It Notes Updated33

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Course Contents (Theory)

Introduction to Computers Classification of Digital Computer Systems. Anatomy of Digital Computers (Function and

components of Computer) Memory Units (RAM, ROM etc) Input Devices Output Devices Storage Devices (CD ROM etc)

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Course Contents(Theory)

Introduction to Computer Software Introduction to Computer Networks Introduction to Telecommunication What is Electronic Mail. Computer Used in Home Computer Used in Entertainment, Science, Media

etc History of Computing.

Intro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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Course Contents(Theory)

Introduction of C Language Introduction of www (World Wide Web)


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Course Contents (Practical)

Introduction of Microsoft Word Introduction of Microsoft Power Point Introduction of Microsoft Excel Introduction of Outlook Express


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Subject Details

This Subject is of 4 Credit Hours 3 Credit Hours of Theory 1 Credit hour for Practical 1 Extra hour for Practical.


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Division of Marks

Total 100 Marks Subject 8 Quizzes (10 %) 4 Assignments ( 10%) Midterm (20 Marks) Final Practical (20%) End Term (40%)


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Practical 1

Make a document of two Pages and do the following action on the document:

a) File Menus commands

b) Edit Commands

c) View Commands


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Introduction To Computers


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What Is ComputerA computer is a programmable machine. The two principal characteristics of computer are: -

It responds to a specific set of instructions in a well defined manner. It can execute a pre-recorded list of instructions (a program).

Modern computers are electronics and digital. The actual machinery wires, transistors, and circuits is called hardware The instructions and data are called software. Intro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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Hardware Components of Computer

Central Processing Unit (CPU). The “heart” of the computer, the component that actually executes instructions.

Memory enables a computer to store, at least temporarily, data and programs.

Input Device. Usually a keyboard or mouse, the input device is the conduit through which data and instructions enter a computer.


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Output Device. A display screen, printer, or other such devices that lets you see what the computer has

accomplished.

Mass Storage Device. Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.


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TYPES OF COMPUTERS

Computers can be classified by their size and power as follows:-

Personal Computer. A small, single user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.

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


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Minicomputer. A multi user computer capable of supporting 10 to hundreds of users simultaneously.

Mainframe. A powerful multi user computer capable of supporting many hundreds of users simultaneously.

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


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Characteristics Of Computer

Word Length Speed Storage Accuracy Versatility Automation Diligence


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Word Length

A digital computer operates on binary digits 0 and 1.A binary digit is called a bit. A group of 8 bits is called a byte. The number of bits that a computer can process at a time in parallel is called its word length. Commonly used work lengths are 8, 16, 32 or 64 bits. Word length is the measure of the computer power of a computer. The longer the work length, the more powerful the computer is.


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Speed

Computer can calculate at very high speeds. A microcomputer, for example, can execute millions of instructions per second over and over again without any mistake. As the power of the computer increases, the speed also increases. For example, supercomputers can operate at speeds measured in nanoseconds and even in picoseconds.


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Storage

Computers have their main memory and auxiliary memory systems. A computer can store a large amount of data.

The factor that makes computer storage unique is not that it can store vast amount of data, but the fact that it can retrieve the information that the user wants in a few seconds. For example, computer dictionaries are available and the contents of these software versions are the same as that of the printed dictionary. But you can search and find the meaning of a word from the computer version in a matter of seconds, whereas with the traditional dictionary, you have to turn the pages until you get the correct work. So the capability of storing and retrieving huge amounts of data in a fast and efficient manner is one of the important characteristics of computers.


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Accuracy

The accuracy of a computer system is very high.

Errors in hardware can occur, but error detecting and correcting

techniques will prevent false results.

In most cases, the errors are due to the human factor rather than the

technological flaws.

For example, if a program is wrongly coded, if the data is corrupted, or if

the program logic is flawed, then irrespective on which computer you run

it, you will always get wrong results.

Another area where mistakes can creep in is during data entry.


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Versatility

Computers are very versatile machines.

They are capable of performing almost any task, provided the task can be reduced

to a service of logical steps.

Computers can communicate with computers and can receive and send data in

various forms like text, sound, video, graphics, etc.

Sounds for example in MP3 format.(a.mp3,a.wma)

Video for example in wmv format.(a.wmv)

Graphic for example in JPG,GIF,BMP formats.(a.jpeg,a.gif,a.bmp)

The ability of computer to communicate to one another has led to the development

of computer networks, Internet, WWW and so on.

Today, we can send e-mail to people all around the world. We now live in a

connected world and all this is possible because of computers and other related

technologies.


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AutomationThe level of automation achieved in a computer is phenomenal. It is not a

simple calculator where you have to punch in the numbers and press the

equal to sign to get the result.

Once a task is initiated, computers can proceed on its own till its

completion.

Computers can be programmed to perform a series of complex tasks

involving multiple programs.

Computers will perform these things flawlessly. They will execute the

programs in the correct sequence, they will switch on / off the machines at

the appropriate time, they will monitor the operational parameters, they will

send warning signals or take corrective actions if the parameters exceed

the control level, and son on.


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Diligence

Diligence means being constant and earnest in effort and application.

Human beings suffer from weakness like tiredness, lack of concentration, etc.

Humans have feelings, they become sad, depressed, bored, and negligent and it

will reflect on the work they do. Moreover, human beings cannot perform the same

or similar tasks over again with the same precision, accuracy and enthusiasm as the

first time. After some time, people will become bored and tedium will set in. This

will affect the performance.

Being a machine, a computer does not have any of these human weaknesses.

They won’t get tired or board. They will not go into depression or loose

concentration. They will perform the tasks that are given to them, irrespective of

whether it is interesting, creative, monotonous or boring, irrespective of whether it is

the first time or the millionth time, with exactly the same accuracy and speed.


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What Computer Can Do?

Computers In Business

In Business Computers are in the Super Markets, Banks like ATM Machines etc.

Computers In Science

Scientists and researchers use computers to develop theories, to collect and test data, to simulate test environments, and to exchange information electronically with colleagues around the world. Researchers can access databases in distant

locations from their desktop.


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Computers In Media

Musicians and signers have teamed up with computers to create an amazing range of instruments and sounds simply by playing a keyboard. The musical instruments digital interface (MIDI) is a system that synchronizes hardware and software that produces electronic tones. The music concerts and movies all use computers for a variety of purpose ranging from producing astonishing special effects and computer animations to control stage lighting.

Computers In Home

We use Computers in home for entertainment and work purposes


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What Computer Cant Do?

Productivity

Reasoning

Errors


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Productivity

�Computers haven’t yet met all our expectations as a

productivity improvement tool.

�Sometimes it takes longer to do things with a computer than it

would to do them manually.


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Reasoning

Thus, it seems fair to say that in the same way we have built machines to replace human labour, we have also sought to build machines that to certain kind of thinking for us. But computers still lack many of the mental capabilities possessed by five-year children. Simply put, computer can’t think. They can’t discriminate or assibilate widely divergent kinds of data, and they have absolutely no capacity for ethical evaluation. These are still powers possessed only be people, and it may be wise to keep things that way.


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Errors

Computers don’t make errors, people do – either in the way they program computers or in the way they use them. However, computers are extremely finicky machines and often frustratingly literal. This is because they use the principle or logic, for example, 1 must always be equal to 1. It you type “one”, the computer wouldn’t understand it. Every instruction must be precisely entered. The computer does not allow spelling mistakes or typos.


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Abbreviations Used In the Previous Chapter

MP3(MPEG Audio Layer 3 MPEG(Moving Picture Expert Group) WMA(Window Media Audio File) WMV(Window Media Video File) JPEG(Joint Photographic Expert Group) GIF(Graphic Interchange Format) BMP(Bitmap)

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Chapter 2 (Types Of Computers)

Microcomputers Minicomputers Main Frame Computers Super Computers


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Microcomputers

PC’s Workstation Portable Computers

a) Laptops or Notebooks

b) Sub Notebooks

c) PDA’s


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Personal Computers (PCs)

Until recently, PCs were desktop or portable machines. These machine ran comparatively easy-to-use application software such as a word processor, spreadsheets, etc. They were usually easier to use and more affordable than workstations. However, they had less sophisticated video display screens, operating systems and network capabilities. Most important, they did not have the processing power that workstations did. Examples of personal computers are Acer’s Aspire, Compaq Presario, etc.


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Workstations Workstations are, again, until recently, expensive, powerful machines used by engineers,

scientist, and other professional who processed a lot of data. People who need to run complex programs and display both works in progress and result graphically also use workstations. Workstations use sophisticated display screens featuring high-resolution colour graphics and operating systems such as UNIX that permitted multitasking. Workstations also use powerful networking links to other computers. The most significant distinguishing factor, however, is the powerful processor, which could churn out results much faster than the PCs. The more powerful workstations are called Super micros. Examples of well known workstations are those made by Sun, Apollo, Hewlett-Packard, NEXT, and IBM.

However, the distinction between PCs and workstations is now blurring. The principal reason is that microprocessors used in PCs are now powerful as many of those used in workstations. More powerful microprocessors and increased graphics and communications capabilities now let end users run software that previously run only on more powerful machines.


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Portable Computers Personal computing market is seeing the miniaturization phenomena. Now, computers are becoming smaller yet more powerful. One type of PC that is rapidly growing in popularity is the portable computer, which can be easily carried around. There are three categories of portable computers: Laptops or Notebook PCs, Subnotebooks and Personal Digital Assistants.

Laptops /Notebooks Laptops may either be AC powered, battery- powered, or both. These computers are ideal for users who work away from their offices.The users of these computers might be an executive on the move, a student, a journalist, a salesperson, etc. These computers combine the power of the PC with mobility. An example is IBM ThinkPad.


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Subnotebook Subnotebook are for frequent flyers and life on the roadprofessionals. Subnotebook users give up a full display screen and Keyboard in exchange for less weight. These computers fit easily into any briefcase. They typically have an external floppy disk drive and monochrome monitor, although of late colour models are available. An example of a colour Subnotebook is Toshiba Protégé.

Personal Digital Assistants (PDAs) PDAs are much smaller than the Subnotebooks, they combine pen input, writing recognition, personal organizational tools, and communicational capabilities in a very small package Typical users are executives, businessmen, etc. Who use these machines for their day to day activities scheduling, organization, etc.


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Minicomputers, also known as mid range computers were first developed as special- purpose mainframe computers. They were used, for instance, to control machines in a manufacturing unit. However, now they are widely used as general-purpose computers. Thus the line between minis and mainframes has blurred and is constantly changing. Indeed, the more powerful minicomputer models are called superminis. Also, the increasing power of microcomputer workstations have made it harder to distinguish between minis and microcomputers. One of the popular minicomputer systems is the VAX made by Digital Equipment Corporation.Minicomputers work well in what are known as Distributed Data Processing (DDP). That is, a company’s processing power us decentralized, or distributed across different computers.An example of such a computer architecture is the Client/Server model, in which end users can process at their own microcomputers. End users can also access and share the resources of the server, which usually is a minicomputer. For example, an executive could use the server to search the company’s centralized database and retrieve selected data. He/she could then use a spreadsheet on his/her microcomputer to analyze the data.

MINICOMPUTERS


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MINICOMPUTER(FIGURE)


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Mainframe computers can process several million-program instructions per second. Large organizations rely on these room-size systems to handle large programs with lots of data.

Mainframes are mainly used by insurance companies, banks, airline and railway reservation systems, etc. An advanced mainframe made by IBM is S/390.

MAINFRAMES


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MAINFRAME(Figure)


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SUPERCOMPUTERS

Supercomputers are the fastest calculating devices ever invented. A desktop microcomputer processes data and instruction in millionths of a second, or, microseconds. A supercomputer, by contrast, can operate at speeds measured in nanoseconds and even in picoseconds – one thousand to one million times as fast as microcomputers.Most supercomputers are used by government agencies. These machines are for applications requiring very large programs and huge amounts of data and must be processed quickly. Examples of such task are weather forecasting, oil exploration, weapons research, and large-scale simulation. The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently.


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Chapter Number 3FUNCTION AND COMPONENTS OF A COMPUTER

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Functions of a Computer

A computer does mainly the following four functions: -

Receive input – Accept information from outside through various input devise like the keyboard, mouse, etc.

Process information – Perform arithmetic or logical operations on the information.

Produce output – Communicate information to the outside world through output devices like monitor, printer etc.

Store information – Store the information in storage devices like hard disk, floppy disks, etc.


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Components of a Computer

CENTRAL PROCESSING UNIT (CPU)The part of the computer that executes program instructions is

known as the processor or central processing unit (CPU). In a microcomputer, the CPU is on a single electronic component, the microprocessor ship, written the system unit or system cabinet. The system unit also includes circuit boards, memory chips, ports and other components. A microcomputer’s system cabinet will also house disk drives, hard disks, etc, but these are considered separate from the CPU.

The CPU has two parts – the control unit and the arithmetic-logic unit (ALU). In a microcomputer, both are on the microprocessor chip.


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Control unit

The control unit tells the rest of the computer system how to carry out a program’s instructions. It directs the movement of electronics signals between memory – which temporarily hold data, instructions and processed information – and the ALU. It also directs these control signals between the CPU and input / output devices.

Arithmetic-Logic Unit (ALU)

Arithmetic-Logic Unit, usually called the ALU, performs two types of operations – arithmetic and logical. Arithmetic operations are the fundamental mathematical operations consisting of addition, subtraction, multiplication and division. Logical operations consist of comparisons. That is, two pieces of data are compared to see whether one is equal to, less then, or greater than the other.


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MEMORY

Memory – also known as the primary storage or main memory – is a part of the microcomputer that holds data for processing, instructions for processing the data (the program) and information (processed data).

Parts of the contents of the memory are held only temporarily, that is, it is stored only as long as the microcomputer is turned on. When you turn the machine off, the contents are lost. The capacity of the memory to hold data and program instructions varies in difference computers. The original IBM PC could hold approximately 6,40,000 characters of data or instructions only. But modern microcomputers can hold million, even billions of characters in there memory.


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RegistersComputers also have several additional storage locations called

registers. These appear in the control unit and ALU and make processing more efficient. Registers are sort of special hi-speed staging areas that hold data and instructions temporarily during processing. They are parts of the control unit and ALU rather than the memory. Their contents can therefore be handled much faster than the contents of the memory.

AddressesTo locate the characters of data or instructions in the main

memory, the computer stores them in locations known as addresses. A unique number designates each address. Addresses can be compared to post office mailboxes. Their numbers stay the same, but contents continuously change.


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HOW THE CPU AND MEMORY WORKThe working of the CPU and memory is shown in figure 3.2. The various steps involved for multiplying two numbers is shown in the figure and explained below.

The control unit recognizes that the program has been loaded into memory. It begins to execute the first step in the program.

The program tells the user, “Enter 1st Number”.

The user types the number 10 on the keyboard. An electronic signal is sent to the CPU.

The control unit recognizes this signal and routes the signal to an address in memory – adress7.

After completing the above instructions, the next instruction tells users, “Enter 2nd Number”.

The user types the number 4 on the keyboard. An electronic signal is sent to the CPU.


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The control unit recognizes this signal and routes it to memory address 8.

The next program instruction is executed – “Multiply 1st and 2nd Numbers”.

To execute this instruction, the control unit informs the ALU that two numbers are coming and the ALU is to multiply them. The control unit next sends to the ALU a copy of the contents of address 7 (10) and address 8 (4).

ALU performs the multiplication: 10 x 4 = 40

The control unit send a copy of the multiplied result (40) back to memory, to address 9.


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The next program instruction is executed: “Print the Result”.

To execute this instruction, the control unit sends the contents of the address 9 (40) to the monitor.

Monitor displays the value 40.

Final instruction is executed: “End”. The program is complete.: “End”. The program is complete.


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MEMORY


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Memory units are the internal storage areas in a computer. The Term ‘Memory’ identifies data storage that comes in the form of chips, and the word ‘Storage’ is used for memory that exists on the tapes or disks.

Every computer comes with a certain amount of physical memory , usually referred to as the main memory or the RAM. You can think of the main memory as an array of boxes , each of which can hold a single byte of information .A computer that has 1 Megabyte of memory, thus , can hold about 1 million bytes of information.

What is Memory


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Types of memory

RAM (Random Access Memory) ROM (Read Only Memory) PROM (Programmable Read only Memory) EPROM (Erasable Programmable Read Only Memory) EEPROM (Electrically Erasable Programmable Read Only

Memory)


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RAMThis is the same as the main memory. When used by itself, the term RAM refers to read and write memory; that is , you can both write data into the RAM and read data from RAM. This is in contrast to ROM, which permits you only to read data. Most RAM are volatile, which means that it requires a steady flow of electricity to maintain its contents. As soon as the power is turned off, what ever data was in RAM is lost.

RAM is the most common type of memory found in computers and other devices, such as printers.


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Two basic types of RAMDynamic RAMStatic RAM

Dynamic RAM Dynamic RAM needs to be

refreshed thousands of times

per second. Not much Expensive Volatile

Static RAM It needs to be refreshed less

often More Expensive Volatile


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ROMIt is a computer memory on which data has been prerecorded. Once data has been written on to a ROM chip, it cannot be removed and can only be read. Unlike the main memory RAM), ROM retains its contents even when the computer is turned off.ROM is referred to as being nonvolatile, whereas RAM is volatile.Most personal computers contain a small amount of ROM that stores critical programs such as the programs that boots the computer. In additions , ROMS are used extensively such as the program that boots the computer. In addition ROMS are used extensively in calculators and peripheral devices such as laser printers, which fonts are often stored in ROMS. A variation of a ROM is the PROM.PROMS are manufactured as blank chips on which data can be written.


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PROM

A PROM is the memory chip on which data can be written only once. Once a program has been written onto a PROM, it remains there forever. Unlike the main memory , PROMs retain their contents when the computer is turned off.

The difference between a PROM and a ROM is that a PROM is manufactured as blank memory, where as a ROM is programmed during the manufacturing process. To write data onto a PROM chip, you need a special device called a PROM programmer or a PROM burner. The process of programming a PROM is sometimes called burning the PROM.


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EPROMEPROM is a special type of memory that retains its contents until it is exposed to ultraviolet light. The ultra violet clears its contents, making it possible to reprogram the memory.

An EPROM differs from a PROM is that a PROM can be written to only once and cannot be erased. EPROMs are used widely in personal computers because they enable the manufacturer to change the contents of the PROM before the computer is actually shipped. This means that bugs can be removed and new versions installed shortly before delivery.


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EEPROMAn EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge. Like other types of PROM . EEPROM retains its contents even when the power is turned off.Also like all other types of ROM, EEPROM is not as fast as RAM.

EEPROM is similar to flash memory. The principal difference is that EEPROM requires data to be written or erased one byte at a time where as flash memory allows data to be written or erased in blocks. This makes flash memory faster.


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Flash Memory

Flash memory is a special type of EEPROM that can be erased and reprogrammed in blocks instead of one byte at a time. Many modern PCs have their BIOS Basic Input Output System) stored on a flash memory chip so that it can easily be updated if necessary. Such a BIOs is sometimes called a flash BIOs.Flash memory is also popular in moderns because it enables manufacturer to support new protocol as they become standardized.


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Chapter No 5Auxiliary Storage


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INTRODUCTION

Auxiliary storage also known as auxiliary memory or secondary storage is the memory that supplements the main storage. This is a long term, non volatile memory. The term non volatile means it stores and retains the programs and data even after the computer is switched off.


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Auxiliary storage devices are also useful in transferring data or programs from one computer to another.

They also function as back up devices which allows to backup the valuable information that you are working on

So even if by some accident your computer crashes and the data in it is unrecoverable, you can restore it form your back-ups.

The most common types of auxiliary storage devices are magnetic tapes, magnetic disks, floppy disks, hard disks, etc.


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There are two types of auxiliary storage devices. This classification is based on the type of data access: sequential and random.

Based on the type of access they are called sequential access media and random media

In the case of sequential access media, the data stored in the media can only be read in sequence and to get to a particular point on the media you have to go through all the preceding points.

Magnetic types are examples of sequential access media.


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In contrast, disks are random access also called direct access media because a disk drive can access any point at random without passing through intervening points

Other examples of direct access media are magnetic disks, optical disks, zip disks, etc.


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MAGNETIC TAPE

Magnetic tape is a magnetically coated strip of plastic on which data can be encoded.

Tapes for computer are similar to the tapes used to store music Some personal computers, in fact, enable you to use normal cassette

tapes.

Storing data on tapes is considerably cheaper than storing data on disks. Tapes also have large storage capacities, ranging from a few hundred kilobytes to several gigabytes.


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Accessing data on tape, however, is much slower than accessing data on disks.

Tapes are sequential access media which means that to get to a particular point on the tape, the tape must go through all the preceding points.

In contrast, disks are random access media because a disk driver can access any point at random without passing through intervening points.


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Because tapes are so slow, they are generally used only for long term storage and backup.

Data to be used regularly is almost always kept on a disk.

Types come in a variety of sizes and formats.

Tapes are sometimes called streamers or streaming tapes.


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Types of Magnetic Tapes

Helical-scan Cartridge

DAT Cartridge


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Helical-scan Cartridge

A type of magnetic tape that uses the same technology, as VCR tapes.

The term helical scan usually refers to 8mm tapes, although 4mm tapes (called DAT tapes) uses the same technology.

The 8mm helical scan tapes have data capacities from 2.5 GB to 5 GB.


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DAT Cartridge

A DAT cartridge is slightly larger than a credit card and contains a magnetic tape that can hold from 2 to 24 gigabytes of data.

It can support data transfer rates of about 2 MBps (Million Bytes per second).

Like other types of tapes, DATs are sequential access media. The most common format for DAT cartridges is DDS (digital data storage) which is the industry standard for digital audio tape (DAT) formats.

The latest format, DDS-3 specifies tapes that can hold 24 GB (the equivalent of over 40 CD-ROMS) and support data transfer rates of 2 MBps.


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Magnetic Tape Picture


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WINCHESTER DISK

The term Winchester comes for an early type of disk drive developed by IBM that stored 30 MB and had a 30 millisecond access time; so its inventors named it a Winchester in honour of the 30 calibre rifle of the same name.

Although modern disk drives are faster and hold more data, the

basic technology is the same, so Winchester has become synonymous with hard disk.


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Winchester Disk Picture


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HARD DISK

Hard disk is a magnetic disk on which you can store computer data. The term hard is used to distinguish it form a soft, or floppy disk

Hard disks hold more data and are faster than floppy disks. A

hard disk, for example, can store anywhere from 10 megabytes to several gigabytes, whereas most floppies have a maximum storage capacity of 1.4 megabytes.

There are two types of removable hard disks: disk packs and removable cartridges.


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Hard Disk Picture


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FLOPPY DISK

Floppy disk is a soft magnetic disk. It is called floppy because it flops if you wave it fat least, the 5¼ inch variety does).

Unlike most hard disks, floppy disks (often called floppies or diskettes) are portable, because you can remove them from a disk drive.

Disk drives for floppy disks are called floppy drives. Floppy disks are slower to access than hard disks and have less

storage capacity, but they are less expensive and are portable .


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5¼ inch. The common size for PCs made before 1987. This types of floppy is generally capable of storing between 100 K and 1.2 MB (megabytes) of data. The most common sizes are 360 K and 1.2 MB.

3½ inch. Floppy is something of a misnomer for these disks, as they are encased in a rigid envelope. Despite their small size, microfloppies have a larger storage capacity than their cousins – form 400K to 1.4 MB of data. The most common sizes for PCs are 720 K (double-density) and 1.44MB (high-density). Macintoshes support disks of 400K, 800K and 1.2MB.


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Floppy Disk Picture


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Floppy Drive Picture


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ZIP DISK

These are high capacity floppy disk drives developed by the Iomega Corporation. \

Zip disks are slightly larger than the conventional floppy disks, and are about twice as thick. They can hold 100 MB of data.

Because relatively inexpensive and durable, they have become a popular medical for backing up hard disks and for transporting large files.


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Zip Disk Picture


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JAZ DISK

These are removable disk drives developed by the Iomega Corporation.

The Jaz drive has a 12mm average seek time and a transfer rate of 5.5Mbps.

The removable cartridges hold 1GB of data. The fast data rates and large storage capacity make it a viable alternative for backup storage as well as everyday use.


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Jazz Disk Picture


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OPTICAL DISK

Optical Disks are a storage medium from which data is read and to which it is written by laser.

Optical disks can store much more data – up to 6 gigabytes (6 billion bytes) – than magnetic media, such as floppies and hard disks.

There are three basic types of optical disks:

CD-ROM. Like audio CDs, CD ROMs come with data already encoded onto them. The data is permanent and can be read any number of times, CD ROMs cannot be modified.


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WORM. This term stands for write once, read many. With a WORM disk drive, you can write data onto a WORM disk, but only once. After that, the WORM disk behaves like a CD ROM.

Erasable – Optical disks that can be erased and loaded with new data, just like magnetic disks. These are often referred to as EO (erasable optical) disks.


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CD ROM

CD ROM, which is pronounced as ‘see-dee-rom’, is the abbreviation of Compact Disk-Read-Only Memory.

CD ROM is a type of optical disk capable of storing large amounts of data – upto 1 GB, although the most common size is 630 MB (megabytes).

A single CD ROM has the storage capacity of 700 floppy disks, enough memory to store about 300,000 text pages.


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CD ROMs are recorded by the vendor, and once recorded; they cannot be erased and filled with new data.

To read a CD, you need a CD ROM player. Also called a CD ROM drive, a CD ROM player is a drive that can read information from a CD ROM.

CD ROM players can be either internal in which they fit in a bay, or external, in which case they generally connect to the computer’s parallel port.


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Parallel CD ROM players are easier to install but they have several disadvantages.

They’re somewhat more expensive than internal players they use up the parallel port which means the you can’t use that port for another device such a printer, and the parallel port itself may not fast enough to handle all the data pouring through it.


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There are a number of features that distinguish CD ROM players, the most important of which is probably their speed.

CD-ROM players are generally classified as single speed or some multiple of single speed. For Example, a 4X player access data at four times the speed of a single speed player.

Also you need to be aware whether the CD ROM uses CLV(Constant Linear Velocity) or CAV(Constant Angular Velocity) technology.


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There are a number of features that distinguish CD ROM players, the most important of which is probably their speed.

CD-ROM players are generally classified as single speed or some multiple of single speed. For Example, a 4X player access data at four times the speed of a single speed player.

Also you need to be aware whether the CD ROM uses CLV(Constant Linear Velocity) or CAV(Constant Angular Velocity) technology.


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The reported speeds of players that use CAV are generally not accurate because they refer only to the access speed for outer tracks. Inner tracks are accessed more slowly.

Two more precise measurements are the Drive Seek time and transfer rate.

The seek time, also called access time, measures how long, on average, it takes the drive to access a particular peace of information.


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The data transfer rate measures how much data can be read and sent to the computer in a second.

Aside from its speed, another important feature of a CD ROM player is its compatibility with existing standards.

If you plan to run CD ROMs in a Windows environment, you need a player that conforms to the MPC III standard.

If you want to be able view photographs stored on CD ROM, make sure your player conforms to Kodak’s Player CD format.


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Connectivity of CD ROM

Almost all CD ROMs conform to a standard size and format, so it is usually possible to load any type of CD into any ROM player. In addition, most CD ROM players are capable of playing audio CDs, which share the same technology.


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CD ROMs are particularly well suited to information that requires large storage capacity. This includes colour graphics, sound, and especially video. In recent years, as the prices of CD ROM players have decreased, and the tools for creating new CD ROM titles have improved, the CD ROM industry has been expanding rapidly. To date, the most popular CD ROM titles have been computer games and multimedia reference works.


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CD-ROM Drive Picture


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CD-R Drive

CD-R drive, which is short for Compact Disk-Recordable drive, is a type disk drive that can create CD ROMs and audio CDs.

This allows the users to “master” a CD ROM or audio CD for publishing. Until recently, CD_R drives were quite expensive, but prices have dropped dramatically.

To create CD-ROMs and audio CDs, you’ll need not only a CD-R drive, but a CD-R software package.


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Often, it is the software package, not the drive itself that determines how easy or difficult it is to create CD-ROMs. CD-R drives can also read CD ROMs and play audio CDs.


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CD-R Drive Picture


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CD-RW Disks

CD-RW disk is short for CD-Rewritable disk and this is a new type of CD disk that enables you to write onto it in multimedia sessions.

One of the problems with CD-R disks is that you can only write to them once.

With CD-RW drives and disks, you can treat the optical disk just like a floppy or hard disk, writing data onto it multiple times.


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The first CD-RW drives became available in mid 1997. The can read CD-ROMS and write onto today’s CD-R disks, but they cannot a popular storage medium.


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CD-RW Drive Picture


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MAGNETO-OPTICAL (MO) DRIVES

This is a type of disk drive that combines magnetic disk technologies with CD-ROM technologies.

Like magnetic disks, MO disks can be read and written to

And like floppy disks, they are also removable.


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However, their storage capacity can be more than 200 megabytes, much greater than magnetic floppies

In terms of data access speed, they are faster than floppies and CD-ROMs but not as fast as hard disk drives.


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Chapter Number 6Numbers System


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Binary to Decimal Conversion

Example 1011 Decimal Conversion 1*2^3+0*2^2+1*2^1+1*2^0 8 + 0 + 2 + 1

11


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Decimal to Binary

8

128 64 32 16 8 4 2 1 0 0 0 0 1 0 0 0


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Hex to Binary

0ABC H (Hex) 0=0000 A=1010 B=1011 C=1100 0000 1010 1011 1100 (Binary) 0000=1 Nibble 1010=1 Nibble and so on


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Binary to Hex

Binary TO Hex Example

0000111100001111(Binary)

0 F 0 F (Hex)


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Hex to Decimal

Example

0AFB2H (Hex)

0*16^4+A*16^3+F*16^2+B*16^1+2*16^0

40960 + 3840 +176 + 2 =44978


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Decimal to Hex Decimal =44978

Division Quotient Remainder Hex Number

44978/16 2811 2 2

2811/16 175 11 B

175/16 10 15 F

10/16 0 10 A

Hex - 0AFB2


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CHAPTER NUMBER 7 INPUT DEVICE


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Input Device

An input device is any machine that feeds data into a computer. For example, a keyboard is an input device, whereas a display monitor is an output device.

Input devices other than the keyboard are sometimes called alternate input devices. Mice, trackballs, and light pens are all alternate input devices.


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KEYBOARD

Keyboard is an input device consisting of a set of typewriter –like keys that enable you to enter data into a computer.

Computer keyboards are similar to electric-typewriter keyboards but contain additional keys.

The keys on computer keyboards are often classified as follows:

-


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Alphanumeric keys – letters and numbers

Punctuation Keys – Comma, period, semicolon, and sp on.

Special keys – Function keys, control keys, arrow keys, Caps Lock Key and so on.


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The standard layout of letters, numbers and punctuation is know as a QWERTY keyboard because the first five keys on the top row of letters spell QWERTY. The QWERTY keyboard was designed in the 1800s for mechanical typewriters and was actually designed to slow typists down to avoid jamming the keys. Another keyboard design, which has letters positioned for speed typing, is the Dvorak keyboard.


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There are actually three different PC keyboards the original PC keyboard, with 84 keys, the AT keyboard, also with 84 keys and the enhanced keyboard, with 101 keys. The three differ somewhat in the placement of function keys, the Control key, the Return key and the shift key.


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In addition to these keys, IBM keyboards contain the following keys: Page UP, Page Down, Home, End, Insert, Pause, Num Lock, Scroll Loc R, Break, Caps Lock, Print Screen. Many companies have developed ergonomic keyboards, which reduce the strain while typing with the aim to prevent stress related injuries. Microsoft’s natural keyboard is one example.


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There are several different types of keyboards for the Apple Macintosh. All of them are called ADB keyboards because they connect to the Apple Desktop bus (ADB). The two main varieties of Macintosh keyboards are the standard keyboard and the extended keyboard, which have 15 additional special-function keys.


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MOUSE

Mouse is a device that controls the movement of the cursor or pointer on a display screen.

A mouse is a small object you can roll along a hard, flat surface. Its name is derived from its shape, which looks a bit like a mouse, its

connecting wire that one can imagine to be the mouse’s tail, and the fact that one must make it scurry along a surface.

As you move the mouse, the pointer on the display screen moves in the same direction.

Mice contain at least one button and sometimes as many as three, as which have different functions depending on what program is running.


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Invented by Douglas Engelbard of Stanford Research Center in 1963, and pioneered by Xerox in the 1970s, the mouse is one of the great breakthroughs in computer ergonomics because it frees the user to a large extent from using the keyboard.

In particular, the mouse is important for graphical user interfaces because you can simply point to options and objects and click a mouse button. Such applications are often called point and click and click programs. The mouse is also useful for graphics programs that allow you to draw pictures by using the mouse like a pen, pencil, or paintbrush.


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Types of Mice Mechanical has a rubber or metal ball on its

underside that can roll in all directions. Mechanical sensors within the mouse detect the direction the ball is rolling and move the screen pointer accordingly.

Optomechanical Same as a mechanical mouse, but uses optical sensors to detect motion of the ball.

Optical Uses a laser to detect the mouse’s movement you must move the mouse along a special mat with a grid so that the optical mechanism has a frame of reference. Optical mice have no mechanical moving parts. They respond more quickly and precisely than mechanical and optomechanical mice, but they are also more expensive.


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Connections

Mice connect to PCs in one of threeways. Serial mice connect directly to an RS-232C serial

port or a PS/2 port. This is the simplest type of connection.

USB Mouse Cordless mice aren’t physically connected at all.

Instead they rely on infrared or radio waves to communicate with the computer


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Mousepad

Mouse pad is a pad over which you can move a mouse. Mouse pads provide more traction than smooth surfaces such as glass and wood so they make it easier to move a mouse accurately. For mechanical mice, mousepads are optional. Optical mice, however, require special mousepads that have grids drawn on them.


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TRACKBALL

Trackball is another pointing device. Essentially, a trackball is a mouse lying on its back. To move the pointer, you rotate the ball with your thumb, your fingers, or the palm of your hand. There are usually one to three buttons next to the ball, which you use just like mouse buttons.

The advantage of trackballs over mice is that the trackball is stationary so it does not require much space to use it. In addition, you can place a trackball on any type of surface, including your lap. For both these reasons, trackballs are popular pointing devices for portable computers.


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Track Ball Picture


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JOYSTICK

A lever that moves in all directions and controls the movement of a pointer or some other display symbols. A Joystick is similar to a mouse, except that with a mouse the cursor stops moving as soon as you stop moving the mouse.

With a joystick, the pointer continues moving in the direction the joystick is pointing. To stop the pointer, you must return the joystick to its upright position. Most joysticks include two buttons called triggers.

Joysticks are used mostly for computer games


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Joy Stick Picture


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DIGITIZING TABLET

This is an input device that enables you to enter drawings and sketches into a computer. A digitizing tablet consists of an electronic tablet and a cursor or pen.

A cursor (also called a puck) is similar to a mouse, except that it has a window with cross hairs for pinpoint placement, and it can have as many as 16 buttons.

A pen (also called a stylus), which looks like a simple ballpoint pen but uses an electronic head instead of ink. The tablet contains electronics that enable it to detect movement of the cursor or pen and translate the movements into digital signals that it sends to the computer.


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For digitizing tablets, each point on the tablet represents a point on the display screen in a fixed manner. This differs from mice, in which all movement is relative to the current cursor position. The static nature of digitizing tablets makes them particularly effective for tracing drawings. Most modern digitizing tablets also support a mouse emulation mode, in which the pen or cursor acts like a mouse. Digitizing tablets are also called digitizers, graphics tablets, touch tablets, or simply tablets.


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DIGITIZING TABLET Picture


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Scanners

Scanner is an input device that can read text or illustrations printed in paper and translate the information into a form that the computer can use. A scanner works by digitizing an image – dividing it into a grid of boxes and representing each box with either a zero or a one, depending on whether the box is filled in (For color and gray scaling, the same principle applies, but each box is then represented by up to 24 bits.). The resulting matrix of bits, called bit map, can then be stored in file, displayed on a screen, and manipulated by programs.


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Optical scanners do not distinguish text from illustration; they represent all images as bit maps. Therefore, you cannot directly edit text that has been scanned. To edit text read by an optical scanner, you need an optical character recognition (OCR) system to translate the image into ASCII character. Most optical scanners sold today come with OCR packages.


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Scanning technology: Most scanners use charge coupled device (CCD) arrays, which consist of tightly packed rows of light receptors that can detect variations in light intensity and frequency. The quality of the CCD array is probably the single most important factor affecting the quality of the scanner. Industry strength drum scanners use a different technology that relies on a photomultiplier tube (PMT), but this type of scanner is much more expensive than the more common CCD based scanners.

Resolution: The denser the bit map, the higher the resolution. Typically, scanners support resolutions 72 to 600 dots per inch (dpi)


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Bit depth. The number of bits used to represent each pixel. The greater the bit depth, the more colors or grayscales can be represented. For a 24 bit color scanner can represent 2 to 24th power (16.7 million) colors,. Note, however, that a large color range is useless if the CCD arrays are capable of detecting only a small number of distinct colors.


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Size and shape. Some scanners are small hand-held devices that you move across the paper. These hand-held scanners are often half-page scanners because they can only scan 2 to 5 inches at a time. Hand-held scanners are adequate of small pictures and photos, but they are difficult to use if you need to scan and entire page of text or graphics. Larger scanners include machines into which you can feed sheets of paper. These are called sheet-fed scanners sheet-fed scanners are excellent for loose sheets of paper, but they are unable to handle bound documents. A second type of large scanner, called a flatbed scanner, is like a photocopy machine. It consists of a board on which you lay books, magazines and the documents that you want to scan.


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Sheet-Fed Scanners


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Flatbed scanner


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DIGITAL CAMERA

Images can be input into a computer using digital camera. These images can then be manipulated in many ways using the various imaging tools available.

The digital camera takes a still photograph stores it and then sends it as digital input into the computer. The images are then stored as digital files.


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Digital Camera Picture


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MAGNETIC INK CHARACTER RECOGNITION (MICR)

Magnetic Ink Character Recognition (MICR) allows the computer to recognize characters printed using magnetic ink. MICR is a direct-entry method used in banks. This technology is used to automatically read those frustrating-looking numbers on the bottom of the cheque. A special purpose machine known as a reader/sorter reads characters made of ink containing magnetized partials. A ranted technology is the magnetic strip, used on the back of credit cards and bank debit cares, that allows readers such as Automated Teller Machines (ATMs) to read account information and facilitate monetary transactions. Another example of magnetic strip technology is in ID card, which can be use for a variety of functions from attendance monitoring to restricting access to specific location.


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MICR Picture


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OPTICAL CHARACTER RECOGNITION (OCR)

Often abbreviated OCR, optical character recognition refers to the branch of computer science that involves reading text from paper and translating the images into a form that the computer can manipulate (for example, into ASCII). An OCR system enables you to take a book or a magazine article and feed it directly into an electronic computer file.

All OCR systems include an optical scanner for reading text, and sophisticated software for analyzing images. Most OCR systems use a combination of hardware (specialized circuit boards) and software to recognize characters, although some inexpensive systems do it entirely through software Advanced’ OCR systems can read text in a large variety of fonts, but they still have difficulty with handwritten text.

The potential of OCR systems is enormous because they enable users to harness the power of computers to access printed documents. OCR is already being used widely in the legal profession, where searches that once required hours or days can now be accomplished in a few seconds.


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OPTICAL MARK RECOGNITION (OMR)

Optical Mark Recognition (OMR) also called mark sensing is a technology where an OMR device senses the presence or absence of a mark, such as a pencil mark. OMR is used in tests such as aptitude tests.


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BAR CODE READER

You are probably familiar with the bar code readers in supermarkets, bookshops, etc. bar-code readers are photoelectric scanners that read the bar codes, or vertical zebra striped marks, printed on product containers. Supermarkets use a bar code system called the Universal Product Code (UPD).

The bard code identifies the product to the supermarket’s computer, which has a description and the latest price of the product. The computer automatically tells the POS (Point of Sales) terminal what the price is.


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Bar Code Reader Picture


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SPEECH INPUT DEVICES

Speech into voice input devices convert a person’s speech into digital form. These input devices when combined with appropriate software, form voice recognition systems. These systems enable users to operate microcomputers using voice commands.

Some of these systems must be ‘trained’ to the particular user’s voice. This is done by his/her spoken words to patterns previously stored in the computer. More advanced systems that can recognize the same word spoken by many different people have been developed. However, until recently the list of words has been limited. A newly developed voice recognition system like IBM Voice Type identifies more than 30,000 words and adapts to individual voices. There are even systems that will translate from one language to another, such as from English to Japanese.


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There are two typed of voice recognition of systems:

a) Continuous Speech

b) Discrete-Word


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Continuous speech Continuous speech recognition systems are use to control a microcomputer’s operations and to issue commands to special application programs for example rather than using the keyword to save a spreadsheet file, user could simply say “Save the file.”

Discrete-Word A common activity in business is preparing memos and other written documents. Discrete-word recognition systems allow to dictate directly into a microcomputer using a microphone. The microcomputer stores the memo in a word processing file where it can be revised later or directly printed out. IBM Voice Type Simply Speaking is an example.


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TOUCH SCREEN

Touch screen is a type of display screen that has a touch sensitive transparent panel covering the screen.

Instead of using a pointing device such as a mouse or light pen, you can use your finger to point directly to objects on the screen.

Although touch screens provide a natural interface for computer novices, they are unsatisfactory for most applications because the finger is such a relatively large object. It is impossible to point accurately to small areas of the screen. In addition, most users find touch-screens tiring to the arms after long use.


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TOUCH PAD

A small, touch-sensitive pad used as a pointing device on some portable computers. By moving a finger or other object along the pad, you can move the pointer on the display screen.


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Touch Pad Picture


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LIGHT PEN

Light pen is an input device that utilizes a light-sensitive detector to select objects on a display screen.

A light pen is similar to a mouse, except that with a light pen you can move the pointer and select objects on the display screen by directly

pointing to the objects with the pen.


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CHAPTER NUMBER 8OUTPUT DEVICES


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INTRODUCTION:

Output is anything that comes out of a computer Output can be meaningful information or gibberish and i can appear in a variety of forms – as binary numbers, as character, as picture, and as print pages.

An output device is any machine capable of representing information from a computer. Output devices include display screens, loudspeakers, printers and plotters etc.


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Monitor

Monitor

Monitor is another term for the display screen. The term monitor, however, usefully refers to the entire box, whereas display screen can mean just the screen. In addition, the term monitor often implies graphic capabilities.


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Classifications of Monitors – Based on Colour:

There are many ways to classify monitors. The most basic is in terms of colour capabilities, which separate monitors into three classes.

Monochrome:

These monitors actually display two colours, one for the background and one for the foreground. The colours can be black and white, green and black or amber and black.


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Grey Scale:

A grey scale monitor is special type of monochrome monitor capable of displaying different shades of grey.


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Types of Monitors

Analog A video monitor that accepts analog signals from the computer's display

adapter, which does the digital-to-analog conversion. An analog monitor may accept only a narrow range of display resolutions; for example, only VGA or VGA and Super VGA, or it may accept a wide range of signals including TV.

Digital A video monitor that accepts a digital signal from the computer and

converts it into analog signals to illuminate the screen. Examples are the earlier MDA, CGA and EGA


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Colour Colour monitors can display anywhere from 16 to over 1 million different

colours. Colours monitors are sometimes called RGB monitors because they accept three separate signals – red green and blue. This differ from colour televisions, for example which use composite video signals in which all colours are mixed together. All colour computer monitors are RGB monitors. An RGB monitor consists of a vacuum tube with three electron guns – one each for red green and blue at one end and the screen at the other end. The three electron guns fire electrons at the screen, which contains a phosphors coating. When the electron beam excite the phosphors, they glow. Depending on which beam excite them, they glow red, green, or blue. Ideally the three beams should coverage for each point on the screen so that each pixel is a combination of three colours.


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Colours and grey scaling monitors are often classified by the number of bits they use to represent each pixel. For example an 8-bit monitor represent each pixel with 8-bits. The more bits are pixel, the more colours and shades of grey the monitor can display.


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Characteristics Of Monitors

Size The most important aspect of a monitor is its screen size. Like

televisions. screen sizes are measured in diagonal inches, the distance from one corner to the opposite corner diagonally. A typical size for small VGA monitors is 14 inches. Monitors that are 16 or more inches diagonally are often called full-page monitors. in addition to their size, monitor can be either portrait (height greater than width) or landscape (width greater than height). Larger landscape monitors can display two full pages, side by side .The screen size is sometimes misleading because there is always an area around the edge of the screen that can't be used therefore, monitor manufacturers must now also state the viewable area, that is ,the area of screen that is actually used.


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Resolution The resolution of a monitor indicates how densely the pixels are packed.

Pixel is short for Picture Element. A Pixel is a single point in a graphic image. Graphics monitors display pictures by dividing the display screen into thousand (or millions) of pixels, arranged in rows and columns. The pixels are so close together that they appear connected. The number of bits used to represent each pixel determined how many colors or shades of gray can be displayed. For example, an 8-bit color monitor uses 8 bits for each pixel making it possible to display 2 to the 8th power (256) different colors of shades of gray.

On color monitors, each pixel is actually composed of three dots-a red , a blue, and a green one. Ideally, the three dots should all converge at the same point, but all monitors have some convergence error that can make color pixels appear fuzzy.


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The quality of display monitor largely depends on its resolution, how many pixels it can display, and how many bits are used to represent each pixel. VGA monitors display 640 by 480, or about 300,000 pixel. in contrast, SVGA monitors display 1,024 by 768 , or nearly 800,000 pixels. True colors monitors use 24 bits per pixel allowing them to display more than 16 million different colors.

In general, the more number of pixels (often expressed in dots per inch). the sharper the image. Most modern monitors can display 1024 by 768 pixels, the SVGA standard. Some high-end models can display 1280 by 1024, or even 1600 by 1200.


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Bandwidth

The amount of data that can be transmitted in fixed amount of time. For digital devices, the bandwidth is usually expressed in bits or bytes per second (bps).For analog devices; the bandwidth is expressed in cycles per second, or Hertz (Hz).


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Interlaced or Non-interlaced Interlacing is a display technique that enables a monitor to provide more

resolution inexpensively. With interlacing monitors, the electron guns draw only half the horizontal lines with each pass ( for example ,all odd lines on one pass and all even lines on the next pass). Because an interlacing monitor refreshes only half the lines at one time, it can display twice as many lines per refresh cycle, giving it greater resolution. Another way of looking at it is that interlacing provides the same resolution as non-interlacing, but less expensively. A shortcoming of interlacing is that the reaction time is slower, so programs that depend on quick refresh rates( animation and video, for example),may experience flickering or streaking. Given two monitors that offer the same resolution, the non-interlacing one will generally be better.


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Refresh Rate

Display monitors must be refreshed many times per second. The refresh rate determines how many times per second the screen is to be refreshed (redrawn). The refresh rate for a monitor is measured in hertz (Hz). The faster the refresh rate, the less the monitor flickers.


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Dot-pitchA measurement that indicates the vertical distance between each pixel on a display screen. Measured in millimeters, the dot pitch is one of the principal characteristics that determine the quality of display monitors. The lower the number, the crisper the image. The dot pitch of colors monitors for personal computers ranges from about 0.15 mm to 0.30 mm. Another term for dot pitch is phosphor pitch.

Convergence Convergence refers to how sharply an individual color pixel on monitor appears. Each pixel is composed of three dots- a red blue, and green one. If the dots are badly misconverged the pixel appear blurry. All monitors have some convergence errors, they differ in degree.


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VIDEO STANDARDS

VGA Abbreviation of video graphics array, a graphics display system for PCs

developed by IBM. VGA has become one of the de facto standards for PCs. in text mode, VGA systems provide a resolution of 720 by 400 pixels. In graphics mode, the resolution is either 640 by 480 ( with 16 colors) or 320 by 200 ( with 256 colors). The total palette of colors is 262,144.

Unlike earlier graphics standard for PCs - CGA ,and EGA ,VGA uses analog signals rather than digital signals. Consequently, a monitor designed for one of the older standard will not be able to use VGA. Since its introduction in 1987 , several other standard have been developed that offer greater resolution and more colors, but VGA remains the lowest common denominator. All PCs made today support VGA, and possibly some other more advanced standard.


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SVGA Short for Super VGA, a set of graphics standards designed to

offer greater resolution than VGA. There are several varieties of SVGA, each providing a different resolution:-

800 by 600 pixels 1024 by 768 pixels 1280 by 1024 pixels 1600 by 1200 pixels


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8514/A

A high-resolution video standard for PCs developed by IBM in 1987. It was designed to extend the capabilities of VGA. The 8514/A/ standard provides a resolution of 1024 by 768 pixels.


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XGA A high-resolution graphics standard introduced by IBM in 1990.

XGA was designed to replace the older 8514/A video standard. It provides the same resolutions (640 by 480 or 1024 by 768 pixels), but supports more simultaneous colors (65 thousand compared to 8514/A's 256 colors).

TI 34010 TI 34010 is a video standard from Texas Instruments chat

supports a resolution of 1024 by 768.


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Printers

PRINTER

Printer is a device that prints text or illustrations on paper and in many cases on transparencies and other media. There are many different types of printers. In terms of the technology utilized, printers fall into the following categories.


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Daisy-Wheel Printer Daisy - wheel printer are a type printer that produces letter-quality type.

A daisy-wheel printer works on the same principle as a ball-head typewriter. The daisy wheel is a disk made of plastic or metal on which characters stand out in relief along the outer edge. To print a character, the printer rotates the disk, forcing the character to hit an ink ribbon, leaving an impression of the character on the paper. You can change the daisy wheel to print different fonts.

Daisy wheel printers cannot print graphics, and in general they are noisy and slow, printing from 10 to about 75 characters per second. As the price of laser and ink-jet printers has declined, and the quality of dot-matrix printers has improved, daisy-wheel printers have become almost obsolete.


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Dot- matrix printer Dot-matrix printers create characters by striking pins against an

ink ribbon. Each pin makes a dot, and combinations of dots form characters and illustrations.

Dot-matrix printers are inexpensive and relatively fast, but they do not produce high-quality output.

Dot-matrix printer vary in two important characteristics: Speed - Given in characters per second (cps), the speed can

vary from about 50 to over 500 cps. Most dot-matrix printers offer different speeds depending on the quality of print desired.

Print quality - Determined by the number of pins (the mechanisms that print the dots), it can vary from 9 to 24. The best dot-matrix printers (24 pins) can produce near letter-quality type, although your can still see a difference.


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Ink-jet printer Ink-jet printer work by spraying ionized ink at a

sheet of paper. magnetized plates ink's path direct the ink onto the paper in the desired shapes. Ink-jet printers are capable of producing high quality print approaching that produced by laser printers. A typical ink-jet printer provides a resolution of 300 dots per inch, although some newer models offer higher resolutions.

In general, the price of ink-jet printers is lower than that of laser printers. However, they are also considerably slower. Another drawback of ink-jet printers is that they require a special type of ink that is apt to smudge on inexpensive copier paper.


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Laser Printer Laser printer utilizes a laser beam to produce an image on a

drum. The drum is than rolled through a reservoir of toner, which is picked up by the charged portions of the drum. Finally, the toner is transferred to the paper through a combination of heat and pressure. This is also the way copy machines work.

Because an entire page is transmitted to a drum before the toner is applied , laser printers are sometimes called page printers. There are two other types of page printers even through they do not use lasers at all. One uses an array of LEDs to expose the drum, and the other uses LCDs. Once the drum is charged, however, they both operate like a real laser printer.


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LCD and LED Printers

Similar to laser printer but uses liquid crystals or light-emitting diodes rather than a laser to produce and image on the drum.

Line Printer Line printer are high-speed printers capable of printing an entire

line at one time. A fast line printer can print as many as 3000 lines per minute. The disadvantage of line printer are that they can print only one font, they cannot print graphics, the print quality is low, and they are very noisy.


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Thermal Printer Thermal printers are printers that produce images by

pushing electrical heated pins against special heat-sensitive paper. Thermal printers are inexpensive and are used in most calculators and many fax machines. They produce low-quality print, and the paper tends to curl and fade after a few weeks or months.


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SOUND CARDS & SPEAKERS

An expansion board that enables a computer to manipulate and output sounds. Sound cards are necessary for nearly all CD-ROMs and have become commonplace on modern personal computers. Sound cards enable the computer to output sound through speakers connected to the board, to record sound input from a microphone connected to the computer, and manipulate sound stored on disk.

Nearly all sound cards support MIDI, a standard for representing music electronically. In addition, most sound cards are Sound Blaster-compatible, which means that they can process commands written for a Sound Blaster card, the de facto standard for PC sound.


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CHAPTER NUMBER 9NETWORKS


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LANS

A local area network (LAN) is the communication of a number of computers by cable connecting to each one in a single location, usually a single floor of a building or all the computers in a small company. LANs may be contrasted with wide area networks (WANs). Stated simply, WANs are the communication between LANs by telephone lines leased from the various telephone companies, satellite links, packet radio, or microwave transceivers.


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MAN

A Metropolitan Area Network (MAN) covers larger geographic areas, such as cities or school districts. By interconnecting smaller networks within a large geographic area, information is easily disseminated throughout the network. Local libraries and government agencies often use a MAN to connect to citizens and private industries. One example of a MAN is the MIND Network located in Pasco County, Florida. It connects all of Pasco's media centers to a centralized mainframe at the district office by using dedicated phone lines, coaxial cabling, and wireless communications providers.


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WAN

WANs are private and owned by the business that operates with them. The Internet has emerged as both the largest and the least expensive WAN in the world recently. Many companies take advantage of it now by forming private WANs, known as VPNs, or Virtual Private Networks, through encrypted communications

over the Internet.


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Network administrator has full rights and permissions to all resources on a network. The administrator is usually responsible for installing, managing, and controlling servers and networking components. Administrators can also modify the properties of user accounts and the membership of groups, create and manage security printers, install printers, share resources, and assign permissions to those resources


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Advantages of Networks

a)Sharing information: the computer can help you centralize the information and maintain control over it if you select one computer to store the shared information and have all other computers reference the information on that computer over the network.

b)Sharing hardware resources: a network allows anyone connected to the network to use printers, fax modem, scanners, tape backup units or almost any other device that can be attached to a computer.


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d)Preserving information: a network also allows for information to be backed up to a central location. It is difficult to maintain regular backups on a number of stand-alone computers so important information can be lost easily by mistake or by accident.

e)Protecting information: a network provides a more secure environment for a company's important information than stand-alone computers. Networks provide an additional layer of security by way of passwords.

f) Electronic-mail (e-mail): the computer network can also help

people communicate by e-mail. You can attach electronic documents to mail message like photo, sound and video clip.


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Network Type

Server-based (also called client-server) networks are defined by the presence of servers on a network that provide security and administration of the networks. It consists with many clients and one or more servers. Clients (often called the "front end") request services, such as file storage and printing, and servers (often called the "back end") deliver them.


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Advantages Of Client Server

a) Central file storage, which allows all users to work form the same set of data and provides easy backup of critical data and keeps data from getting lost among computers

b) Ability of servers to pool available hardware and software, lowering overall costs

c) Optimized dedicated servers, which are faster than peers at sharing network

d) Freeing of users from the task of managing network

e )Easy manageability of a large number of users

f)Ability to share expensive equipment, such as laser printers

g) Less intrusive strong central security, since a single password need to access all shared resources on the network


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Disadvantages of Client Server

a) Expensive dedicated hardware

b) Expensive network operating system software and client licenses

c) A dedicated network administrator (usually required)


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Peer Networks

Every computer on peer network is equal and can communicate with any other computer on the network to which it has been granted access rights. So basically, every computer on peer network functions as both a server and a client. The peer network is more common in small business.


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Advantages of Peer to Peer

a) No extra investment for server software and hardware are needed

b)No network administrator is needed

c)Easy setup

d)Lower cost


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Disadvantages of Peer to Peer

a) Additional load on computers for resource sharing

b) Lack of central organization, which can make data hard to find

c) Users must administer their own computers

d) Weak and intrusive security


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Hybrid Networks

Hybrid networks have all three types of computers and have active domains and workgroups. This means that network users have access to any resources being shared by peers in their workgroup while most shared resources are located on servers.

The advantages of hybrid networks are same as the advantages of server-based and peer-based networks. Hybrid network shares the disadvantages of server-based network.


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Server Type

File Server File servers offer the services, which are the network applications that store, retrieve, and move data. With a file server, users can exchange, read, write, and manage shared files and the data contained in them.

Print Server Print server manages and control printing on a network and also offers fax service. The print server allow multiple and simultaneous access to print and fax services. The network operating system achieves this by using print and fax queues. The queues are special storage areas where printing and faxing jobs are stored and then sent to the printer or fax device in an organized fashion.


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Application Server Application server allows a client on network to access and use extra computing power and expensive software applications on a shared computer. Application servers are used when efficiency and security requires a program to stay close to the data, and the data stays in one place.

Message Server Message servers allow a wide variety of communication methods that are much complex than a simple file server can handle. Data can take the form of graphics, digitized video, or audio, text and binary. Message servers must coordinate the complex interactions between users, documents, and applications.


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Database Server

Database server is one of application server. Database server allows a network with powerful database capabilities. So, users of a relatively

weak client can enjoy the same power of database servers.


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Network Topology

Network topology are the physical layout of the network that the locations of the computers and how the cable is run between them. It is important to use the right topology. Each topology has its own strengths and weakness.


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Bus topology

A bus topology connects computers along a single or more cable to connect linearly as figure 1. A network that uses a bus topology is referred to as a "bus network" which was the original form of Ethernet networks. Ethernet 10Base2 (also known as thinnet) is used for bus topology.


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Bus topology is the cheapest way of connecting computers to form a workgroup or departmental LAN, but it has the disadvantage that a single loose connection or cable break can bring down the entire LAN


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Termination is important issue in bus networks. The electrical signal from a transmitting computer is free to travel the entire length of the cable. Without the termination, when the signal reaches the end of the wire, it bounces back and travels back up the wire. When a signal echoes back and forth along an unterminated bus, it is called ringing. The terminators absorb the electrical energy and stop the reflections.


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Advantages of the bus are following. 1) Bus is easy to use and understand and inexpensive simple network 2) It is easy to extend a network by adding cable with a repeater that boosts the signal and allows it to travel a longer distance.

Disadvantages are following. 1) A bus topology becomes slow by heavy network traffic with a lot of computer because networks do not coordinate with each other to reserve times to transmit. 2) It is difficult to troubleshoot a bus because a cable break or loose connector will cause reflections and bring down the whole network.


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Star topology

A star topology links the computers by individual cables to a central unit, usually a hub as in figure 2. When a computer or other networking component transmits a signal to the network, the signal travels to the hub. Then, the hub forwards the signal simultaneously to all other components connected to the hub. Ethernet 10BaseT is a network based on the star topology. Star topology is the most popular way to connect computers in a workgroup or

departmental network.

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Advantages of star topology are such as:a) The failure of a single computer or cable doesn't bring down the entire network. b) The centralized networking equipment can reduce costs in the long run by making network management much easier. c) It allows several cable types in same network with a hub that can accommodate multiple cable types.

Disadvantages of star topology are such as: a) Failure of the central hub causes the whole network failure. b) It is slightly more expensive than using bus topology.

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Ring topology

A ring topology connects the computers along a single path whose ends are joined to form a circle as figure 3. The circle might be logical only but the physical arrangement of the cabling might be similar to star topology, with a hub or concentrator at the center. The ring topology is commonly used in token ring networks that the ring of a token ring network is concentrated inside a device called a Multistation Access Unit (MAU) and fiber Distributed Data Interface (FDDI) networks that the ring in this case is both a physical and logical ring and usually runs around a campus or collection of buildings to form a high-speed backbone network.


04/07/23 Intro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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Advantages are following: a) One computer cannot monopolize the network. b) It continue to function after capacity is exceeded but the speed will be slow.

Disadvantages are following: a) Failure of one computer can affect the whole network. b) It is difficult to troubleshoot. c) Adding and removing computers disrupts the network.


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Mesh topology

In a mesh topology, each computer on network has redundant data paths as showing in figure. The mesh topology provides fault tolerance-if a wire, hub, switch, or other component fails, data can travel along an alternate path. A diagram of a mesh network looks like a fishing net. A mesh topology is most often used in large backbone networks in which failure of a single switch or router can result in a large portion of the network going down.



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CABLING IN NETWORKS


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Unshielded Twisted Pair (UTP)

Cable Twisted pair cabling comes in two varieties: shielded and unshielded. Unshielded twisted pair (UTP) is the most popular and is generally the

best option for school networks (See following figure).


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The quality of UTP may vary from telephone-grade wire to extremely high-speed cable. The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. The EIA/TIA (Electronic Industry Association/Telecommunication Industry Association) has

established standards of UTP and rated five categories of wire.


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CAT1 (Voice Only) CAT2 (Data to 4Mbps) CAT3 (Data to 10 Mbps) CAT4 (Data to 20 Mbps) CAT5 ( Data to 100 Mpbs)


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One difference between the different categories of UTP is the tightness of the twisting of the copper pairs. The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot. Buy the best cable you can afford; most schools purchase Category 3 or Category 5. Category

5 cable is highly recommended.


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If you are designing a 10 Mbps Ethernet network and are considering the cost savings of buying Category 3 wire instead of Category 5, remember that the Category 5 cable will provide more "room to grow" as transmission technologies increase. Both category 3 and category 5 UTP have a maximum segment length of 100 meters.


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Unshielded Twisted Pair Connector

The standard connector for unshielded twisted pair cabling is an RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector (See fig). A slot allows the RJ-45 to be inserted only one way. RJ stands for Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. This standard designates which wire goes with each pin inside the connector.


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RJ 45 Connector

Fig.2. RJ-45 connector


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Shielded Twisted Pair (STP) Cable

A disadvantage of UTP is that it may be susceptible to radio and electrical frequency interference. Shielded twisted pair (STP) is suitable for environments with electrical interference; however, the extra shielding can make the cables quite bulky. Shielded twisted pair is often used on networks using Token Ring topology.


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Coaxial Cable

Coaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield (See fig). The metal shield helps to block any outside interference from fluorescent lights, motors,

and other computers.



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Although coaxial cabling is difficult to install, it is highly resistant to signal interference. In addition, it can support greater cable lengths between network devices than twisted pair cable. The two types of coaxial cabling are: thick coaxial and thin coaxial.


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Thin coaxial cable is also referred to as thinnet. 10Base2 refers to the specifications for thin coaxial cable carrying Ethernet signals. The 2 refers to the approximate maximum segment length being 200 meters. In actual fact the maximum segment length is 185 meters. Thin coaxial cable is popular in school

networks, especially linear bus networks.


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Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the specifications for thick coaxial cable carrying Ethernet signals. The 5 refers to the maximum segment length being 500 meters. Thick coaxial cable has an extra protective plastic cover that helps keep moisture away from the center conductor. This makes thick coaxial a great choice when running longer lengths in a linear bus network. One disadvantage of thick coaxial is that it does not bend easily and is difficult to install.


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Coaxial Cable Connectors

The most common type of connector used with coaxial cables is the Bayone-Neill-Concelman (BNC) connector (See fig). Different types of adapters are available for BNC connectors, including a T-connector, barrel connector, and terminator. Connectors on the cable are the weakest points in any network. To help avoid problems with your network, always use the BNC connectors that

crimp, rather than screw, onto the cable.


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BNC Connector


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Fiber Optic Cable

Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials (See fig). It transmits light rather than electronic signals, eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting.


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Fiber optic cable has the ability to transmit signals over much longer distances than coaxial and twisted pair. It also has the capability to carry information at vastly greater speeds. This capacity broadens communication possibilities to include services such as video conferencing and interactive services. The cost of fiber optic cabling is comparable to copper cabling; however, it is more difficult to install and modify. 10BaseF refers to the specifications for fiber optic cable carrying Ethernet signals.


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Facts about fiber optic cables: Outer insulating jacket is made of Teflon or PVC. Kevlar fiber helps to strengthen the cable and prevent breakage. A plastic coating is used to cushion the fiber center. Center (core) is made of glass or plastic fibers.


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Insulating Jacket Kevlar Fiber

PlasticCoating

Center CoreMade of

Glass


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Fiber Optic Connector

The most common connector used with fiber optic cable is an ST connector. It is barrel shaped, similar to a BNC connector. A newer connector, the SC, is becoming more popular. It has a squared face and is easier to connect in a confined space.


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Fiber Optics Connector


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Ethernet Cable Summary

Specification Cable Type Max Length 10Base T UTP 100 Meters 10 Base 2 Thin Coaxial Cable 185m 10 Base 5 Thick Coaxial Cable 500 m 10 Base F Fiber Optics Cable 2000m


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What is Ethernet Ethernet is a standard communications protocol embedded in software

and hardware devices, intended for building a local area network (LAN). What is Internet Internet refers to the world-wide collection of independent networks,

connected via routers to each other for communication purposes. What is Intranet Intranet refers to a collection of networks within a logical body, such as a

building, corporation or other entity. Intranets can be as simple as two computers connected at home to each other, or as vast as 1000 branch offices of a bank, connected via privately owned, non-public network links.


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Making of Wireless Network


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Steps to set up your home wireless network

1.Choose your wireless equipment

The first step is to make sure that you have the equipment you need.

Shopping list

• Broadband Internet connection

• Wireless router

• A computer with built-in wireless networking support or a wireless network adapter


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A wireless router

The router converts the signals coming across your Internet connection into a wireless broadcast, sort of like a cordless phone base station. Be sure to get a wireless router.

2.Connect your wireless router Since you'll be temporarily disconnected from the Internet, print these

instructions before you go any further. First, locate your cable modem or DSL modem and unplug it to turn it

off. Next, connect your wireless router to your modem. Your modem should

stay connected directly to the Internet. Later, after you've hooked everything up, your computer will wirelessly connect to your router, and the router will send communications through your modem to the Internet.


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Next, connect your router to your modem:


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Next, connect your router to your modem:

• If you currently have your computer connected directly to your modem: Unplug the network cable from the back of your computer, and plug it into the port labeled Internet, WAN, or WLAN on the back of your router.

• If you currently have your computer connected to a router: Unplug the network cable connected to the Internet, WAN, or WLAN port from your current router, and plug this end of the cable into the Internet, WAN, or WLAN port on your wireless router. Then, unplug any other network cables, and plug them into the available ports on your wireless router. You no longer need your original router, because your new wireless router replaces it.


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Next, plug in and turn on your cable or DSL modem. Wait a few minutes to give it time to connect to the Internet, and then plug in and turn on your wireless router. After a minute, the Internet, WAN, or WLAN light on your wireless router should light up, indicating that it has successfully connected to your modem.



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3.Configure your wireless router

Using the network cable that came with your wireless router, you should temporarily connect your computer to one of the open network ports on your wireless router (any port that isn't labeled Internet, WAN, or WLAN). If you need to, turn your computer on. It should automatically connect to your router.


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Next, open Internet Explorer and type in the address to configure your router.

You might be prompted for a password. The address and password you use will vary depending on what type of router you have, so refer to the instructions included with your router.

As a quick reference, this table shows the default addresses, usernames, and passwords for some common router manufacturers.


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Router Address Username Pass 3Com http://192.168.1.1 admin admin D-Link http://192.168.0.1 admin Linksys http://192.168.1.1 admin admin


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Internet Explorer will show your router's configuration page. Most of the default settings should be fine, but you should configure three things:

1.Your wireless network name, known as the SSID. This name identifies your network. You should choose something unique that none of your neighbors will be using.

2.Wireless encryption (WEP) or Wi-Fi Protected Access (WPA), which help protect your wireless network. For most routers, you will provide a passphrase that your router uses to generate several keys. Make sure your passphrase is unique and long (you don't need to memorize it).

3.Your administrative password, which controls your wireless network. Just like any other password, it should not be a word that you can find in the dictionary, and it should be a combination of letters, numbers, and symbols. Be sure you can remember this password, because you'll need it if you ever have to change your router's settings.


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The exact steps you follow to configure these settings will vary depending on the type of router you have. After each configuration setting, be sure to click Save Settings, Apply, or OK to save your changes.

Now, you should disconnect the network cable from your computer.


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4.Connect your computers If your computer does not have wireless network support built in,

plug your network adapter into your USB port, and place the antenna on top of your computer (in the case of a desktop computer), or insert the network adapter into an empty PC card slot (in the case of a laptop). Windows XP will automatically detect the new adapter, and may prompt you to insert the CD that came with your adapter. The on-screen instructions will guide you through the configuration process.


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Note: The steps below only apply if you're using Windows XP Service Pack 2. If you're running Windows XP and you don't have Service Pack 2 yet, plug your computer into your wireless router and download and install Windows XP Service Pack 2.

Windows XP should show an icon with a notification that says it has found a wireless network.


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Windows XP should show an icon with a notification that says it has found a wireless network.


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Follow these steps to connect your computer to your wireless network:

1.Right-click the wireless network icon in the lower-right corner of your screen, and then click View Available Wireless Networks. If you run into any problems, consult the documentation that came with your network adapter. Don't be afraid to call their tech support.

2.The Wireless Network Connection window should appear and you should see your wireless network listed with the network name you chose. If you don't see your network, click Refresh network list in the upper-left corner. Click your network, and then click Connect in the lower-right corner.


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network, click Refresh network list in the upper-left corner. Click your network, and then click Connect in the lower-right corner.


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3.Windows XP prompts you to enter a key. Type the encryption key that you wrote down earlier in both the Network key and Confirm network key boxes, and then click Connect.

4.Windows XP will show its progress as it connects to your network. After you're connected, you can now close the Wireless Network Connection window. You're done.

Note: If the Wireless Network Connection window continues to show Acquiring Network Address, you may have mistyped the encryption key.


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Networking Components


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Cables Network Adapter Card Hub Switch Bridge


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NIC


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HUB

The central connecting device is called a hub. A hub is a box that is used to gather groups of PCs together at a central location with 10BaseT cabling. If you're networking a small group of computers together, you may be able to get by with a hub, some 10BaseT cables, and a handful of network adapters. Larger networks often use a thin coax "backbone" that connects a row of 10BaseT hubs together. Each hub, in turn, may connect a handful of computer together using 10BaseT cabling, which allows you to build networks of tens, hundreds, or thousands of computers.

Like network cards, hubs are available in both standard (10Mbps) and

Fast Ethernet (100Mbps) versions.


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Like network cards, hubs are available in both standard (10Mbps) and Fast Ethernet (100Mbps) versions.


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SWITCH

The Switching hub, sometimes called a "Switch" is a more advanced unit over the basic hub. In a basic hub, all the computers connect to it and the speed of the network is defined by the slowest computer network card connected. If you have 10 100Mbps cards on the network and just on 10Mbps card, the system cannot run faster than that one 10Mbps card. There in comes the Switching hub. This hub treats each network card independently and in the matter of the 10 100Mbps network with the one 10Mbps network card, the Switching hub allows all of the faster connections to remain at the higher speed and still interact

with the 10Mbps system.


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Bridge

In telecommunication networks, a bridge is a product that connects a local area network (LAN) to another local area network that uses the same protocol (for example, Ethernet or Token Ring). You can envision a bridge as being a device that decides whether a message from you to someone else is going to the local area network in your building or to someone on the local area network in the building across the street. A bridge examines each message on a LAN, "passing" those known to be within the same LAN, and forwarding those known to be on the other interconnected LAN (or LANs).


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Gateway

A node on a network that serves as an entrance to another network. In enterprises, the gateway is the computer that routes the traffic from a workstation to the outside network that is serving the Web pages. In homes, the gateway is the ISP that connects the user to the internet. In enterprises, the gateway node often acts as a proxy server and a firewall. The gateway is also associated with both a router, which use headers and forwarding tables to determine where packets are sent, and a switch, which provides the actual path for the packet in and out of the gateway.


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Router

A device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP’s network. Routers are located at gateways, the places where two or more networks connect.


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Layers in Network

OSI Model 7 Application layer 6 Presentation layer 5 Session layer 4 Transport layer 3 Network layer 2 Data link layer LLC sublayer MAC sublayer 1 Physical layer


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Chapter Number 10Introduction to Telecommunication


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Introduction of TelecommunicationAnalogue Signals

Digital Signals

Discrete Signals

Continuous Signals

Frequency Domain

Time Domain

Bit Rate

Sampling Rate

Sampling Frequency


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Analogue Signals

An analog or analogue signal is any time continuous signal where some time varying feature of the signal is a representation of some other time varying quantity. It differs from a digital signal in that small fluctuations in the signal are meaningful.

For example, in sound recording, fluctuations in air pressure (that is to say, sound) strike the diaphragm of a microphone which causes corresponding fluctuations in a voltage or the current in an electric circuit. The voltage or the current is said to be an "analog" of the sound.


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Digital Signals

The term digital signal is used to refer to more than one concept. It can refer to discrete-time signals that have a discrete number of levels, for example a sampled and quantified analog signal, or to the continuous-time waveform signals in a digital system, representing a bit-stream.


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Discrete Time Signal

A discrete signal or discrete-time signal is a time series, perhaps a signal that has been sampled from a continuous-time signal. Unlike a continuous-time signal, a discrete-time signal is not a function of a continuous-time argument, but is a sequence of quantities; that is, a function over a domain of discrete integers. Each value in the sequence is called a sample.


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Digital Signal

Discrete Signal Intro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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Continuous Signal

A continuous signal or a continuous-time signal is a varying quantity (a signal) that is expressed as a function of a real-valued domain, usually time. The function of time need not be continuous.

Infinite Signal

Finite Signal


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Sample

In signal processing, sampling is the reduction of a continuous signal to a discrete signal. A common example is the conversion of a sound wave (a continuous-time signal) to a sequence of samples (a discrete-time signal).

A sample refers to a value or set of values at a point in time and/or space.


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Time Domain Signal

Time domain is a term used to describe the analysis of mathematical functions, or physical signals, with respect to time. In the time domain, the signal or function's value is known for all real numbers, for the case of continuous time, or at various separate instants in the case of discrete time.


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Frequency Domain

Frequency domain is a term used to describe the analysis of mathematical functions or signals with respect to frequency.


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Bit rate

In telecommunications and computing, bit rate (sometimes written bit rate, data rate or as a variable R or fb) is the number of bits that are conveyed or processed per unit of time.

The bit rate is quantified using the 'bits per second' (bit/s or bps) unit, often in conjunction with a SI prefix such as kilo- (kbit/s or kbps), mega-(Mbit/s or Mbps), giga-(Gbit/s or Gbps) or tera (Tbit/s or Tbps).


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HTMLIntro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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What Is the World Wide Web?

the World Wide Web as a global, dynamic, cross-platform, distributed, graphical hypertext information system that runs over the Internet.


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Hypertext Information System

The idea behind hypertext is that instead of reading text in a rigid, linear structure (such as a book).

you can skip easily from one point to another. You can get more information, go back, jump to other topics, and navigate through the text based on what interests you at the time.


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The Web Is Graphical and Easy To Navigate

One of the best parts of the Web, and arguably the reason it has become so popular, is its ability to display both text and graphics in full color on the same page.

The Web provides capabilities for graphics, sound, and video to be incorporated with the text, and newer software includes even more capabilities for multimedia and embedded applications.

More importantly, the interface to all this is easily navigable-just jump from link to link, from page to page, across sites and servers.


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The Web Is Cross-Platform

Cross-platform means that you can access Web information equally well from any computer hardware running any operating system using any display.


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BROWSER

A browser is used to view and navigate Web pages and other information on the World Wide Web.

like Netscape's Navigator or Microsoft's Internet Explorer.


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The Web Is Distributed

Information takes up lot of space, particularly when you include images and multimedia capabilities. To store all the information that the Web provides, you'd need huge amount of disk space, and managing it would be almost impossible.

The Web is successful in providing so much information because that information is distributed globally across thousands of Web sites,


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Web site

A Web site is a location on the Web that publishes some kind of information. When you view a Web page, your browser is connecting to that Web site to get that information.


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(URL)

A Uniform Resource Locator (URL) is a pointer to a specific bit of information on the Internet.


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The Web Is Dynamic

Because information on the Web is contained on the site that published it, the people who published it in the first place can update it at any time.


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Web Servers

A Web server is the program that runs on a Web site and is responsible for replying to Web browser requests for files.

You need a Web server to publish documents on the Web


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simple terminology First, here's a look at some simple

terminology I'll be using throughout. You need to know what the following terms mean and how they apply to the body of work you're developing for the Web:

The Web presentation The Web site Web pages Home pages


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A Web presentation is a collection of one or more Web pages.

A Web page is a single element of a Web presentation and is contained in a single disk file.

The home page is the entry or starting point for the rest of your Web presentation.


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What Do You Want To Do on the Web?

Your content is the stuff you're putting on the Web. Information, fiction, images, art, programs, humor, diagrams, games-all of this is content.


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What HTML Is…


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Features Of HTML

HTML stands for Hypertext Markup Language.


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HTML Is a Markup Language

HTML is a markup language. Writing in a markup language means that you start with the text of your page and add special tags around words and paragraphs.

HTML has a defined set of tags you can use. You can't make up your own tags to create new

appearances or features.


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HTML tags HTML tags are the things inside brackets (<>)

that indicate features or elements of a page. <TheTagName> affectedtext </TheTagName> All HTML tags are case-insensitive; that is, you

can specify them in uppercase, lowercase, or in any mixture. So, <HTML> is the same as <html> is the same as <HtMl>.


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Create an HTML page. To get started writing HTML, you're not going

to need a Web server, a Web provider, or even a connection to the Web itself.

All you really need is something to create your HTML files, and at least one browser to view them.

you'll need a text editor. A text editor is a program that saves files in ASCII format. ASCII format is just plain text, with no font formatting or special characters.


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How To Save File

The filename should have an extension of .html (.htm on DOS or Windows systems that have only three-character extensions), for example, myfile.html or text.html or index.htm..

Use small, simple names. Don't include spaces or special characters (bullets, accented characters)-just letters and numbers are fine.



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View the result

Open Microsoft's Internet Explorer. Go view menu item Select source Browse your selected html file Last ,refresh the page.


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Structuring Your HTML

<HTML> The first page structure tag in every HTML

page is the <HTML> tag. It indicates that the content of this file is in the HTML language.

All the text and HTML commands in your HTML page should go within the beginning and ending HTML tags, like this:

<HTML>...your page...</HTML>


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<HEAD> The <HEAD> tag specifies that the lines within the

beginning and ending points of the tag are the introduction to the rest of the file.

There generally are only a few tags that go into the <HEAD> portion of the page (most notably, the page title, described later).

You should never put any of the text of your page into the header.

<HTML><HEAD><TITLE>This is the Title.</TITLE></HEAD>....</HTML> Intro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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<BODY> The remainder of your HTML page, including all the text

and other content (links, pictures, and so on) is enclosed within a <BODY> tag.

<HTML><HEAD><TITLE>This is the Title</TITLE> </HEAD><BODY>....</BODY></HTML>


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Tags sequence <HTML><HEAD></HEAD><BODY></BODY></HTML>)

make sure whenever you close an HTML tag that you're closing the most recently opened tag.


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The Title

Each HTML page needs a title to indicate what the page describes .

<TITLE> tags always go inside the page header <HTML><HEAD><TITLE>The Lion, The Witch, and the Wardrobe</TITLE> </HEAD><BODY>....</BODY></HTML>

You can have only one title in the page


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Headings

Headings are used to divide sections of text . HTML defines six levels of headings.

Heading tags look like this: <H1>Home Page</H1> The numbers indicate heading levels (H1

through H6). 1 is largest and 6 is smallest.


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Paragraphs

Now that you have a page title and several headings, let's add some ordinary paragraphs to the page.

<P>lines you want to display on page</P>


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Lists HTML defines THREE kinds of lists: Numbered, or ordered lists, typically labeled

with numbers Bulleted, or unordered lists, typically labeled

with bullets or some other symbol Glossary lists, in which each item in the list

has a term and a definition for that term, arranged so that the term is somehow highlighted or drawn out from the text


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Numbered Lists Numbered lists are surrounded by the <OL>...</OL> tags (OL

stands for Ordered List). And each item within the list begins with the <LI> (List Item) tag. The <LI> tag is one-sided; you do not have to specify the closing

tag . <P>To summon the demon, use the following steps:</P>

<OL>1<LI>Draw the pentagram<LI>Sacrifice the goat<LI>Chant the incantation</OL>


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figure


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Unordered Lists Unordered lists are lists in which the elements

can appear in any order. Unordered lists look just like ordered lists in

HTML except that the list is indicated using <UL>...</UL> tags instead of OL.

<P>The three Erinyes, or Furies, were:</P><UL><LI>Tisiphone<LI>Megaera<LI>Alecto</UL>


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Figure


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Glossary Lists

Glossary lists, sometimes called definition lists, are slightly different from other lists. Each list item in a glossary list has two parts:

A term That term's definition


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Each part of the glossary list has its own tag: <DT> for the term ("definition term") <DD> for its definition ("definition definition"). <DT> and <DD> are both one-sided tags The entire glossary list is indicated by the

tags <DL>...</DL> ("definition list").


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Example

<DL><DT>Basil<DD>Annual. Can grow four feet high; the scent of its tiny white flowers is heavenly.<DT>Oregano<DD>Perennial. Sends out underground runners and is difficult to get rid of once established.<DT>Coriander<DD>Annual. Also called cilantro, coriander likes cooler weather of spring and fall.</DL>


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figure


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Nesting Lists What happens if you put a list inside another list?

This is fine as far as HTML is concerned; just put the entire list structure inside another list as one of its elements.

<H1>Peppers</H1><UL><LI>Bell<LI>Chile <UL> <LI>Serrano <LI>Jalapeno <LI>Habanero <LI>Anaheim </UL><LI>Szechuan<LI>Cayenne</UL> Intro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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FIGURE


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make a page


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Character Styles

To change the appearance of a set of characters within text, you can use:

physical styles.


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Physical Styles Physical style tags indicate exactly the way text is to

be formatted (bold, underline). Like the character style tags, each formatting tag

has a beginning and ending tag. <B> Bold

<I> Italic <TT> Moonscape typewriter font

<U> Underline <BIG> Bigger print than the surrounding text<SMALL> Smaller print<SUB> Subscript <SUP> Superscript


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Example <P>In Dante's <I>Inferno</I>, malaboge was the eighth circle of

hell,and held the malicious and fraudulent.</P><P>All entries must be received by <B>September 26, 1996</B>.</P><P>Type <TT>lpr -Pbirch myfile.txt</TT> to print that file.</P><P>Sign your name in the spot marked <U>Sign Here</U>:</P> <P>People who wear orange shirts and plaid pants are fashion-challenged.</P><P>RCP floor mats give you <BIG>BIG</BIG> savings over the competition!</P><P>Then, from the corner of the room, he heard a <SMALL>tiny voice</SMALL>.</P><P>In heavy trading today. Consolidated Orange Trucking rose <SUP>1</SUP>/<SUB>4</SUB>points on volume of 1,457,900 shares.</P>



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nest character tags

You can nest character tags-for example, use both bold and italic for a set of characters-like this:

<B><I>Text that is both bold and italic</I></B>


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Fonts and Font Sizes

The most common use of the <FONT> tag is to change the size of the font for a character, word, phrase, or on any range of text.

The <FONT>...</FONT> tags enclose the text, and the SIZE attribute indicates the size to which the font is to be changed.

The values of SIZE are 1 to 7, with 3 being the default size. Look at the following example:

<P>Bored with your plain old font? <FONT SIZE=5>Change it.</FONT></P>


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You can also specify the size in the <FONT> tag as a relative value using the + or - characters in the value for SIZE.

Because the default size is 3, you can change relative font sizes from -3 to +4, like this:

<P>Change the <FONT SIZE=+2>Font</FONT> size again.</P>


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Changing the Font Face

FACE takes as its value a set of font names, surrounded by quotes and separated by commas.

<P><FONT FACE="Times New Roman "> on the strokes of the characters. </FONT></P>


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Special List Formats Normally, when you create lists in HTML, the browser determines

the size and type of the bullet in an unordered list. For unordered lists (the <UL> tag), the TYPE attribute indicates

the type of bullet used to mark each item. The possible values are as follows:

TYPE=DISC A solid bullet (the default)TYPE=CIRCLE A hollow bulletTYPE=SQUARE A square hollow bullet


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Example

<UL TYPE=SQUARE><LI>The Bald Soprano<LI>The Lesson<LI>Jack <LI>The Chairs</UL>


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For ordered lists

For ordered lists (the <OL> tag), the TYPE attribute also applies but has a different set of values that indicate the numbering scheme used for the list:


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Example

<OL TYPE=I><LI>Income <OL TYPE=1> <LI>Wages, Salaries and other Earnings <LI>Interest and Dividend Income <LI>Gains and Losses </OL><LI>Itemized Deductions<LI>Figuring your Tax</OL>


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Horizontal Rules

The <HR> tag, which has no closing tag and no text associated with it, creates a horizontal line on the page.

Rule lines are excellent for visually separating sections of the Web page.


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Example


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Line Break

The <BR> tag breaks a line of text at the point where it appears.

<P>Tomorrow, and tomorrow, and tomorrow<BR>Creeps in this petty pace from day to day<BR>Told by an idiot, full of sound and fury, <BR>Signifying nothing.</P>



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Text Alignment

Text alignment is the ability to arrange a block of text such as a heading or a paragraph so that it is aligned against the

left margin (left justification, the default). aligned against the right margin (right

justification). or centered.


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Aligning Individual Elements To align an individual heading or paragraph, use the

ALIGN attribute to that HTML element.

Example

<H1 ALIGN=LEFT>Serendipity Products</H1> <H2 ALIGN=RIGHT><A HREF="who.html">Who We Are</A></H2><H2 ALIGN=RIGHT><A HREF="products.html">What We Do</A></H2>


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Aligning Blocks of Elements

A slightly more flexible method of aligning text elements is to use the <DIV> tag.

<DIV> stands for division, and includes the ALIGN attribute just as headings and paragraphs do .

DIV needs to be used only once, rather than including ALIGN repeatedly in several different tags.


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Example <DIV ALIGN=RIGHT>

<H2><A HREF="who.html">Who We Are</A></H2> <H2><A HREF="products.html">What We Do</A></H2> <H2><A HREF="contacts.html">How To Reach Us</A></H2></DIV>


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Preformatted Text


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<PRE> Diameter Distance Time to Time to (miles) from Sun Orbit Rotate (millions of miles)------------------------------------------------------------------- Mercury 3100 36 88 days 59 daysVenus 7700 67 225 days 244 daysEarth 7920 93 365 days 24 hrsMars 4200 141 687 days 24 hrs 24 minsJupiter 88640 483 11.9 years 9 hrs 50 minsSaturn 74500 886 29.5 years 10 hrs 39 minsUranus 32000 1782 84 years 23 hrsNeptune 31000 2793 165 days 15 hrs 48 minsPluto 1500 3670 248 years 6 days 7 hrs</PRE>


04/07/23

Creating Links

To create a link in HTML, you need two things: The name of the file (or the URL of the file) you want

to link to The text that will serve as the "hot spot"-that is, the

text that will be highlighted in the browser, which your readers can then select to follow the link

Only the second part is actually visible on your page. When your reader selects the text that points to a link, the browser uses the first part as the place to "jump" to.


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The Link Tag <A> To create a link in an HTML page, you use

the HTML link tag <A>...</A>. The <A> tag is often called an anchor tag. The most common use of the link tag,

however, is to create links to other pages.


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Example

<A HREF="../menu.html">Main Menu</A>


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Note

When you include tags inside other tags, make sure that the closing tag closes the tag that you most recently opened. That is, do this:<P> <A> ………</A> </P>


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Using Images Colorand Backgrounds


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Images on the Web

Images for Web pages fall into two general classes:

Inline images. External images.


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Inline images

Inline images appear on a Web page along with text and links, and are automatically loaded when the page itself is retrieved

External images External images are stored separate from the

Web page and are loaded only on demand, for example, as the result of a link.


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Note

Regardless of whether you're using inline or external images, those images must be in a specific format. For inline images, that image has to be in one of two formats:

GIF. JPEG.


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Inline Images in HTML: The <IMG> Tag

After you have an image in GIF or JPEG format ready to go, you can include it in your Web page.

Inline images are indicated in HTML using the <IMG> tag. The <IMG> tag,

Like the <HR> and <BR> tags, has no closing tag.


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Images and Text

To include images inside a line of text, just add the <IMG> tag at the appropriate point, inside an element tag (<H1>, <P>, <ADDRESS>, and so on):

<H1><IMG SRC="web.gif">The Halloween House of Terror!!</H1>


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Image Can Go Anywhere In Text

<BLOCKQUOTE>Love, from whom the world <IMG SRC="world.gif"> begun,<BR>Hath the secret of the sun. <IMG SRC="sun.gif"> <BR>Love can tell, and love alone,Whence the million stars <IMG SRC="star.gif"> were strewn <BR>Why each atom <IMG SRC="atom.gif"> knows its own. <BR></BLOCKQUOTE>


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Image Alignment

The <IMG> tag also includes an ALIGN attribute which allows you to align the image.


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Adjusting the Space Around Images

you may also want to adjust the amount of space around that image.

The VSPACE and HSPACE attributes allow you to do this. Both take a value in pixels;

VSPACE controls the space above and below the image.

HSPACE controls the space to the left and the right.

<P><IMG SRC="eggplant.gif" VSPACE=30 HSPACE=30 ALIGN=LEFT>


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Images and Links

Can an image serve as a link? Sure it can! If you include an <IMG> tag inside the

opening and closing parts of a link tag (<A>), that image serves as a clickable hot spot for the link itself:

<A HREF="index.html"><IMG SRC="uparrow.gif"></A>


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Using External Images

<A HREF="bigtomatos.jpeg">tomatos</A>


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Note

Images are not the only types of files you can store externally to your Web page. Sound files, video, zip archives-just about anything can be linked as an external file.


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Image Borders

Normally, plain images don't have borders; only images that hold links do.

But you can use the BORDER attribute with plain images to draw a border around the image, like this:

<P>Frame the image <IMG SRC="monalisa.gif" BORDER=5></P>



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Changing the Background Color

<BODY BGCOLOR=white> <BODY BGCOLOR=green>


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Changing Text Colors


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For example, to create a page with a black background, white text, and bright purple unfollowed links, you might use the following <BODY> tag:

<BODY BGCOLOR=black TEXT=white LINK=purple>


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Spot Color

When you change the text colors in a page using attributes to the <BODY> tag, that change affects all the text on the page.

Spot color is the ability to change the color of individual characters inside your page.

<FONT COLOR="#FF0000">RED</FONT>.


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Image Backgrounds <BODY BACKGROUND="tiles.gif">

<BODY BACKGROUND="backgrounds/rosemarble.gif" BGPROPERTIES=FIXED>


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Introducing Tables

In print publications, tables are a basic design element.

They're used to present data in rows and columns.

They make comparative analysis more understandable.


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The basic HTML table tags <TABLE></TABLE>--These HTML tags are the containers for

the rest of the table data.

<TR></TR>--Each row in the table is contained by these tags. You can optionally leave off the closing </TR> tag.

<TD></TD>--Defines a cell. Table data is contained within these tags. You can also nest additional tables within a single cell. You can optionally leave off the closing </TD> tag.

<TH></TH>--These table header tags are used to define headers, usually in the first row or column of the table. You can optionally leave off the closing </TH> tag.


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In addition to the basic tags

BORDER attribute--By using the BORDER attribute of the <TABLE> tag, borders are put around the table. You set the value of this attribute to the number of pixels wide you want the border, like this: BORDER=1.

If you set this attribute to 0, the browser will not display a border.

ALIGN attribute--The ALIGN attribute can be specified in the <TABLE> tag with possible values of LEFT, RIGHT, and CENTER (the default is LEFT).


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Example <TABLE BORDER>

<TR> <TH>Colors</TH><TH>Of</TH><TH>The Rainbow</TH> <TR> <TD>Red</TD><TD>Orange</TD><TD>Yellow</TD> </TR> <TR> <TD>Green</TD><TD>Blue</TD><TD>Violet</TD> </TR> </TABLE>


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Aligning Table Elements

<CAPTION> The ALIGN attribute can be specified for this element with possible values of TOP and BOTTOM (the default is TOP).

This places the table caption above or below the table.

<TR ALIGN=RIGHT>


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Understanding Empty Cells <TABLE > <TR><TD>Amaranth</TD><TD> </TD><TD>Buckwheat</TD></TR>

<TR><TD>Barley </TD><TD>Rye </TD><TD></TD></TR> <TR><TD>Quinoa </TD><TD>Wheat</TD><TD></TD></TR>

</TABLE>


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Controlling Table Layout WIDTH attribute--This enables you to specify the width of the table,

either in pixels or as a percentage of the width of the browser window. You can also use this attribute with individual cells.

HEIGHT attribute--This enables you to specify the height of the table, either in pixels or as a percentage of the height of the browser window. You can also use this attribute with individual cells.

BORDER attribute--This attribute puts a border around the table. You specify the width of the border in pixels, like this: BORDER=2.

CELLPADDING and CELLSPACING attributes--These numerical attributes include extra space within each cell in the table and/or within the borders of the table. If the border is not being displayed, they are equivalent.


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Using Color in Tables

Changing the entire table's color <TABLE BGCOLOR=WHITE>

Changing the entire Row color <TABLE > <TR BORDERCOLOR=BLACK BGCOLOR=WHITE>

Changing a single cell's color <TR><TD BORDERCOLOR=BLACK BGCOLOR=WHITE>1-one</TD


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New attributes which will be used in this programme

ROWSPAN COLSPAN (it is similar

to the rowspan but it covers columns instead of rows)

Here we have used rowspan=3rowspan=3 is because BEIT is covering 3 rowsCode:<td rowspan=3>BEIT1</td>


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Make a Page


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<HTML><BODY><TABLE align=center><Caption align=center>Main Table</caption><tr><td><table border=3 bordercolor=red align=center><Caption align=center>Main Table</caption><tr><th>Name</th><th>Class</th><th>Gpa</th><tr><td>Rizwan</td><td rowspan=3 align=center>BEIT1</td><td>3.3</td><tr><td>Ali</td><td>3.2</td><tr><td>Saqib</td><td>3.3</td></table></td><td><table border=3 bordercolor=green align=center><Caption align=center>Main Table</caption><tr><th>Name</th><th>Class</th><th>Gpa</th><tr><td>Rizwan</td><td rowspan=3 align=center>BEIT1</td><td>3.3</td><tr><td>Ali</td><td>3.3</td><tr><td>Saqib</td><td>3.3</td></table></td></tr></table></BODY></HTML>

CODE

FOR LAST

SLIDE


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C LanguageIntro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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Difference between low and high level languages

Low Level Languages

There are two types of low level language

a) Machine Lang

b) Assembly Lang


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Machine Language

The computer works only with 0 and 1.The arrangements of 0s and 1s is called a binary code.

We have to enter the instruction in the computer in the form of binary code.

Machine language is difficult to understand and learn.

The programme written on one type of computer cannot run on another type of computer system.


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Assembly Language

Assembly Language was developed to make programming task easier. In this machine instruction are represented by English words. These words are called mnemonics. Mnemonic is spelled as Ne.Monic.

Since english words are used in assembly Language, the Language programme are translated into machine Language. The application that translate an assembly Language program into the machine Language is called assembler.


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High Level Language The programming Language that are close to human Language

are called high level Language. The instruction in these Language are more like human Language.

BASIC, FORTRAN, COBOL, PASCAL , C, C++. These Language are easier to learn. These Languages are used for writing application programmes. Every high level Language has its own set of rules for writing

programes.These rules are called the syntax of the Language. High level Language can be implemented on any machine.


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Characteristics of High Level Language

Machine Independence. Can be implemented on variety of machines. Easier to understand. Well defined syntax. Easy to debug.


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Program 1#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c;

printf(“Enter the two numbers”);

scanf(“%d”, &a);

scanf(“%d”, &b);

c=a+b;

printf(“The result is :”, c);

}

Pre-processor Directives

This is a main function in any program.

int is Data type. Data type can be float, char, shortlong, unsigned

prinf is of printing any thing on screen

scanf is used for getting data from the keyboard.Data may be int (%d), float (%f) or char (%c)

We can enter formula in every program


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Range of Data Types

%d is used for integer data type%f is used for float data type and for double%c is used for char data type


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Operators Precedence

All Multiplication and Division are performed first from left to right. All addition and subtraction are then performed from left to right. If parentheses are used in an expression , the expression within the

parentheses are first computed from left to right. When parentheses are used within parenthesis , the expression within

the innermost parenthesis is evaluated first.

For Example

(4-(3*5))+2

1) (3*5) is computed and returns value of 15

2) 4-15 is computed and returns value of -11

3) -11+2 is computed and returns value of -9


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Operator Description Associativity

()[].->

++ --

Parentheses (function call) (see Note 1)Brackets (array subscript)

Member selection via object nameMember selection via pointer

Postfix increment/decrement (see Note 2)

left-to-right

++ --+ -! ~

(type)*&

sizeof

Prefix increment/decrementUnary plus/minus

Logical negation/bitwise complement

Cast (change type)Dereference

AddressDetermine size in bytes

right-to-left

* / % Multiplication/division/modulus left-to-right

+ - Addition/subtraction left-to-right

<< >> Bitwise shift left, Bitwise shift right left-to-right

< <=> >=

Relational less than/less than or equal toRelational greater than/greater

than or equal to

left-to-right

C Operator Precedence Chart


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== != Relational is equal to/is not equal to left-to-right

& Bitwise AND left-to-right

^ Bitwise exclusive OR left-to-right

| Bitwise inclusive OR left-to-right

&& Logical AND left-to-right

|| Logical OR left-to-right

?: Ternary conditional right-to-left

=+= -=*= /=%= &=^= |=

<<= >>=

AssignmentAddition/subtraction assignment

Multiplication/division assignmentModulus/bitwise AND assignment

Bitwise exclusive/inclusive OR assignmentBitwise shift left/right assignment

right-to-left

, Comma (separate expressions) left-to-right


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Write programme to compute area of a triangle. The formula for the area of triangle is

Area=√ (s(s-a)(s-b)(s-c)where s=a+b+c/2

Program 2


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#include<stdio.h>#include<conio.h>#include<math.h>void main(){int a,b,c;double area, s; a=190;b=200;c=300;s=a+b+c/2.0;area= sqrt(s*(s-a)*(s-b)*(s-c));printf(“Calculated Area = %f ”, area);}


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Write a programme to compute the distance covered by a car in 50 sec.The initial velocity is 10m/sec and acceleration is 5m/sec².Use the formula

s= vit +1/2at²

Program 3


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#include<stdio.h>

void main()

{

int t, vi, a ;

double s;

t=50;

vi=10;

a=5;

s=a+b+c/2.0;

s= vi*t+0.5*a*t*t ;

printf(‘’Distance covered = %f ”, s);

}


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Write a program to input a number. Calculate the cube of the number and print the result on the screen

Program 4


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#include<stdio.h>

void main()

{

int n, res ;

printf(‘’Enter any number ?”);

scanf(“%d” , &n);

res= n*n*n;

printf(‘’ The cube of %d is = %d” ,n, res);

}


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Program 5

Write a programme to input the marksobtained by a student in threesubjects. Calculate the total marks and their average and print the results on the screen.


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#include<stdio.h>

void main()

{

float Math, Urdu, Islamiat, Total, Avg;

printf (“ Enter marks of Maths”);

scanf(“ %f ” , Math);

printf (“ Enter marks of Urdu”);

scanf(“ %f ” , Urdu);

printf (“ Enter marks of Islamiat”);

scanf(“ %f ” , Islamiat);

Total= Math+Urdu+Islamiat;

Avg= Total/3;

printf(“The Total marks are= %f ”, Total);

printf(“The Average marks are= %f ”, Avg);

}


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Conditional StatementsIntro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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If ConditionIntro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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#include<stdio.h>#include<math.h>#include<conio.h>

void main(){double x , sqr;clrscr();printf(“Enter the Number”);scanf(“%1f ”,&x);if(x>0) {sqr=sqrt(x);printf(“Square root is %1f ”,sqr);getche();}}


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If Else ConditionIntro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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#include<stdio.h>#include<math.h>#include<conio.h>

void main(){double x , sqr;clrscr();printf(“Enter the Number”);scanf(“%1f ”,&x);if(x>=0) {sqr=sqrt(x);printf(“Square root is %1f ”,sqr);getche();}elseprintf(“Square root can not be computed”);} Intro to IT by Rizwan GhoriIntro to IT by Rizwan Ghori

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#include<stdio.h>#include<conio.h>#include<conio.h>

void main(){int a,b;clrscr();printf(“Enter the 1st Number”);scanf(“%d”,&a);printf(“Enter the 2nd Number”);scanf(“%d”,&b);if(a>b)printf(“First Number is greater”);elseprintf(“Second Number is greater”);}


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#include<stdio.h>#include<conio.h>void main(){int a;printf(“Enter the Number”);scanf(“%d”,&n);if(n%2==1)printf(“It is an odd number”);elseprintf(“It is an even number”);}


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else if


04/07/23

#include<stdio.h>#include<conio.h>void main(){int a=0,b=0;char op;clrscr();

printf(“Enter 1st integer, operator, 2nd integer”);scanf(“%d %c %d”,&a,&op,&b);if( op==‘+’){printf(“Addition= %d”, a+b);getche();}else if( op==‘-’){printf(“Sub= %d”, a-b);getche();}else if( op==‘*’){printf(“Mul = %d”, a*b);getche();}else printf(“Not valid input”);}


04/07/23

Switch


04/07/23

#include<stdio.h>#include<conio.h>void main(){char ch;

printf(“Enter an Alphabet ”);ch=getche();switch(ch){case ‘a’:case ‘A’:printf(“It is a vowel ”);break;case ‘e’:case ‘E’:printf(“It is a vowel ”);break;case ‘i’:case ‘I’:printf(“It is a vowel ”);break;case ‘o’:case ‘O’:printf(“It is a vowel ”);break;case ‘u’:case ‘U’:printf(“It is a vowel ”);break;Default:Printf(“you entered a consonant”);}}


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