User talk:Amankhan007ak

INTRODUCTION TO C LANGUAGE '''A Computer Is an electronic computing machine used to solve a large variety of problems related with all the aspects of our life. It consists of hardware and software. the physical components of the computer are known as hardware and software means computer programs. A computer program is a set of instruction written in a programming language to solve a particular Problem and achieve specific results. Any task performed by a computer is controlled by a set of instructions or a computer as a problem-solving tool.'''

INTRODUCTION TO INFORMATION TECHNOLOGY

'''The world is going through an information explosion. This generation of information has required the development of devices that could store this information and process it to obtain knowledge and update it. The human brain is incapable of storing such large amount of information and retrieving it instantly. This resulted in the development of computer. Moreover, the complexities of computational work are time consuming. Computer has freed the man from the bonded slavery of arithmetic. '''

What is Information Technology?

'''Information Technology (IT) is the use of modem technology to aid in storage, processing, analysis and communication of information. Information can be represented in a computer in four different forms as follows:'''

a) Data

'''The first method presents the information in its basic and most elementary form, as a string of characters (letters and numbers). We call this data. An item of data may be a name, a price, a quantity, a code number, etc. By itself an item of data is not of much use. It only makes sense when it is combined with other information.'''

b) Text

'''The second method presents the information written as phrases and sentences. This called text. Although, text is much longer than a basic item of data but it is much more meaningful.'''

c) Image

'''The third method presents the information in pictorial form. This includes charts, graphs, pictures and freehand drawings. This is called image. Information in this form is more comprehensive than an item of data and more meaningful.'''

d) Voice

'''The fourth method presents the information in spoken phrases and sentences. We call it voice. Like text, it is much more meaningful than an item of data.'''

'''Often we use two more of these forms of information to convey a message. Sometimes you have to choose between alternative methods of presenting the same information. You should select the method, which most clearly and accurately represents the aspect of real world you are seeking to convey.'''

The IT Revolution

'''The growth in electronics over the past quarter century has been phenomenal. What we have seen is not an evolution in technology but a revolution. Our society, our businesses, our homes and our leisure activities are being transformed.'''

'''Modern electronics is based upon the microprocessor, one form of microchip, which consists of miniature logic circuits etched onto the surface of a silicon chip. These tiny circuits replace the enormous banks of glass valves used in the earliest computers of the 1940s and 1950s.'''

'''A computer that uses a microprocessor as its central processing unit is known as microcomputer or personal computer (PC). A microprocessor controls the entire operation of a microcomputer. Thus, it is the brain of the microcomputer.'''

'''The early computer processed information in the form of data. Modern computer are more powerful and can handle information in other forms, including graphics and speech. However, the work on the same principles as the early models. The main difference between the computer of 30 years ago and the microchips of today lies in the fact that the latter are very small, very cheap, very reliable and very powerful. In fact, ever since the first chips were made in the early 1960s, their power has increased every year while their cost has decreased. It is this fact, continued over a quarter of a century that has caused the information revolution.'''

'''Microprocessors are now so cheap and so small that they can be incorporated into any device that can benefit from the power of the computer. What this means is that to an increasing extent, appliances are able to control themselves, so that the minimum of human intervention us required. This has had an obvious impact on our lives as it has brought large improvements in efficiency and productivity as well as it has affected our daily life patterns of work and leisure.'''

COMPUTER HARDWARE AND SOFTWARE '''Programs written in a computer’s machine language can be directly executed by the computer’s electronic circuits, without any intervening interpreters or translators. These electronic circuits, along with the memory and input/output devices, form the computer’s hardware. Hardware consists of devices listed below:'''

• Input devices to enter the information such as the keyboard, mouse, microphone or scanner.

• The Central Processing Unit (CPU), containing the Arithmetic Logic Unit (ALU) which carries out the arithmetic and logical computations and the control unit which executes commands typed at the keyboard or stored in program.

• Storage is split into short-term memory, using microchips inside the computer which hold data and programs while processing is being carried out and long-term storage, normally using magnetic disks.

• Output devices for communicating the results of the processing such as printer, monitor or loudspeaker. `

• The circuitry linking these various devices, consisting of 8, 16, 32 or 64 strands of parallel wires, called buses, along which all the bits that make up each item of the information travel in parallel.

'''Software, in contrast, consists of computer programs. A computer program is a set of instructions to solve a particular problem. Programs can be stored on magnetic disks, magnetic tapes and other media but the essence of software is the set of instructions that makes up the programs, not the physical media on which they are recorded.'''

'''An intermediate form between hardware and software is firmware, which consists of software embedded in electronic devices during their manufacture. Firmware is used when the programs are rarely or never expected to be changed, for example in toys or appliances. Firmware is also used when the programs must not be lost when the power is off.'''

'''Any operation performed by software can also be built directly into the hardware and any instruction executed by the hardware can also be simulated in software. Hardware and software are logically equivalent. The decision to put certain functions in hardware and others in software is based on such factors as cost, speed, reliability and frequency of expected changes. There are no hard and fast rules about what must be in hardware and what must be in software. Designers with different goals may make different decisions.'''

COMPUTER SOFTWARE Computer software can be split into two categories, that is, system software and application software

• System Software '''The system software of a computer consists of a collection of operative programs whose purpose is to make the use of the computer more effective. The customer who buys a computer would usually receive, in addition to the hardware, any available software needed for the effective operation of his computer. A computer without some kind of system software would be very ineffective and most likely impossible to operate.'''

'''The production of system programs is a complex task requiring extensive knowledge and specialized training in computer science. System programs offer several advantages and conveniences to application programmers and computer users in general.'''

• Application Software

This is the software that enables us to do the things that we bought our computer for, such as typing a letter, preparing payroll, playing games, writing music or creating animated displays.

Application software is normally supplied as a package, consisting of the following:

• The software, supplied on floppy disk of CD ROM.

• A manual, explaining how to use the software.

• Training material, either supplied on disk, CD ROM or in a booklet.

'''IBM PCs and compatibles are supported by thousands of software packages. Most of these are reasonably priced. The Apple Macintosh is also well supported by application software, though not to the same extent as the IBM PC.'''

The kinds of application packages that available include the following:

Record-keeping software Spreadsheet software Word processing and desktop publishing software Business graphics and presentation software Communication software Diary systems and other personal productivity tools Drawing and computer-aided design software Games Music synthesis Painting and animation software Medical Software

'''Some packages can perform more than one of these. For example, there are a number of office administration packages such as Office 2000 of Microsoft that will carry out word processing, record-keeping, spreadsheet work and business graphics. These are called integrated packages because they integrate or bring together these varied tasks.'''

INPUT AND OUTPUT DEVICES '''Before a computer can gat to work solving a problem, it must be given the program and the data if there is any. After it has found the solution, the computer must communicate this solution to the human beings who posed the problem in the first place. The topic of getting information into and out of computers is called input/output or usually just I/O.'''

'''Input/output devices are used for communication with the computers. Hundreds of kinds of I/O devices are available today and the number is growing rapidly. A few of the more common ones are listed below:'''

Cathode Ray (CRT) monitors Keyboards Printers Scanners Pen and ink plotters that draw graphs Computer mouse Microphones Speakers Electric light pen

•	I/O PROCESSORS '''Some I/O devices can transmit a large amount of data in a short time. If the CPU had to process every character separately, much CPU time would be wasted. To avoid tying up the CPU for long periods of time on I/O, must of the computers have one or more specializes, low-cost I/O processors. Because the I/O is performed by these special processors, the CPU is available to spend most of its time on more difficult computations. The I/O processors can run in parallel with the CPU. In other words, while the CPU is busy in computing, the I/O processors can be doing I/O.'''

•	INPUT DEVICES '''A variety of input devices exist to convert information in any form (data, text, voice or image) into binary pulses recognized by computers. Some of these devices are described below:'''

Keyboard

'''The keyboard is still the primary device for inputting information to a computer, though voice input devices may ultimately supersede it. It operates by converting key presses to electronic signals in binary digital form. The typical computer keyboard has the standard character keys found on a typewriter together with a number of special keys described below:'''

•	Function keys, up to 12 in number, positioned above the character keys, which can be programmed by the user or by the software being run, so that a single key depression sends a command or string of commands to the computer.

•	The CTRL and ALT keys (short for Control and Alternate), which are always used in conjunction with other keys to issue commands to the computer.

•	The four arrow keys, which move the cursor one character position in the cursor on the screen.

•	The Page Up and Page Down keys, which are normally programmed to move the cursor one page up or down.

•	The home key, which may be programmed to move the cursor to the left of the screen or the beginning of the document.

•	The End key, which may be programmed to move the cursor to the right of the screen or the end of the document.

•	The Esc key, which is often programmed to enable you to escape form your currently selected option or task.