and frequent breaks from work can help prevent such risks.

Public safety: From a teenager to an adult, everyone uses the computer in the present world. People like to share their pictures and videos with others over the internet which might be dangerous if falls into the wrong hands. Thus, users need to be careful while sharing any such information over the internet.

Point to Remember

Abacus, which was used by Babylonians around third millennium BC, was the first computing device used for computation.

Charles Babbage is called the Father of the Computer.

Over the years the size, performance, shape and cost of computers have been changing at a phenomenal rate, however, something which is almost still the same is the basic logical structure. It does not matter which computer model we are talking about all the computers perform basic five functions, for converting raw input data into information; which are as follows:

1. Inputting: The procedure of entering data and instructions into the computer system.

2. Storing: Saving data and instructions to make them easily available for initial or additional, as and when required.

3. Processing: It is the process of performing arithmetic operations (add, subtract, multiply, divide, etc.), or logical operations (comparisons like equal to, less than, greater than, etc.) on data, to convert them into useful information.

4. Outputting: The procedure of producing useful information or results for the user, such as a printed report or visual display.

5. Controlling: Instructing the manner and sequence in which all of the above operations are performed.

Any computer system has three important parts:

1. Input Device

2. Central Processing Device / Unit (CPU)

3. Output Device

The Central Processing Unit (CPU) also has three parts:

i. Memory Unit

ii. Control Unit (CU) and

iii. Arithmetic Logic Unit (ALU)

Input Unit

Before any computation is performed on the supplied data, it is necessary that data and instructions are entered in the computer system. This task is performed by the input unit, which links the external environment with the computer system. There are a variety of input devices, such as, keyboard, mouse, joystick, track pad, graphics tablet, scanner, etc.

However, regardless of the form in which they receive their inputs, all input devices must transform the input data into the binary codes, which the primary memory of a computer is programmed to accept. This transformation is accomplished by units called input interfaces. Input interfaces are designed to match the special physical or electrical features of input devices, to the requirements of a computer system.

Output Unit

It supplied the information derived from data processing, to the outside world. You can say that the task of an output unit is just the opposite of that of an input unit. Hence, it connects the computer with the external environment. As has been mentioned earlier, computer works with binary code, the results produced are also in the binary form. Therefore, they must be converted to human readable form before they are supplied to the outside world. This job is executed by output interfaces. Output interfaces are designed in such a way that they match the special physical or electrical features of output devices (terminals, printers, etc.) to the requirements of the external environment.

Storage Unit / Memory

Before actual processing starts, the data and instructions, which are entered into the computer system through input units, have to be stored inside the computer. In the similar fashion, the results obtained by the computer after processing, must be kept inside the computer system, before being passed on to the output units. Moreover, the intermediate results produced by the computer, must also be retained for ongoing processing. To cater to all these needs, the storage unit of a computer system is designed.

Types of Storage

Primary Storage

Primary Storage, also referred to as computer memory, is used by the CPU (Central Processing Unit) of a computer to continuously read and execute programming instructions. Also it reads and writes data from/to the file store in the Secondary Storage of the computer. This storage is accessible directly by the CPU. Typical examples of Primary Storage types are RAM (Random Access Memory), ROM(Read Only Memory), etc.

Secondary Storage

Secondary Storage refers to non-volatile data storage which is only accessible via primary storage devices using I/O (Input/Output) channels or device drivers. Typical examples of Secondary Storage are hard disks, floppy disks, optical storage devices (such as CD, DVD, etc.), flash memory (such as USB [better known as Pen Drives].)

Tertiary Storage

In Tertiary Storage or Tertiary Memory, a robotic arm inserts and removes the removable mass storage media into storage devices according to the system’s demands. This stores information that is infrequently accessed. These types of storage devices are much slower than secondary storage. Tertiary Storage is widely used in large data stores and is accessed without human operators. Example of this storage system is optical jukeboxes.

Off-line storage

Off-line storage or disconnected storage is a computer data storage on a medium or a device that is not under the control of a processing unit. The medium is recorded in a secondary or tertiary storage device, and then it is removed or disconnected. This type of storage system must be inserted or connected by a human operator before a computer can access the information.

Hardware Components of a Computer System

The hardware are the parts of a computer itself including the Central Processing Unit (CPU) and related microchips and micro-circuitry, etc. Other parts are called peripheral devices which include mouse, printers, modems, scanners, keyboards, monitors, drives (foppy, hard, CD, DVD, etc.), etc.

Central Processing Unit: The Central Processing Unit (CPU) also known as the processor is the heart, soul and brain of the computer. In a microcomputer, the entire CPU is on a tiny chip called a microprocessor. Currently the Pentium processor, made by Intel, is the most common CPU though there are many other companies that produce processors for personal computers like Motorola which is used in Apple computers.

Every CPU has two basic parts, the Control Unit and the Arithmetic Logic Unit.

Control Unit (CU): All the computer’s resources are managed from the control unit. It is the logical hub of the computer. The CPU’s instructions for carrying out commands are built into the control unit. Before a program can be executed, every command in it must be broken down into instructions that correspond to the ones in the CPU’s instruction set. When the program is executed, the CPU carries out the instructions, in a particular order. Although the process is complex, the computer can accomplish it at an incredible speed, translating millions of instructions every second.

Arithmetic Logic Unit (ALU): As computers store all the data as numbers, a lot of the processing that takes place involves comparing numbers or carrying out mathematical operations. In addition to establishing ordered sequences and changing those sequences, the computer can perform two types of operations: Arithmetic Operations and Logical Architecture of a Computer Operations. Arithmetic operations include addition, subtraction, multiplication, and division. Logical operations include comparisons, such as determining whether one number is equal to, greater than, or less than another number. Many instructions carried out by the control unit involve simply moving data from one place to another - from memory to storage, from memory to the printer, and so forth. However, when the control unit encounters an instruction that involves arithmetic or logical operation, it passes that instruction to ALU. The ALU includes a group of registers (high-speed memory locations), built within the CPU, that are used to hold the data currently being processed.

Types of Microprocessor (CPU)

Following series of microprocessor have been released by Intel over the year:

Professional Series (Now a days known as Pentium series of processor)

Home Series (Known as Celeron)

Server or Big Size Computer Series (Known as XEON series of processor).

Intel has released many processor in professional series such as 8088, 8036, 80286, 80386, 80486, Pentium Pro, Pentium I, Pentium II, Pentium III, Pentium IV and Pentium Dual Core.

Input Devices

Any electromechanical device that accepts data from user and then translates it into computer understandable form is called input device. There are a variety of inputs units available for use by the computers. Some of them are general purpose that is they may be used by any computer. Various types of input devices along with their use are described below:

Keyboard

The most common device for data input device is the QWERTY keyboard (so named because of the order of the first few characters on the top row of letters reading from left to right.) This is now the standard layout for keyboards in most countries of the world. The Computer continuously scans the keyboard and when a key is pressed, a signal is sent to the CPU using the code for the particular character represented by the key.

The Mouse

A mouse is used to input data in two different ways. Firstly, as the mouse is moved, a ball underneath it revolves and this movement is detected by sensors which relay the data to the CPU. Secondly, buttons on the mouse act in a similar way to that of the keys on a keyboard. When they are pressed, the code for the relevant control is sent to the CPU.

Trackball

It is also a pointing device just like ball-mouse. But here the ball is placed on the top (it was on the below part of the mouse). To move the cursor on the screen the ball is rolled with hand. As here just the ball needs to be moved and not the complete body holding it so less space is required for operation.

Joystick

It is a pointing device which works on the principle of trackball. The ball is placed on a stick in order to make it easier to move. The stick can be moved forward or backward or left or right. Mainly usage of joysticks includes video games and remote control of industrial robots.

Pens

With a pen-based system, you use an electronic pen called stylus to write on the screen and choose commands. Pens are common input devices for handheld computers, like personal digital assistants (PDAs) and tablet PC for collecting database. Pens are handy for making notes or selecting commands, not for inputting a lot of text.

Touch Screens

Touch-screen systems accept input directly through the monitor. They use sensors to detect the touch of a finger. They are useful where environmental conditions prohibit the use of a keyboard or mouse. Touch-screen systems are useful for selecting options from menus. They are useful for ATM, information centre like railways, departmental stores, etc.

Image Scanners

Image scanner converts any printed image into electronic form by shining light onto the image and sensing the intensity of light reflection at every point. Thus they digitize printed images for storage and manipulation in a Computer.

Colour scanners use filters to separate the components of colour into the primary additive colour (RGB). After scanning, we can use photoshop application to change the properties of picture like adjusting contrast, changing colour, etc.

Optical Character Reader (OCR)

In OCR, the scanner is equipped with character recognition software which converts the bitmap image of character to equivalent ASCII code. Image is first stored as bit map. A bit map is group of dots; each dot is represented by one or more bits. OCR translates the array of dots into letters and numbers. For that, it looks at each character and tries to match the character with its own assumption.