Characteristics Of Computer Generations 431o5u

A PROJECT REPORT ON

COMPUTER

SUBMITTED BY

NUPUR SRIVASTAVA

SUBMITTED TO BRAHASPATI MAHILA MAHA VIDYALAYA, KIDWAI NAGAR, KANPUR 1

CONTENTS 1. Characteristics of computer generations

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2. Input and output devices

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3. Block diagram of computer

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4. Introduction of number system

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5. Parts of computer system

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6. Types of computer

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7. Software and its varieties

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8. Limitation of computer

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CHARACTERISTICS OF COMPUTER GENERATIONS First Generation (1940-1956) Vacuum Tubes The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. 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, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, 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.

A UNIVAC computer at the Census Bureau. Image Source: United States Census Bureau Second Generation (1956-1963) Transistors Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. 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 3

programming languageswere 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 (1964-1971) 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. Instead of punched cards and printouts, s interacted with third generation computers through keyboardsand monitors and interfaced with an operating system, which allowed the device to run many differentapplications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors. Fourth Generation (1971-Present) Microprocessors The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip. In

1981 IBM introduced

its

first

computer

for

the

home

,

and

in

1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors. As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.

Fifth Generation (Present and Beyond) Artificial Intelligence

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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. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular andnanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

INPUT AND OUTPUT DEVICES Before a computer can process your data, you need some method to input the data into the machine. The device you use will depend on what form this data takes (be it text, sound, artwork, etc.). Similarly, after the computer has processed your data, you often need to produce output of the results. This output could be a display on the computer screen, hardcopy on printed pages, or even the audio playback of music you composed on the computer. The “input” and “output” are used both as verbs to describe the process of entering or displaying the data, and as nouns referring to the data itself entered into or displayed by the computer. Below we discuss the variety of peripheral devices used for computer input and output. INPUT DEVICES Keyboard The computer keyboard is used to enter text information into the computer, as when you type the contents of a report. The keyboard can also be used to type commands directing the computer to perform certain actions. Commands are typically chosen from an on-screen menu using a mouse, but there are often keyboard shortcuts for giving these same commands.

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Pointing Devices The graphical interfaces (GUIs) in use today require some kind of device for positioning the on-screen cursor. Typical pointing devices are: mouse, trackball, touch pad, trackpoint, graphics tablet, joystick, and touch screen. Pointing devices, such as a mouse, connected to the PC via aserial ports (old), PS/2 mouse port (newer), or USB port (newest). Older Macs used ADB to connect their mice, but all recent Macs use USB (usually to a USB port right on the USB keyboard). Mouse The mouse pointing device sits on your work surface and is moved with your hand. In older mice, a ball in the bottom of the mouse rolls on the surface as you move the mouse, and internal rollers sense the ball movement and transmit the information to the computer via the cord of the mouse. The newer optical mouse does not use a rolling ball, but instead uses a light and a small optical sensor to detect the motion of the mouse by tracking a tiny image of the desk surface. Optical mice avoid the problem of a dirty mouse ball, which causes regular mice to roll unsmoothly if the mouse ball and internal rollers are not cleaned frequently.

Two-button mouse with scroll wheel

Wireless Macintosh mouse

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.

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Trackpoint Some sub-notebook computers (such as the IBM ThinkPad), which lack room for even a touch pad, incorporate atrackpoint, a small rubber projection embedded between the keys of the keyboard. The trackpoint acts like a little joystick that can be used to control the position of the on-screen cursor. Trackball The trackball is sort of like an upside-down mouse, with the ball located on top. You use your fingers to roll the trackball, and internal rollers (similar to what’s inside a mouse) sense the motion which is transmitted to the computer. Trackballs have the advantage over mice in that the body of the trackball remains stationary on your desk, so you don’t need as much room to use the trackball. Early laptop computers often used trackballs (before superior touch pads came along). Trackballs have traditionally had the same problem as mice: dirty rollers can make their cursor control jumpy and unsmooth. But there are modern optical trackballs that don’t have this problem because their designs eliminate the rollers.

Joysticks Joysticks and other game controllers can also be connected to a computer as pointing devices. They are generally used for playing games, and not for controlling the on-screen cursor in productivity software. Touch screen Some computers, especially small hand-held PDAs, have touch sensitive display screens. The can make choices and press button images on the screen. You often use a stylus, which you hold like a pen, to “write” on the surface of a small touch screen.

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Graphics tablet A graphics tablet consists of an electronic writing area and a special “pen” that works with it. Graphics tablets allows 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).

Scanners A scanner is a device that images a printed page or graphic by digitizing it, producing an image made of tiny pixels of different brightness and color values which are represented numerically and sent to the computer. Scanners scan graphics, but they can also scan pages of text which are then run through OCR (Optical Character Recognition) software that identifies the individual letter shapes and creates a text file of the page's contents. 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. MIDI Devices MIDI (Musical Instrument Digital Interface) is a system designed to transmit information between electronic musical instruments. A MIDI musical keyboard can be attached to a computer and allow a performer to play music that is captured by the computer system as a sequence of notes with the associated timing (instead of recording digitized sound waves).

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OUTPUT DEVICES CRT Monitor The traditional output device of a personal computer has been the CRT (Cathode Ray Tube) monitor. Just like a television set (an older one, anyway) the CRT monitor contains a large cathode ray tube that uses an electron beam of varying strength to “paint” a picture onto the color phosphorescent dots on the inside of the screen. CRT monitors are heavy and use more electrical power than flat displays, but they are preferred by some graphic artists for their accurate color rendition, and preferred by some gamers for faster response to rapidly changing graphics.

Ink Jet Printer For hardcopy (printed) output, you need some kind of printer attached to your computer (or available over a network). The most common type of printer for home systems is the color ink jet printer. These printers form the image on the page by spraying tiny droplets of ink from the print head. The printer needs several colors of ink (cyan, yellow, magenta, and black) to make color images. Some photo-quality ink jet printers have more colors of ink. Laser Printer A laser printer produces good quality images by the same technology that photocopiers use. A drum coated with photosensitive material is charged, then an image is written onto it by a laser (or LEDs) which makes those areas lose the charge. The drum then rolls through toner (tiny plastic particles of pigment) that are attracted to the charged areas of the drum. The toner is then deposited onto the paper, and then fused into the paper with heat. Sound Output Computers also produce sound output, ranging from simple beeps alerting the , to impressive game sound effects, to concert quality music. The circuitry to produce sound may be included on the motherboard, but high quality audio output from a PC usually requires a sound card in one of the expansion slots, connected to a set of good quality external speakers or headphones.

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BLOCK DIAGRAM OF COMPUTER A computer can process data, pictures, sound and graphics. They can solve highly complicated problems quickly and accurately. A computer as shown in Fig. performs basically five major computer operations or functions irrespective of their size and make. These are: 1) it accepts data or instructions by way of input, 2) it stores data, 3) it can process data as required by the , 4) it gives results in the form of output, and 5) it controls all operations inside a computer.

INTRODUCTION OF NUMBER SYSTEM Human beings use a 10 based or decimal number system, possibly because we have tens fingers and ten toes. Computers use a 2 based or binary system because it can be represented easily in hardware by on-off, open-closed, charged-uncharged states. For example a capacitor in RAM memory can be charged or not charged. A charged state represents a 1 and an uncharged (or not fully charged) state represents a 0. Likewise data stored on a hard disk at the molecular level can be magnetically aligned in one pattern or its opposite. Each pattern represents a 1 or 0. 10

Decimal numbers can be converted to binary numbers, and vice-versa. This is essential as humans work in decimals and computers work in binary. The pages in this menu look at how to use each system and how they relate to each other. A look is also taken at the octal (base 8) and hexadecimal (base 16) systems. There are three Scratch files attached to this page that demonstrate the decimal, binary and hexadecimal number systems.

PARTS OF COMPUTER SYSTEM If you use a desktop computer, you might already know that there isn't any single part called the "computer." A computer is really a system of many parts working together. The physical parts, which you can see and touch, are collectively calledhardware. (Software, on the other hand, refers to the instructions, or programs, that tell the hardware what to do.) The following illustration shows the most common hardware in a desktop computer system. Your system might look a little different, but it probably has most of these parts. A laptop computer has similar parts but combines them into a single, notebook-sized package.

Desktop computer system Let's take a look at each of these parts. 11

System unit The system unit is the core of a computer system. Usually it's a rectangular box placed on or underneath your desk. Inside this box are many electronic components that process information. The most important of these components is the central processing unit (U), or microprocessor, which acts as the "brain" of your computer. Another component is random access memory (RAM), which temporarily stores information that the U uses while the computer is on. The information stored in RAM is erased when the computer is turned off. Almost every other part of your computer connects to the system unit using cables. The cables plug into specific ports(openings), typically on the back of the system unit. Hardware that is not part of the system unit is sometimes called aperipheral device or device.

System unit Storage Your computer has one or more disk drives—devices that store information on a metal or plastic disk. The disk preserves the information even when your computer is turned off. Hard disk drive Your computer's hard disk drive stores information on a hard disk—a rigid platter or stack of platters with a magnetic surface. Because hard disks can hold massive amounts of information, they usually serve as your computer's primary means of storage, holding almost all of your programs and files. The hard disk drive is normally located inside the system unit.

Hard disk drive

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CD and DVD drives Nearly all computers today come equipped with a CD or DVD drive, usually located on the front of the system unit. CD drives use lasers to read (retrieve) data from a CD; many CD drives can also write (record) data onto CDs. If you have a recordable disk drive, you can store copies of your files on blank CDs. You can also use a CD drive to play music CDs on your computer.

CD DVD drives can do everything that CD drives can, plus read DVDs. If you have a DVD drive, you can watch movies on your computer. Many DVD drives can record data onto blank DVDs. Mouse A mouse is a small device used to point to and select items on your computer screen. Although mice come in many shapes, the typical mouse does look a bit like an actual mouse. It's small, oblong, and connected to the system unit by a long wire that resembles a tail. Some newer mice are wireless.

Mouse Keyboard A keyboard is used mainly for typing text into your computer. Like the keyboard on a typewriter, it has keys for letters and numbers, but it also has special keys:  

The function keys, found on the top row, perform different functions depending on where they are used. The numeric keypad, located on the right side of most keyboards, allows you to enter numbers quickly. 13

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The navigation keys, such as the arrow keys, allow you to move your position within a document or webpage.

Keyboard Monitor A monitor displays information in visual form, using text and graphics. The portion of the monitor that displays the information is called the screen. Like a television screen, a computer screen can show still or moving pictures. There are two basic types of monitors: CRT (cathode ray tube) monitors and the newer LCD (liquid crystal display) monitors. Both types produce sharp images, but LCD monitors have the advantage of being much thinner and lighter.

LCD monitor (left); CRT monitor (right)

Printer A printer transfers data from a computer onto paper. You don't need a printer to use your computer, but having one allows you to print e-mail, cards, invitations, announcements, and other material. Many people also like being able to print their own photos at home. The two main types of printers are inkjet printers and laser printers. Inkjet printers are the most popular printers for the home. They can print in black and white or in full color and can produce high-quality photographs when used with special paper. Laser printers are faster and generally better able to handle heavy use.

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Inkjet printer (left); laser printer (right) Speakers Speakers are used to play sound. They can be built into the system unit or connected with cables. Speakers allow you to listen to music and hear sound effects from your computer.

Computer speakers Modem To connect your computer to the Internet, you need a modem. A modem is a device that sends and receives computer information over a telephone line or high-speed cable. Modems are sometimes built into the system unit, but higher-speed modems are usually separate components.

Cable modem 15

TYPES OF COMPUTER The types of computers range from the Hybrid to the Analog types. The computers you come across in the daily course of your day range from laptops, palmtops and towers, to desktop computers, to name a few. But the very word "computers" reminds one of the desktop computers used in offices or homes. Different categories of computes have been devised in keeping with our varied needs. The Types Of Computers:Analog and Hybrid (classification based on operational principle)  Analog Computers : The analog computer is almost an extinct type of computer these days. It is different from a digital computer in respect that it can perform numerous mathematical operations simultaneously. It is also unique in of operation as it utilizes continuous variables for the purpose of mathematical computation. It utilizes mechanical, hydraulic, or electrical energy or operation. 

Hybrid computers : These types of computers are, as the name suggests, a combination of both Analog and Digital computers. Apart from this, computers are also categorized on the basis of physical structures and the purpose of their use. Based on Capacity, speed and reliability they can be divided into three categories of computers : 1. The Mainframe Computer : These are computers used by large organizations like meteorological surveys and statistical institutes for performing bulk mathematical computations. They are core computers which are used for desktop functions of over one hundred people simultaneously. 2. The Microcomputer : These are the most frequently used computers better known by the name of "Personal computers". This is the type of computer meant for public use. Other than Desktop Computer the choice ranges as follows :  Personal Digital Computer  Tablet PC  Towers  Work Stations  Laptops  Hand Held Computer

3. The Mini computer : Mini computers like the mainframe computers are used by business organization. The difference being that it can the simultaneous working of up to 100 s and is usually maintained in business organizations for the maintenance of s and finances. 16

Analog Computers : Analog Computers and Digital computers are the two kinds of computers, the combination of which is responsible for the invention of the modern Hybrid computers. Digital Computers : Digital Computers are that kind of computing machines which work on the principle of binary mathematics. Digital computing machines when clubbed with Analog computers produce Hybrid computers. The digital systems work on the principle of binary mathematics. In binary mathematics all calculations are represented through "0" and "1". Mainframe Computer : Mainframes are computers that are the most bulky types and with the advancement of technology, they have almost become extinct. Computers are of three types - Mainframe computers, Minicomputers and Microcomputers. Mainframe computer systems can be called the predecessor of servers because they could actually multi s though as efficiently as the servers. Usually, a main frame would occupy an entire room and could cost over million dollars. Minicomputers : Minicomputers, what exactly are they? If supercomputers and mainframes are considered to be the best in of mathematical operations then minicomputer systems succeed them. Previously,minicomputers were considered to be superior to personal systems. But these days, advancement intechnology has made minicomputers almost obsolete because the PCs today are highly advanced. Supercomputers : Supercomputers are one of the many types of modern computing machines which are capable of giving very speedy calculations. It is because of their high speed processing ability that Supercomputer systems are used in such works as animation graphics, weather forecasting, nuclear research work, petroleum research works, crypt analysis, molecular modeling and the likes. You must be wondering then what is the difference between a supercomputer and a mainframe computer system? While Mainframe machines are primarily used for a number of purposes, supercomputers are so designed to serve a singular purpose.

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SOFTWARE AND ITS VARIETY Types of Computer Software Designed to store data, a computer is able to function in different and desired ways only due to a number of software applications that empower it. Various types of computer software help it execute a variety of operations every day. Computer software is available in different forms and types. Classification of Computer Software Broadly, computer software can be classified into three categories. One, system software is the most important component for running a system or computer. System software is also known as operating system which helps start a computer and works as a main platform in order to run any application. A number of operating systems are in vogue that empower systems globally. However, these operating systems have a category of server and personal computer operating systems. Customization vs Off-the-shelf software In addition, any individual software package, which may fall into any of the above categories, can be either 'off-the-shelf' or custom-built. Both are different and address different levels of demands. Applications such as ERP, CRM and BI, when implemented into any enterprise, are usually customized in order to make them gel with the business processes of that enterprise. It usually happens because of the scale and nature of a business.

LIMITATIONS OF COMPUTER The computer can outperform human beings in speed, memory and accuracy but still the computer has limitations. There are following limitations of a computer. Programmed by human: Though computer is programmed to work efficiently, fast and accurately but it is programmed by human beings to do so. Without a program, computer is nothing. A program is a set of instructions. Computer only follows theseinstructions. If the instructions are not accurate the working of computer will not accurate. Thinking:

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The computer can not think itself. The concept of artificial intelligenceshows that the computer can think. But still this concept is dependent on set of instructions provided by the human beings. Self Care: A Computer can not care itself like a human. A computer is dependent still to human beings for this purpose. Retrieval of memory: A computer can retrieve data very fast but this technique is linear. A human being's mind does not follow this rule. A human mind can think randomly which a computer machine can not. Feelings: One of the main limits in the computer is of feeling. A computer can not feel about some like a human. A computer can not meet human in respect of relations. Human can feel, think and caring but a computer machine itself can not. A computer can not take place of human because computer is always dependent of human.

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