Computer Fundamental

1. Introduction to Computers

Image of Computer

A computer is a device that can receive, process and store data. They are used as tools in every part of society together with the Internet. Computers nowadays are complex; there are a lot of different components inside them, and they all serve different purposes. They all need to work together for the computer to work; knowing how a computer works makes it easier to use a computer by being able to understand how a computer will respond.

A computer is an electronic device that takes input such as numbers, text, sound, image, animations, video, etc., processes it, and converts it into meaningful information that could be understood, presenting the changed input (processed input) as output. All numbers, text, sound, images, animations, and video used as input are called data, and all numbers, text, sound, images, animations, and video returned as output are called information.

i. The data consists of numbers, text, sound, images, animations, and video.

ii. The process converts numbers, text, sound, images, animations, and video (data) into usable data, which is called information.

iii. The information consists of numbers, text, sound, images, animations, and video that has been converted by the process.

iv. The data is inserted using an input device.

v. The central processing unit (CPU) converts data to information.

vi. The information is put on an output device.

2. Who is the inventor of the computer?

Charles Babbage, FRS (/ˈbæbɪdʒ/; 26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage is best remembered for originating the concept of a programmable computer.

3. What the computer can do?

Many modern computers do billions of calculations each second. Theydo mathematical arithmetic very quickly but computers do not really "think". They only follow the instructions in their software programs.Computer programs are designed or written by computer programmers.

4. Full Name of Computer.

C = Commonly

O = Operating

M = Machine

P = Particularly

U = Used for

T = Trade

E = Education and

R = Research

5. Advantages of Computers

Characteristics of computers

Computers of all sizes have common characteristics - speed, arithmetical and logical operations, accuracy, reliability, storage, retrieving data and programs, automation, versatility, communications, diligence, feelings, consistency and precision. Computers are the foundation of business, travel, and leisure life today. Computers provide the processing speed required by all facets of society. The quick service we expect at the bank, at the grocery store, on the stock exchange, and on the Internet are dependent on the speed of computers. Can you imagine our world without computers?

Computers are extremely reliable as well. Most errors are caused by humans, not computers. Computers are capable of storing enormous amounts of data that must be located and retrieved very quickly. The capability to store and retrieve volumes of data is at the core of the Information Age. Now-a-days computer is playing a main role in everyday life it has become the need of people just like television, telephone or other electronic devices at home. It solves the human problems very quickly as well as accurately. The important characteristics of a computer are described below:

Speed

The computer is a very high speed electronic device. The operations on the data inside the computer are performed through electronic circuits according to the given instructions. The data and instructions flow along these circuits with high speed that is close to the speed of light. Computer can perform millions of billions of operations on the data in one second. The computer generates signals during the operation process therefore the speed of computer is usually measure in megahertz (MHz) or Giga hertz (GHz). It means million cycles units of frequency is hertz per second. Different computers have different speed.

Arithmetical and Logical Operations

A computer can perform arithmetical and logical operations. In arithmetic operations, it performs the addition, subtraction, multiplication and division on the numeric data. In logical operation it compares the numerical data as

well as alphabetical data.

Accuracy

In addition to being very fast, computer is also very accurate device. It gives accurate output result provided that the correct input data and set of instructions are given to the computer. It means that output is totally depended on the given instructions and input data. If input data is in-correct then the resulting output will be in-correct. In computer terminology it is known as garbage-in garbage-out.

Reliability

The electronic components in modern computer have very low failure rate. The modern computer can perform very complicated calculations without creating any problem and produces consistent (reliable) results. In general, computers are very reliable. Many personal computers have never needed a service call. Communications are also very reliable and generally available whenever needed.

Storage

A computer has internal storage (memory) as well as external or secondary storage. In secondary storage, a large amount of data and programs (set of instructions) can be stored for future use. The stored data and programs are available any time for processing. Similarly information downloaded from the internet can be saved on the storage media.

Retrieving data and programs

The data and program stored on the storage media can be retrieved very quickly for further processing. It is also very important feature of a computer.

Automation

A computer can automatically perform operations without interfering the user during the operations. It controls automatically different devices attached with the computer. It executes automatically the program instructions one by one.

Versatility

Versatile means flexible. Modern computer can perform different kind of tasks one by one of simultaneously. It is the most important feature of computer. At one moment you are playing game on computer, the next moment you are composing and sending emails etc. In colleges and universities computers are used to deliver lectures to the students. The talent of computer is dependent on the software.

Communications

Today computer is mostly used to exchange messages or data through computer networks all over the world. For example the information can be received or send through the internet with the help of computer. It is most important feature of the modern information technology.

Diligence

A computer can continually work for hours without creating any error. It does not get tired while working after hours of work it performs the operations with the same accuracy as well as speed as the first one.

Feelings

Computer is an electronic machine. It has no feelings. It detects objects on the basis of instructions given to it. Based on our feelings, taste, knowledge and experience: we can make certain decisions and judgments in our daily life. On the other hand, computer cannot make such judgments on their own. Their judgments are totally based on instructions given to them.

Consistency

People often have difficulty to repeat their instructions again and again. For example, a lecturer feels difficulty to repeat a same lecture in a class room again and again. Computer can repeat actions consistently (again and again) without losing its concentration:

To run a spell checker (built into a word processor) for checking spellings in a document.
To play multimedia animations for training purposes.
To deliver a lecture through computer in a class room etc.
A computer will carry out the activity with the same way every time.
You can listen a lecture or perform any action again and again.

Precision

Computers are not only fast and consistent but they also perform operations very accurately and precisely. For example, in manual calculations and rounding fractional values (That is value with decimal point can change the actual result). In computer however, you can keep the accuracy and precision up to the level, you desire. The length calculations remain always accurate.

Others Advantage of Computer you can write or read.

Speed Up Work Efficiency

This is by far the biggest advantage of using computers. They have replaced the use of manpower in carrying out tedious and repetitive work. Work that can take days to complete manually can be done in a few minutes using a computer. This is made possible by the fact that data, instructions and information move very fast in the electric circuits of computers. They process trillions of instructions within a second.

Large and Reliable Storage Capacity

Computers can store huge volumes of data. To put this into perspective, physical files that can fill a whole room can be stored in one computer once they are digitized. Better yet, access to the stored information is super-fast. It takes micro-seconds for data to be transferred from storage to memory in a computer. The same cannot be said for the retrieval of physical files. With a computer, you can store videos, games, applications, documents etc. that you can access whenever required. Better yet, storage can be backed up fast and efficiently.

Connection with Internet

The Internet is probably the most outstanding invention in history. Computers allow you to connect to the Internet and access this global repository of knowledge. With the Internet, you can communicate faster with people across the globe. You can send email, hold voice and video calls or use IM services. The Internet also allows for instant sharing of files. You can also connect with friends and family on social networks and even learn a new language online. The Internet is a great educational resource where you can find information on virtually anything.

One of the biggest breakthroughs on the Internet is probably ecommerce. You can actually shop in the convenience of your home and have the items delivered to your doorstep.

Consistency

You always get the same result for the same process when using a computer. For example if you created a document on one computer, you can open it on another without making any special adjustments. This consistency makes it possible to save and edit a document from different computers in different parts of the world. Collaboration is therefore easier.

Whatever job you need done, you can always rest assured that the computer will get it just right. There will be no variations in results achieved from the same process. This makes computers ideal for doing tedious and repetitive work.

Disadvantages of Computers

Health Risk

Improper and prolonged use of a computer might lead to disorders or injuries of the elbows, wrist, neck, back, and eyes. As a computer user you can avoid these injuries by working in a workplace that is well designed, using a good sitting position and taking proper work breaks. Technology load and computer addiction are the major behavioral health risks. Addiction comes when you are obsessed with a computer. Technology overload comes when you are over loaded with computer and mobile phones. Both technology overload and computer addiction are avoidable if the habits are noted and a follow up is done.

Violation of Privacy

When using the Internet on your computer, you run the risk of leaking your private information. This is especially so if you happen to download malicious software into your computer. Trojans and Malware can infiltrate your system and give identity thieves access to your personal information. Of particular interest to identity thieves are your bank and credit card details. Make sure to install reliable antivirus software to keep malware and Trojans at bay. You should also avoid clicking on suspicious looking links when using the Internet.

Impact on Environment

Manufacturing process of computers and computer waste are harmful to the environment. When computer junk is discarded in open grounds, they release harmful chemicals like lead and mercury to the environment. Mercury can result in cancer and lead can cause radiation diseases when exposed to the environment. Disposed computers could also cause fire.

Data Security

This is one of the most controversial aspects of computers today. The safety and integrity of data is key for any business. However, data stored in a computer can be lost or compromised in a number of ways. There are instances where the computer could crash wiping out all data that had been stored therein. Hackers could also gain access into your computer and compromise the integrity of your data. This is why you should always have a backup. Moreover, you should put measures in place to keep your data safe from hackers.

Unemployment

Different tasks are performed automatically by using computers. It reduces the need of people and increases unemployment in society.

Wastage of time and energy

Many people use computers without positive purpose. They play games and chat for a long period of time. It causes wastage of time and energy. Young generation is now spending more time on the social media websites like Facebook, Twitter etc or texting their friends all night through smartphones which is bad for both studies and their health. And it also has adverse effects on the social life.

Data Security

The data stored on a computer can be accessed by unauthorized persons through networks. It has created serious problems for the data security.

Computer Crimes

People use the computer for negative activities. They hack the credit card numbers of the people and misuse them or they can steal important data from big organizations.

Privacy violation

The computers are used to store personal data of the people. The privacy of a person can be violated if the personal and confidential records are not protected properly.

Health risks

The improper and prolonged use of computer can results in injuries or disorders of hands, wrists, elbows, eyes, necks and back. The users can avoid health risks by using the computer in proper position. They must also take regular breaks while using the computer for longer period of time. It is recommended to take a couple of minutes break after 30 minutes of computer usage.

Impact on Environment

The computer manufacturing processes and computer waste are polluting the environment. The wasted parts of computer can release dangerous toxic materials. Green computer is a method to reduce the electricity consumed and environmental waste generated when using a computer. It includes recycling and regulating manufacturing processes. The used computers must be donated or disposed off properly.

5. Software

Software can be divided into two groups, system and application.

System software - The operation of your computer is controlled by system software. As you boot the computer, the system software is stored in the computer's memory which instructs the computer to load, store, and execute an application.

Examples of system software are Windows 95 and Windows 98 which use a graphical user interface (GUI) that provides visual clues (icons) to help the user. DOS, another disk operating system, is text based and not user friendly.

Professional programmers write a variety of application software to satisfy needs of the public who wants to perform specific tasks on their computers. The basic types of application software are word processing, database, spreadsheet, desktop publishing, and communication.

Word Processing - Word processing is the most commonly used software in schools, home, and business. A key advantage of word processing software is that users can make changes such as spelling, margins, additions, deletions, and movement of text. A beginning computer student should learn word processing, as it is the basis of most software. Once you have learned how a word processor functions, you will be able to learn other software quicker.
Database Software - Database software allows us to store and manipulate large quantities of data using the computer. For example, a database can sort the names, addresses, grades and activities for all of the students in a school. It would be possible to add or delete data and produce printed reports using the database.
Spreadsheet Software - Spreadsheets store numeric data that can be used in calculations. A spreadsheet is used to store a teachers grades and then calculate student averages. The primary advantage of a computerized spreadsheet is its ability to redo the calculations should the data it stores be changed. Calculations can be made automatically as formulas have been preset into the spreadsheet.
Desktop Publishing - Desktop publishing applications allow the user to create newspapers, newsletters, brochures, and similar types of publications. It is similar to word processing except it allows the user to use text, graphics, pictures, lines, shapes, patterns, and borders. Desktop publishing requires more skill and computer knowledge of design and layout.

Presently a user can purchase an integrated program. This means that a single program performs all applications and allows data to be transferred from one application to another. Microsoft Office 97, Works, and ClarisWorks are examples of integrated software. Each application includes a word processing, data base and spreadsheet section of the software.

There are numerous other applications available. There are software programs that can be used by musicians to produce musical scores and play them on a synthesizer, programs that assist an architect in designing a building, programs that produce the special effects that you see in movies, and programs that allow e-mail or electronic mail. Every line of work you can think of has had applications developed, which can ease or enhance its effectiveness and consistency.

6. Hardware

Computer hardware is made up of the equipment used to make up you computer unit. These parts include your monitor, central processing unit (CPU), keyboard, mouse, printer, and modem.

The computer is an electronic machine that performs the following four general operations:

Input
Storage
Processing
Output.

Input

The input hardware allows you to enter data into the computer. The primary devices used are the keyboard and mouse.

Keyboard - The keyboard looks like the typewriter. A numeric keypad is located to the right of the keyboard. Numeric keys have the same placement as a 10-key calculator, which allow the operator to enter data rapidly.

Mouse - The mouse is a device that allows you to control the movement of the insertion point on the screen. The operator places the palm of the hand over the mouse and moves it across a mouse pad, which provides traction for the rolling ball inside the device. Movement of the ball determines the location of the I beam on the computer screen. When the operator clicks the mouse the I beam becomes an insertion point which indicates the area you are working on the screen. You can also click the mouse and activate icons or drag to move objects and select text.

Light Pen-This is also categorized into a pointing device, which can be used only with video displays. It can be used to select an option by simply pointing at it, or drawing figures directly on the screen. An electron beam that repeatedly scans the display screen from left to right and from top to bottom produce a video display. Because of this scanning action, each point on the display is illuminated at a slightly different time. The light pen, which is a pen like device, has a photo detector at its tip. The detector can detect changes in the brightness of the screen. The light pen is connected to the computer by a cable. When the pen is pointed at a particular spot on the screen, the point is scanned and the photo detector records changes in the brightness and sends electrical pulses to the computer. The computer can find out the exact spot with this information. Light pens are useful for menu-based applications. It is also useful for drawing graphics in Computer Aided Design software.

Touch Screen- 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.

Joy Stick: A lever that moves in all directions and controls the movement of a pointer or some other display symbol. 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, but they are also used occasionally for CAD/CAM systems and other applications.

Scanners- These are the eyes of your computer. They can see images or printed text and translate them into binary code. Most scanners collect data from a page by recording, which areas are light and which areas are dark. They contain a camera, which is made up of thousands of tiny cells, called charge coupled devices (CCD). Each CCD detects whether a small part of the image is either light or dark. It transmits this data to the CPU, which then creates the image. Some scanners are sensitive enough to tell the difference between colors. Many scanners available nowadays are capable of not only scanning texts and graphics, but also integrated text and graphic files. Scanners are used to reproduce photographs on the computer screen. Businesses use scanners for storing documents on the computer.

Optical Character Readers (OCR)- These are another kind of input devices that are used to read any printed text. They can interpret handmade marks, handwritten characters, machine printed characters and special symbols and codes. Optical character readers scan text character-by-character converts them into machine readable codes and store it in the memory. Since they read characters at the rate of around 2600 characters per second this reduces the organizations the data inputting time.

Magnetic Ink Character Reader (MICR)- A magnetic character reader system for reading and identifying magnetized characters printed on a document such as a check, in which analog wave forms derived from scanning the characters are analyzed by rectifying and integrating the waveform to generate a value representing the gain of a programmable gain amplifier for use in amplifying the waveform to compensate for variations in ink intensity. Means are provided for generating a value representing the center of gravity of the area under each peak of the amplified waveform for use in re-timing the peak sampling windows for compensating for variations in the speed of the document past the magnetic read head. Digital values representing the area under each peak curve in the waveform are compared with corresponding values of a plurality of reference characters to identify the unknown character.

Bar Code Reader- This is used to read different kind of vertical lines known as bars which signify some information.

Touch Pad- Most laptop computers today have a touch pad pointing device. You move the on-screen cursor by sliding your finger along the surface of the touch pad. The buttons are located below the pad, but most touch pads allow you to perform “mouse clicks” by tapping on the pad itself. Touch pads have the advantage over mouse that they take up much less room to use. They have the advantage over trackballs (which were used on early laptops) that there are no moving parts to get dirty and result in jumpy cursor control.

Track Point- Some sub-notebook computers (such as the IBM Think Pad), which lack room for even a touch pad, incorporate a track point, a small rubber projection embedded between the keys of the keyboard. The track point acts like a little joystick that can be used to control the position of the on-screen cursor. graphics tablet consists of an electronic writing area and a special “pen” that works with it. Graphics tablets allow artists to create graphical images with motions and actions similar to using more traditional drawing tools. The pen of the graphics tablet is pressure sensitive, so pressing harder or softer can result in brush strokes of different width (in an appropriate graphics program).

Microphone- A microphone can be attached to a computer to record sound (usually through a sound card input or circuitry built into the motherboard). The sound is digitized – turned into numbers that represent the original analog sound waves – and stored in the computer to later processing and playback.

Processing

The central processing unit or (CPU) is the "brain" of your computer. It contains the electronic circuits that cause the computer to follow instructions from ROM (read only memory) or from a program in RAM (random access memory). By following these instructions information is processed. The CPU contains three parts.

Arithmetic Logic Unit - ALU is where the "intelligence" of the computer is located. It can add and compare numbers. To multiply 2 x 4 the computer would add 2 + 2 + 2 + 2. The ALU makes decisions by determining if a number is greater, less, or equal to the other number. Processing is completed in nanoseconds, which is a billionth of a second.
Memory - Two types of memory contained on a chip are RAM (Random Access Memory) or ROM (Read Only Memory). ROM memory has been installed on your computer by the manufacturer and can not be altered. ROM is the memory that determines all the basic functions of the operation of your machine, such as startup, shut down, and placing a character on the screen. RAM is temporary memory, which displays the information you are working on. RAM remembers what you see on your screen while you are working. Today's applications required large amounts of temporary memory, which may require you to upgrade and add more RAM memory.
Control Unit - This is the part of the unit, which directs information to the proper places in your computer, such as calculation of information by the ALU unit or to store and print material.

Output

Output devices such as a monitor or printer make information you input available for you to view or use.

A monitor's front is called a screen with a cathode ray tube (CRT) attached to the screen. Portable computers use a (LCD) liquid crystal display. Today's super video graphics array (SVGA) monitors display 256 sharp and clear colors.

Printers used with computers fall into two categories, impact or nonimpact. Impact printers, such as dot matrix print by contact against a ribbon making imprint on paper. Inkjet printers print images by not touching the paper. Ink jet printers spray ink onto the page while a laser printer works like a copying machine. Laser printers print a higher quality product but cost from $500 to $10,000 whereas an ink jet produces better quality than a dot matrix and can be purchased from $150 to $300. The personal computer user most commonly purchases an ink jet printer for home use.

Storage

Auxiliary storage devices, also called secondary storage devices, are used to store instructions and data when they are not being used in memory. Two types of auxiliary storage more often used on personal computers are floppy disks and hard disks. Also, CD-ROM drives are common.

Floppy Disks - A floppy disk is a circular piece of oxide-coated plastic that stores data as magnetic spots. Personal computers most commonly use floppy disks that are 3 inches in diameter. To read data stored one floppy disk or to store data on a floppy disk, you insert the floppy disk in a disk drive. If the disk is unused, you must format or initialize it before your computer will allow you to store data on it. Formatting organizes the tracks around the disk into pie like slices called sectors which make it possible for your computer to save and retrieve information. The density of the bits on the track and number of tracks on a disk determine the number of characters that can be stored. Floppy disks are identified as being double density or high density. Most machines purchased after 1993 will use a high-density disk. A machine that has a double density drive can't process a high-density disk. Note the chart below for disk information.

Floppy disks must be handled with care to preserve data. Follow the suggestions to protect your floppy disk.

Store in box or disk storage container.

Protect disk from dust.

Keep disk out of sunlight and away from extremes of hot or cold.

Don't press hard when writing on labels. Use a felt tip pen.

Insert metal side into drive first with the hub of the disk down.

Don't store disk near magnetic sources.

Hard Drive - Much like a floppy, the hard disk located inside the computer case is made of a stack of rotating disks, called platters. Data is recorded on a series of tracks that have been divided into sectors. Most computers have one hard drive, located inside the computer case. If a computer has one hard drive, it is called drive C. If a computer has additional hard drives, they are called drives D, E, and so on. A hard drive stores your programs. When you buy a new program, you must install the program files to your hard drive before you can use the program. A hard drive stores your data files such as documents spreadsheets, and graphics.

CD-ROM Storage - Since each CD-ROM can store 600 million bytes of data or 300,000 pages of text, they are today's answer to make you computer feel like a machine twice its size. Because of its external storage, you can use your machine to access an encyclopedia, games, graphics, and a variety of sources that use large amounts of memory.

A computer stores data in units called bits and bytes. Computer chips called integrated circuits have one of two states, off or on. Therefore, a system was developed that used only two numbers, 0 and 1. Zero representing off and 1 representing on. You can think of this as a sort of light switch. Each switch is called a bit.

Bits are grouped together in sets of eight. Each set of eight bits is called a byte. Setting different combinations of those eight "on and off" combinations can be developed to stand for letters numbers, spaces, and symbols. For practical purposes, think of a byte as one character. When computers refer to memory or storage they refer to terms using the following forms of measurement.

7. Central Processing Unit:

The central processing unit (CPU) is the electronic brain of the computer. The CPU in a personal computer is usually a single chip. It organizes and carries out instructions that come from either the user or from the software. The processor is made up of many components, but two of them are worth mentioning at this point. These are the arithmetic and logic unit and the control unit. The control unit controls the electronic flow of information around the computer. The arithmetic logic unit, ALU, is responsible for mathematical calculations and logical comparisons. The processor is plugged into the computer’s motherboard. The motherboard is a rigid rectangular card containing the circuitry that connects the processor and all the other components that make up your personal computer. In most personal computers, some of the components are attached directly to the motherboard and some are housed on their own small circuit boards that plug into the expansion slots built into the motherboard.

The processing capacity of a computer is measured in terms the amount of

data processed by the CPU in one operation. The CPU has three important

sub units.

Arithmetic-Logic unit
Control Unit
Memory Unit

Arithmetic-Logic Unit (ALU): The ALU is an electronic circuit used to carry out the arithmetic operations like addition, subtraction, multiplication and division. This unit carries out logical operations like greater than, less than, equal to etc. It performs the operation on the data provided by the input devices. A comparison operation allows a program to make decisions based on its data input and results of the previous calculations. Logical operations can be used to determine whether particular statement is TRUE or FALSE. The ALU operates on the data available in the main memory and sends them back after processing again to main memory.

Control Unit: The control unit coordinates the activities of all the other units in the system. Its main functions are to control the transfer of data and information between various units and to initiate appropriate actions by the arithmetic-logic unit. Conceptually, the control unit fetches instructions from the memory, decodes them, and directs them to various units to perform the specified tasks.

Memory Unit: The main memory is also called primary memory, is used to store data temporarily. Although, the CPU is the brain behind all the operations in the computer, it needs to be supplied with the data to be processed and the instructions to tell it what to do. Once the CPU has carried out an instruction, it needs the result to be stored. This storage space is provided by the computer’s memory. Data provided by the input device, and the result of that processed data is also stored in the memory nit. This main memory is like a scratch pad. The storage capacity of the memory is generally measured in megabytes.

8 Bits = 1 Byte
1024 Bytes = 1 Kilobyte (KB)
Fundamentals of Computer and IT Unit 1
Sikkim Manipal University Page No. 20
1024 Kilobytes = 1 Megabyte (MB)
1024 Megabytes = 1 Gigabyte (GB)

Different kinds of primary memory are Random Access Memory (RAM) and Read Only Memory (ROM). You can read and write data in RAM but the data is volatile or temporary that is whenever the power is switched off the contents of RAM is lost so it is required to store the data in the secondary memory if the data is required for the future use. But you can only read the data from ROM and you cannot write anything into it and the data is permanent. The manufacturer himself has written the data in it initially.

Secondary Memory

This is the permanent memory. The data stored in it is permanent. But you can delete the data if you want. There are different kinds of secondary storage devices available. Few of them are Floppy disks, Fixed (hard) disks and Optical disks etc.

8. Generation of Computer

The history of computer development is frequently stated to in reference to the different generations of computing devices. A generation refers to the state of improvement in the product development process. This term is also used in the different advancements of new computer technology. With each new generation, the circuitry has gotten smaller and more advanced than the previous generation before it. As a result of the diminishment, speed, power, and computer memory has proportionally increased. Newdiscoveries are constantly being developed that affect the way we live, work and play. Every generation of computers is considered by major technological development that fundamentally changed the way computers operate,resulting in increasingly smaller, cheaper, and more powerful and more efficient and reliable devices.

First Generation (1940-1956): Vacuum Tubes

The first generation computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. A magnetic drum, also referred to as drum, is a metal cylinder coated with magnetic iron-oxide material on which data and programs can be stored. Magnetic drums were once used as a primary storage device but have since been implemented as auxiliary storage devices.

The tracks on a magnetic drum are assigned to channels located around the circumference of the drum, forming adjacent circular bands that wind around the drum. A single drum can have up to 200 tracks. As the drum rotates at a speed of up to 3,000 rpm, the device's read/write heads deposit magnetized spots on the drum during the write operation and sense these spots during a read operation. This action is similar to that of a magnetic tape or disk drive. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions. First generation computers relied on machine language to perform operations, and they could only solve one problem at a time. Machine languages are the only languages understood by computers. While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers. Computer Programmers, therefore, use either high level programming languages or an assembly language programming. An assembly language contains the same instructions as a machine language, but the instructions and variables have names instead of being just numbers.

Packages written in high level programming languages retranslated into assembly language or machine language by a compiler. Assembly language

program retranslated into machine language by a program called an assembler (assembly language compiler). Every CPU has its own unique machine language. Programs must be rewritten or recompiled, therefore, to run on different types of computers. Input was based on punch card and paper tapes, and output was displayed on printouts. The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951. Acronym for Electronic Numerical Integrator and Computer, the world's first operational electronic digital computer, developed by Army Ordnance to compute World War II ballistic firing tables. The ENIAC, weighing 30 tons, using 200 kilowatts of electric power and consisting of 18,000 vacuum tubes, 1,500 relays, and hundreds of thousands of resistors, capacitors, and inductors, was completed in 1945. In addition to ballistics, the ENIAC's field of application included weather prediction, atomic-energy calculations, cosmic-ray studies, thermal ignition, random-number studies, wind-tunnel design, and other scientific uses. The ENIAC soon became obsolete as the need arose for faster computing speeds.

Second Generation (1956-1963): Transistors

Transistors replaced vacuum tubes and ushered in the second generation computer. Transistor is a device composed of semiconductor material that amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become the key ingredient of all digital circuits, including computers. Today's latest microprocessor contains tens of millions of

microscopic transistors.

Prior to the invention of transistors, digital circuits were composed of vacuum tubes, which had many disadvantages. They were much larger, required more energy, dissipated more heat, and were more prone to failures. It's safe to say that without the invention of transistors, computing as we know it today would not be possible.

The transistor was invented in 1947 but did not see widespread use in computers until the late 50s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second generation computers still relied on punched cards for input and printouts for output.

Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology. The first computers of this generation were developed for the atomic energy industry.

Third Generation (1965-1971): Integrated Circuits

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

A non-metallic chemical element in the carbon family of elements. Silicon – atomic symbol "Si" – is the second most abundant element in the earth's crust, surpassed only by oxygen. Silicon does not happen uncombined in nature. Sand and almost all rocks contain silicon combined with oxygen, forming silica. When silicon combines with other elements, such as iron, aluminum or potassium, a silicate is formed. Compounds of silicon also occur in the atmosphere, natural waters, and many plants and in the bodies of some animals.

Silicon is the basic material used to make computer chips, transistors, silicon diodes and other electronic circuits and switching devices because its atomic structure makes the element an ideal semiconductor. Silicon is commonly doped, or mixed, with other elements, such as boron, phosphorous and arsenic, to alter its conductive properties.

A chip is a small piece of semi conducting material (usually silicon) on which an integrated circuit is embedded. A typical chip is less than ¼-square inches and can contain millions of electronic components (transistors). Computers consist of many chips placed on electronic boards called printed circuit boards. There are different types of chips. For example, CPU chips (also called microprocessors) contain an entire processing unit, whereas memory chips contain blank memory. Semiconductor is a material that is neither a good conductor of electricity(like copper) nor a good insulator (like rubber). The most common semiconductor materials are silicon and germanium. These materials are then doped to create an excess or lack of electrons. Computer chips, both for CPU and memory, are composed of semiconductor materials. Semiconductors make it possible to miniaturize electronic components, such as transistors. Not only does miniaturization mean that the components take up less space, it also means that they are faster and require less energy.

Fourth Generation (1971- Present): Microprocessors

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits we rebuilt onto a single silicon chip and this will contains a Central Processing Unit. In the world of personal computers, the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor. Microprocessors also control the logic of almost all digital devices, from clock radios to fuel-injection systems for automobiles.

Three basic characteristics differentiate microprocessors:

Instruction Set: The set of instructions that the microprocessor can execute.
Bandwidth: The number of bits processed in a single instruction.
Clock Speed: Given in megahertz (MHz), the clock speed determines how many instructions per second the processor can execute.

Fifth Generation Computer

Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. Artificial Intelligence is the branch of computer science concerned with making computers behave like humans. The term was coined in 1956 by John McCarthy at the Massachusetts Institute of Technology. Artificial intelligence includes the following:

Games playing: Programming computers to play games such as chess and checkers.
Expert Systems: Programming computers to make decisions in real-life situations (for example, some expert systems help doctors diagnose diseases based on symptoms).
Natural Language: Programming computers to understand natural human languages.
Neural Networks: Systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains.
Robotics: Programming computers to see and hear and react to other sensory stimuli. Currently, no computers exhibit full artificial intelligence (that is, are able to simulate human behavior). The greatest advances have occurred in the field of games playing. The best computer chess programs are now capable of beating humans. In May,1997, an IBM super-computer called Deep Blue defeated world chess champion Gary Kasparov in a chess match. In the area of robotics, computers are now widely used in assembly plants, but they are capable only of very limited tasks. Robots have great difficulty identifying objects based on appearance or feel, and they still move and handle objects clumsily. Natural-language processing offers the greatest potential rewards because it would allow people to interact with computers without needing any specialized knowledge. You could simply walk up to a computer and talk to it. Unfortunately, programming computers to understand natural languages has proved to be more difficult than originally thought. Some rudimentary translation systems that translate from one human language to another are in existence, but they are not nearly as good as human translators.

There are also voice recognition systems that can convert spoken sounds into written words, but they do not understand what they are writing; they simply take dictation. Even these systems are quite limited – you must speak slowly and distinctly.

Voice Recognition: In the field of computer science that deals with designing computer systems that can recognize spoken words. Note that voice recognition implies only that the computer can take dictation, not that it understands what is being said. Comprehending human languages falls under a different field of computer science called natural language processing. A number of voice recognition systems are available on the market. The most powerful can recognize thousands of words. However, they generally require an extended training session during which the computer system becomes accustomed to a particular voice and accent. Such systems are said to be speaker dependent. Many systems also require that the speaker speak slowly and distinctly and separate each word with a short pause. These systems are called discrete speech systems. Recently, great strides have been made in continuous speech systems voice recognition systems that allow you to speak naturally. There are now several continuous-speech systems available for personal computers. Because of their limitations and high cost, voice recognition systems have traditionally been used only in a few specialized situations.

For example, such systems are useful in instances when the user is unable to use a keyboard to enter data because his or her hands are occupied or disabled. Instead of typing commands, the user can simply speak into a headset. Increasingly, however, as the cost decreases and performance improves, speech recognition systems are entering the mainstream and are being used as an alternative to keyboards. The use of parallel processing and superconductors is helping to make artificial intelligence a reality.Parallel processing is the simultaneous use of more than one CPU to execute a program. Ideally, parallel processing makes a program run faster because there are more engines (CPUs) are running. In practice, it is often difficult to divide a program in such a way that separate CPUs can execute different portions without interfering with each other. First proposed in the 1970s, quantum computing relies on quantum physics by taking advantage of certain quantum physics properties of atoms or nuclei that allow them to work together as quantum bits, or qubits, to be the computer's processor and memory. By interacting with each other while being isolated from the external environment, qubits can perform certain calculations exponentially faster than conventional computers. Qubits do not rely on the traditional binary nature of computing. While traditional computers encode information into bits using binary numbers, either a 0 or 1, and can only do calculations on one set of numbers at once,quantum computers encode information as a series of quantum-mechanical states such as spin directions of electrons or polarization orientations of a photon that might represent a 1 or 0, might represent a combination of the two or might represent a number expressing that the state of the qubit is somewhere between 1 and 0, or a superposition of many different numbers at once. A quantum computer can do an arbitrary reversible classical computation on all the numbers simultaneously, which a binary system cannot do, and also has some ability to produce interference between various different numbers. By doing a computation on many different numbers at once, then interfering the results to get a single answer, a quantum computer has the potential to be much more powerful than a

classical computer of the same size. In using only a single processing unit, a quantum computer can naturally perform myriad operations in parallel. Quantum computing is not well suited for tasks such as word processing and email, but it is ideal for tasks such as cryptography and modeling and indexing very large databases. Nanotechnology is a field of science whose goal is to control individual atoms and molecules to create computer chips and other devices that are thousands of times smaller than current technologies permit. Current manufacturing processes use lithography to imprint circuits on semiconductor materials. While lithography has improved dramatically over the last two decades to the point where some manufacturing plants can produce circuits smaller than one micron (1,000 nanometers) – it still deals with aggregates of millions of atoms. It is widely believed that lithography is quickly approaching its physical limits. To continue reducing the size of semiconductors, new technologies that juggle individual atoms will be necessary. This is the realm of nanotechnology. Although research in this field dates back to Richard P. Feynman's classic talk in 1959, the term nanotechnology was first coined by K. Eric Drexler in1986 in the book Engines of Creation. In the popular press, the term nanotechnology is sometimes used to refer to any sub-micron process, including lithography. Because of this, many scientists are beginning to use the term molecular nanotechnology when talking about true nanotechnology at the molecular level. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization. Here natural language means a human language. For example, English, French, and Chinese are natural languages. Computer languages, such as FORTRAN and C, are not. Probably the single most challenging problem in computer science is to develop computers that can understand natural languages. So far, the complete solution to this problem has proved elusive, although great deal of progress has been made. Fourth-generation languages are the programming languages closest to natural languages.

8. Classification of Computers

Computers are classified according to their data processing speed, amount 0 of data that they can hold and price. Generally, a computer with high processing speed and large internal storage is called a big computer. Due to rapidly improving technology, we are always confused among the categories of computers. Depending upon their speed and memory size, computers are classified into following four main groups.

Supercomputer
Mainframe computer
Mini computer
Microcomputer

Supercomputer

Supercomputer is the most powerful and fastest, and also very expensive. It was developed in 1980s. It is used to process large amount of data and to solve the complicated scientific problems. It can perform more than one trillions calculations per second. It has large number of processors connected parallel. So parallel processing is done in this computer. In a single supercomputer thousands of users can be connected at the same time and the supercomputer handles the work of each user separately.

Super computer are mainly used for:

Weather forecasting
Nuclear energy research
Aircraft design
Automotive design
Online banking
To control industrial units

The supercomputers are used in large organizations, research laboratories, aerospace centers, large industrial units etc. Nuclear scientists use supercomputers to create and analyze models of nuclear fission and fusions, predicting the actions and reactions of millions of atoms as they interact. The examples of supercomputers are CRAY-1, CRAY-2, Control Data CYBER 205 and ETA A-10 etc.

Mainframe Computers

Mainframe computers are also large-scale computers but supercomputers are larger than mainframe. These are also very expensive. The mainframe computer specially requires a very large clean room with air-conditioner. This makes it very expensive to buy and operate. It can support a large number of various equipment’s. It also has multiple processors. Large mainframe systems can handle the input and output requirements of several thousands of users. For example, IBM, S/390 mainframe can support 50,000 users simultaneously. The users often access then mainframe with terminals or personal computers.

There are basically two types of terminals used with mainframe systems.

Dumb Terminal: Dumb terminal does not have its own CPU and storage devices. This type of terminal uses the CPU and storage devices of mainframe system. Typically, a dumb terminal consists of monitor and a keyboard (or mouse).
Intelligent Terminal: Intelligent terminal has its own processor and can perform some processing operations. Usually, this type of terminal does not have its own storage. Typically, personal computers are used as intelligent terminals. A personal computer as an intelligent terminal gives facility to access data and other services from mainframe system. It also enables to store and process data locally.

The mainframe computers are specially used as servers on the World Wide Web. The mainframe computers are used in large organizations such as Banks; Airlines and Universities etc. where many people (users) need frequent access to the same data, which is usually organized into one or more huge databases. IBM is the major manufacturer of mainframe computers. The examples of mainframes are IBM S/390, Control DataCYBER 176 and Amdahl 580 etc.

Minicomputers

These are smaller in size, have lower processing speed and also have lower cost than mainframe. These computers are known as minicomputers because of their small size as compared to other computers at that time. The capabilities of a minicomputer are between mainframe and personal computer. These computers are also known as midrange computers. The minicomputers are used in business, education and many other government Fundamentals of Computer and IT departments. Although some minicomputers are designed for a single user but most are designed to handle multiple terminals. Minicomputers are commonly used as servers in network environment and hundreds of personal computers can be connected to the network with a minicomputer acting as server like mainframes, minicomputers are used as web servers. Single user minicomputers are used for sophisticated design tasks. The first minicomputer was introduced in the mid-1960s by Digital Equipment Corporation (DEC). After this IBM Corporation (AS/400 computers) Data General Corporation and Prime Computer also designed the mini computers.

Microcomputer

The microcomputers are also known as personal computers or simply PCs. Microprocessor is used in this type of computer. These are very small in size and cost. The IBM’s first microcomputer was designed in 1981 and was named as IBM-PC. After this many computer hardware companies copied the design of IBM-PC. The term “PC-compatible” refers any personal computer based on the original IBM personal computer design. The most popular types of personal computers are the PC and the Apple. PC and PC-compatible computers have processors with different architectures than processors in Apple computers. These two types of computers also use different operating systems. PC and PC-compatiblecomputers use the Windows operating system while Apple computers use the Macintosh operating system (MacOS). The majority of microcomputers sold today are part of IBM-compatible. However the Apple computer is neither an IBM nor a compatible. It is another family of computers made by Apple computer.

Personal computers are available in two models. These are:

Desktop PCs
Tower PCs

A desktop personal computer is most popular model of personal computer. The system unit of the desktop personal computer can lie flat on the desk or table. In desktop personal computer, the monitor is usually placed on the system unit.

Another model of the personal computer is known as tower personal computer. The system unit of the tower PC is vertically placed on the desk of table. Usually the system unit of the tower model is placed on the floor to make desk space free and user can place other devices such as printer, scanner etc. on the desktop. Today computer tables are available which are specially designed for this purpose. The tower models are mostly used at homes and offices.

Microcomputers are further divided into following categories.

Laptop computer
Workstation
Network computer
Handheld computer

Laptop computer

Laptop computer is also known as notebook computer. It is small size (85- by-11 inch notebook computer and can fit inside a briefcase. The laptop computer is operated on a special battery and it does not have to be plugged in like desktop computer. The laptop computer is portable and fully functional microcomputer. It is mostly used during journey. It can be used on your lap in an airplane. It is because it is referred to as laptop computer. The memory and storage capacity of laptop computer is almost equivalent to the PC or desktop computer. It also has the hard disc, floppy disk drive, Zip disk drive, CD-ROM drive, CD-writer etc.

It has built-in keyboard and built-in trackball as pointing device. Laptop computer is also available with the same processing speed as the most powerful personal computer. It means that laptop computer has same features as personal computer. Laptop computers are more expensive than desktop computers. Normally these computers are frequently used in business travelers.

Workstations

Workstations are special single user computers having the same features as personal computer but have the processing speed equivalent to minicomputer or mainframe computer. A workstation computer can be fitted on a desktop. Scientists, engineers, architects and graphic designers mostly use these computers. Workstation computers are expensive and powerful computers. These have advanced processors, more RAM and storage capacity than personal computers. These are usually used as single-user applications but these are used as servers on computer network and web servers as well.

Network computers

Network computers are also version of personal computers having less processing power, memory and storage. These are specially designed as terminals for network environment. Some types of network computers have no storage. The network computers are designed for network, Internet or Intranet for data entry or to access data on the network. The network computers depend upon the network’s server for data storage and to use software. These computers also use the network’s server to perform some processing tasks.

In the mid-1990s the concept of network computers became popular among some PC manufacturers. As a result several variations of the network computers quickly became available. In business, variations of the network computer are Windows terminals, NetPCs and diskless workstations. Some network computers are designed to access only the Internet or to an Intranet. These devices are sometimes called Internet PCs, Internet boxes etc. In home some network computers do not include monitor. These are connected to home television, which serves as the output devices. A popular example of a home-based network computer is Web TV, which enables the user to connect a television to the Internet. The Web TV has a special set-top box used to connect to the Internet and also provides a set of simple controls which enable the user to navigate the Internet, send and receive e-mails and to perform other tasks on the network while watching television. Network computers are cheaper to purchase and to maintain than personal computers.

Handheld computer

In the mid 1990s, many new types of small personal computing devices have been introduced and these are referred to as handheld computers. These computers are also referred to as Palmtop Computers. The handheld computers sometimes called Mini-Notebook Computers. The type of computer is named as handheld computer because it can fit in one hand while you can operate it with the other hand. Because of its reduced size, the screen of handheld computer is quite small. Similarly it also has small keyboard. The handheld computers are preferred by business traveler. Some handheld computers have a specialized keyboard. These computers are used by mobile employees, such as meter readers and parcel delivery people, whose jobs require them to move from place to place.

The examples of handheld computers are:

Personal Digital Assistance
Cellular telephones
H/PC Pro devices

Personal Digital Assistance (PDAs)

The PDA is one of the more popular lightweight mobile devices in use today. A PDA provides special functions such as taking notes, organizing telephone numbers and addresses. Most PDAs also offer a variety of other application software such as word processing, spreadsheet and games etc. Some PDAs include electronic books that enable users to read a book on the PDA’s screen. Many PDAs are web-based and users can send/receive e-mails and access the Internet. Similarly, some PDAs also provide telephone capabilities. The primary input device of a PDA is the stylus. A stylus is an electronic pen and looks like a small ballpoint pen. This input device is used to write notes and

store in the PDA by touching the screen. Some PDAs also support voice input.

Cellular phones

A cellular phone is a web-based telephone having features of analog and digital devices. It is also referred to as Smart Phone. In addition to basic phone capabilities, a cellular phone also provides the functions to receive and send e-mails & faxes and to access the Internet.

H/PC Pro Devices

H/PC Pro device is new development in handheld technology. These systems are larger than PDAs but they are not quite as large as typical notebook PCs. These devices have features between PDAs and notebook PCs. The H/PC Pro device includes a full-size keyboard but it does not include disk. These systems also have RAM with very low storage capacity and slow speed of processor.

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