Microsoft Word - CS XI 2015 PDF.docx

[Audio] CHAPTER ONE CHAPTER ONE CHAPTER ONE CHAPTER ONE 1 INTRODUCTION TO INTRODUCTION TO INTRODUCTION TO INTRODUCTION TO COMPUTER COMPUTER COMPUTER COMPUTER OBJECTIVE: When you have completed this chapter, you will be able to know about the Short Answer Questions Q1. Define Computer. Why computers are used? Q2. What is computer science and information technology? Q3. What type of device a computer is? And how it is used? Q4. What are the types of computer according to mechanism? Q5. Define and explain computer system in short. Long Answer Questions Q1. Write a note on modern computer. Q2. What are the types of computer according to mechanism? Q3. What are the characteristics of the computer system? Describe briefly. Q4. What are the main concerns or parts and parcels for a computer system? Page 4 of 157 VER: 04.

[Audio] CHAPTER #1 INTRODUCTION TO COMPUTER ===========Short Questions and Answers========= Q1. Define Computer. Why computers are used? Computer In general computer is defined as a device which is used for calculation. OR A computer is a device which takes data as input, process the data and gives us the output in the form of information. OR Any data processing device is called computer. Explanation: The first use of the word "computer" was recorded in 1613, referring to a person who carried out calculations, or computations, and the word continued with the same meaning until the middle of the 20th century. From the end of the 19th century onwards, the word began to take on its more familiar meaning, describing a machine that carries out computations. Example Speedometer Thermometer Measuring equipment of petrol pump Calculator Electronic Computer An electronic computer Is defined as a device which is used for computation and it is based on digital mechanism OR An electronic device which takes data as input and gives output after digital processing. Example Micro Computers (PC) Mainframe Computers Super Computers Page 5 of 157 VER: 04.

[Audio] Q2. What is computer science and information technology? Computer Science Computer science is a branch of electronics in which we study about the architecture, functions, programming and administration of a computer system.  Explanation In computer science we discuss about the hardware and software architecture. Computer functions and procedure are also discussed in computer science. A computer student may study to become hardware engineer or software programmer. Computer science is the study of computer- namely, their design (architecture) and their uses for computations, data processing, and systems control. Computer science includes engineering activities such as the design of computers means hardware and software that make up the computer system. Information Technology (IT) The information technology is the mergence of two technologies that is computer science and communication technology.  Explanation When a computer is used for the communication it is called Information Technology (IT). The Information Technology provides comprehensive solutions for any business or technical organization. Information Technology provides various features like internet and other communication networks. Q3. What type of device a computer is? And how it is used? Definition The term computer is derived from the word "compute" which means to calculate. So a computer is normally considered to be a calculating device that can perform arithmetic operation at enormous speed.  Computer is a device that accepts input as data, process according to prescribed steps of instructions and provides the output of the processed information or data called result.   Computer is a machine, which receives information, process it and present it in an arranged manner.   Computer is a device which is capable of accepting data, applying described process to data and supplying results of their processes.   Computer is known as an electronic computational device having internal storage, having a stored program of instructions and capability for modification of the set of instruction at any time.   Computer is a machine that accepts data, processes it and gives output.   Computer is an atomic electronic calculating device or machine that can perform logical and arithmetical operations.   Computer is a fast and accurate electronic symbol manipulating system that is designed to automatically accept and store input data, process it and produce result (output) under the direction of a stored procedure.   Computer is an electronic device which converts data/information into meaning full results or information. Page 6 of 157 VER: 04.

[Audio] Q4. What are the types of computer according to mechanism? The computer systems have been divided into three main categories regarding their internal mechanism. Now we explain all the types one by one. Analog Computers Analog computers are the calculating or measuring devices which have physical mechanism for data processing.  Examples Speedometer of a car Thermometer Analog Watch Digital Computers A digital computer is defined as an electronic device which is used for data processing. The data is processed digitally.  Examples  Micro Computers Mainframe Computers Super Computers Hybrid Computers A hybrid computer is defined as a computer which has both the characteristics of a digital and analog computers. It contains physical mechanism but process digitally.  Examples Modern Petrol Pump equipment Q5. Define and explain computer system in short Computer System A system is a group of integrated parts that have the common purpose of achieving some objective(s). So, the following three characteristics are key to a system. 1. A system has more than one element. 2. All the elements of a system are logically related. 3. All the elements of a system are controlled in such a way that the system goal is achieved. Since a computer is made up of integrated components (input and output devices, storage, CPU) that work together to perform the steps called for in the program being executed, it is a system. The input or output units cannot function until they receive signals from the CPU. The CPU alone is of no use. So the usefulness of each unit depends on other units and can be realized only when all units are put together (Integrated) to form a system. =========== Long Questions and Answers========= Q1. Write a note on modern computer. An electronic computer Is defined as a device which is used for computation and it is based on digital mechanism. OR An electronic device which takes data as input and gives output after digital processing. Page 7 of 157 VER: 04.

[Audio] Example Micro Computers (PC) Mainframe Computers Super Computers Modern Computer A modern computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem. Conventionally a computer consists of some form of memory for data storage, at least one element that carries out arithmetic and logic operations, and a sequencing and control element that can change the order of operations based on the information that is stored. Peripheral devices allow information to be entered from an external source, and allow the results of operations to be sent out. Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into mobile devices, and mobile computers can be powered by small batteries. Personal computers in their various forms are icons of the Information Age and are what most people think of as "computers". However, the embedded computers found in many devices from mp3 players to fighter aircraft and from toys to industrial robots are the most numerous. Q2. What are the types of computer according to mechanism? The computer systems have been divided into three main categories regarding their internal mechanism. This division is based on the internal functionality of computer. The following are the three types of computers. 1. Analog Computers 2. Digital Computers 3. Hybrid Computers Now we explain all the types one by one. Analog Computers Analog computers are the calculating or measuring devices which have physical mechanism for data processing.  Explanation An analog computer may be any kind of equipment used for the sake of calculation. An analog computer has got physical mechanism for data processing. If the equipment is run by the current then definitely analog current is used. An analog computer is a form of computer that uses the continuously-changeable aspects of physical phenomena such as electrical,[1] mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities incrementally, as their numerical values change. Mechanical analog computers were very important in gun fire control in World War II and the Korean War; they were made in significant numbers. In particular, development of transistors made electronic analog computers practical, and before digital computers had developed sufficiently, they were commonly used in science and industry. Examples Speedometer of a car, Thermometer, Analog Watch Page 8 of 157 VER: 04.

[Audio] Digital Computers A digital computer is defined as an electronic device which is used for data processing. The data is processed digitally.  Explanation The digital computers do not contain any physical mechanism. These are run by the digital current. The data is presented in the form of digital numbers which are called Binary Numbers (0, 1). The data processing is done through ICs, Transistors and processors electronically. Digital computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space. Simple computers are small enough to fit into mobile devices, and mobile computers can be powered by small batteries. Personal computers in their various forms are icons of the Information Age and are what most people think of as "computers". However, the embedded computers found in many devices from mp3 players to fighter aircraft and from toys to industrial robots are the most numerous.  Examples Micro Computers, Mainframe Computers, Super Computers Hybrid Computers A hybrid computer is defined as a computer which has both the characteristics of a digital and analog computers. It contains physical mechanism but process digitally.  Explanation A hybrid computer contains both types of characteristics. Although the processing is digital but internally it contains physical mechanism for other measuring functions. A hybrid computer contains digital or analog current accordingly for physical functions and data processing.  Examples Modern Petrol Pump equipment Q3. What are the characteristics of the computer system? Describe briefly. A Computer System is a modern problem solving machine. It contains a number of features which makes it a special device. The following are some important characteristics of a computer system. 1. Extra-Ordinary Speed A computer is very fast device. It can process millions of instructions in a second. As compared to a human being it can perform calculations and logical decisions thousands of time earlier. A computer system's speed is measures in Hertz (Hz). 2. Highly Reliable Accuracy The processing done by a computer system is highly reliable. The degree of accuracy of the calculated results cannot be challenged. Although the accuracy depends on the size of the calculation and the speed of a processor but the human being can never perform huge calculation with 100% accuracy. 3. Diligence And Smart Behavior Unlike human being the computer system cannot be tired after working for a long time. It is free from lack of concentration, mental weakness, tiredness and sickness. A computer system can work non-stop for long time, performing calculations without committing mistakes and taking Page 9 of 157 VER: 04.

[Audio] decisions without any error. If ten million calculations have to be performed, a computer will perform the ten millionth calculation with exactly the same accuracy and speed as the first one. 4. Versatility And Multiple Role Behavior A computer system can perform any kind of task of processing. It can be used to solve any kind of problem. A computer system is used not only for business and technical problems but also to solve general life problems and even for entertainment. It can be used in offices, in large enterprises and even inside the houses. So a computer is capable of performing almost all kinds of tasks assigned to it. 5. Strong Memory A computer system possesses a highly strong memory. It can never forget facts and figures once provided to it. Unlike the human beings a computer system is able to remember for unlimited time. A computer can forget any data if and only if it is instructed to do so. It is a great quality of a computer system that it contains a highly strong memory. 6. No Quality Of IQ A computer system is supposed to do all kind of operations as these are programmed. A computer system cannot take decisions by itself. Its decision making skill is purely based on our instructions. Its IQ level is zero, so it cannot take its own decisions. 7. No Quality Of Feelings And Emotions Unlike the human beings a computer system does not have feelings and emotions. Due to this quality the computer system always perform right logical decisions. It cannot make judgment using feelings and emotions. Q4. What are the main concerns or parts and parcels for a computer system? The computer system is not only a device. It cannot work efficiently if its concerns are not working properly. A complete computer system consists of five parts. 1. Hardware 2. Software 3. Data 4. Procedure 5. People These all concerns are integrated with each other to build a complete computer system. 1. Hardware Hardware is the physical component of a computer system. In other words all the devices which are the parts of the machines are called Hardware.  Examples Input and output devices like keyboard, mouse and monitor Processing devices like CPU etc 2. Software The software are the non-physical components. These are stored logically on the storage media. In actual, the softwares are the programs to communicate with the computer system to solve user's problems.  Examples System Software like operating system Application Software like a word processor Page 10 of 157 VER: 04.

[Audio] 3. Data The data is the plural of the word "Datum" which means facts and figures in the form of raw material. The data is the basic component on which user want to perform processing. The processed data is called "Information". So the data is the main ingredient which is processed by the computer system.  Examples Data about all the customers of the bank Data about all the products of the medical company 4. Procedure The procedure is defined as a set of rules to follow a computer related task. A user needs to have a comprehensive guide line to use a particular hardware or software and to process data. The procedures may be in the form of user manuals, help files, study tours or tutorials.  Examples User Manuals Help Files 5. People/User The persons who are going to use hardware and software to process data by following procedure are called People/User. The people may be computer operators or application designers or any other executive working on the computer.  Example Computer operators System managers etc Page 11 of 157 VER: 04.

[Audio] CHAPTER TWO CHAPTER TWO CHAPTER TWO CHAPTER TWO 2 INPUT INPUT INPUT INPUT DEVICES DEVICES DEVICES DEVICES OBJECTIVE: When you have completed this chapter, you will be able to know about the Short Answer Questions Q1. How do you define Input, Output and process? Q2. Define input device and describe its types. Q3. What are non keyboard or direct input devices? Mention names of the all types. Q4. Explain voice input devices. Long Answer Questions Q1. What are the input devices categories used by a computer system? Q2. What are Scanning devices? Describes its types. Q3. Describe pointing devices in detail. Q4. What are the keyboard devices? Explain briefly. Q5. What are keyboard devices? Describe its functions and all kinds of keys in detail. Page 12 of 157 VER: 04.

[Audio] CHAPTER # 2 INPUT DEVICES ===========Short Questions and Answers========= Q1. How do you define Input, Output and process? Input The procedure of providing data and entering commands to the computer system is called Input. Output The procedure of getting information from the computer system is called Output. Process The work done by the computer system on the data is called Process. In the processing the data is converted into information. Q2. Define input device and describe its types. Input Devices In order to process data computer must have the ability to receive this data. The element of a computer system which enters the data into the computer is known as Input Device. The input devices translate given information into a form which computer can understand. The following are the kinds of input devices.  Keyboard Devices  Non keyboard Devices Q3. What are non keyboard or direct input devices? Mention names of the all types. Direct entry means that data is not entered into the computer through a keyboard. Some common direct-entry devices are used to input data into computer are as follows. 1. Scanning Devices  Bar-code reader  Mark and character reader  Image scanner   Fax machine 2. Voice-input devices  Mic 3. "Pointing" Devices.  Mouse,   Trackball,  Joystick,   Touch screen,  Light pen,   Digitizer,  Pen-based computer Q4. Explain voice input devices. The device which enables computer system to get input for the sound is called voice input device. Page 13 of 157 VER: 04.

[Audio] Explanation This input device is the latest innovation, which helps us, input data by actually talking to computer. This system requires a microphone, which takes the analog signals from voice and sends them to an analog to digital converter. This converter changes analog signal into digital signals, which are in the form of zeros and ones and called voice patterns. Example Microphone, mic ===========Long Questions and Answers========= Q1. What are the input devices categories used by a computer system? Input Devices The hardware which is used to enter data or commands into the computer system is called input device. Explanation Data may be entered in the form of characters, numbers, images, voice or even in the video form. For all these types of input different types of input devices are available. Types of input devices The following are the main three types of Input Devices. Keyboard Devices Pointing Devices Scanning Devices All these types have various categories of input devices which are as follows: 1. Keyboard Devices Computer Keyboard Touch tone Devices Set top box 2. Pointing Devices Mouse ( Trackball, Pointing sticks, Touch Pads ) Light Pens Digitizers Pen Based Systems 3. Scanning Devices Scanners Audio Input Devices Video Input Devices Q2. What are Scanning devices? Describes its types. Scanning devices use light-sensitive equipment to record data in the form of bar codes, optical marks, typewritten characters, or magnetic-ink symbols, or even just plain text or graphics. This data is then converted to electronic form that can be processed by the computer. 1. Bar-Code Reader A bar code is data represented in the parallel lines of a universal coding scheme. Bar codes are read by bar-code readers. Bar-code readers are photo-electric scanners that read bar codes by means of reflected light. Two types of bar-code readers are hand-held and stationary: Page 14 of 157 VER: 04.

[Audio]  Hand-Held: Hand-held bar-code readers are flat stick-like scanning devices that analyze the bar codes and translate them into computer-process able data.   Stationary: Stationary bar-code readers are built into a countertop as in the supermarket to analyze which products have been sold and which are not.  2. Mark And Character Reader Mark and character reader use a light source to read special marks or character and convert the data to computer-process able form. These include the following.  Optical Mark Recognition (OMR) "reads" pencil or pen marks, made in pre-defined positions on paper forms as responses to questions or tick list prompts   Optical Character Recognition (OCR) devices are designed to read sheets of paper, cards, Books or Journal tapes. It has ability to read marks, printed numerical, special characters, alphabets and hand written numerals and letters.   Magnetic-Ink Character Recognition (MICR) device read preprinted characters printed with special magnetic ink.  3. Image Scanner This input device is just like a photo state machine. It can read sheet of paper cards, books, picture diagrams and other paper material and converts them into computer-process able form. The following are the several types of scanners.  Flatbed: are Stationary scanners that hold the image document in place while the scanning mechanism passes over it. Flatbed scanners just like a photo state machine.   Sheet-Fed: are Stationary scanners that use mechanical rollers to move the image document passes the scanning mechanism.   Hand-held: scanner is movable scanners that require the scanning mechanism to be moved over the image document.  4. Fax Machine The word fax stands for "facsimile". A fax machine is transmission machine, which can send or receive pictures and text over a telephone line. Fax machine may be of two sorts.  Dedicated Fax Machine: Dedicated Fax machine do nothing except send and receive document over telephone lines. The messages are printed out on paper. There are the kinds of machine seen in many business.   Computers with Fax Modem: A Fax modem is an electronic circuit board installed in a computer. People send fax messages of document input to their computers. Message can be displayed on the computer screen or printed out. Q3. Describe pointing devices in detail. A device with which you can control the movement of the pointer to select items on a display screen Called pointing devices. Pointing device include the following. 1. Mouse Mouse is the most common input device, which allows the user to control a cursor on the monitor screen to manipulate data without complicated commands. It's also called a "Pointing Device". Page 15 of 157 VER: 04.

[Audio] 2. Trackball A track ball is a pointing device same as of mouse but is stationary and guided by the fingers instead of rolled on the desktop. Some computers have a built-in trackball. Track ball may also appear on the side of a computer keyboard. 3. Joystick A joystick is usually used to play games on computer. It is a device that controls the movement of certain object on the screen. The buttons on the joystick allow the users to perform different actions depending on the nature of the program. 4. Touch screen A touch screen is a special type of computer display screen that allows commands to be entered by the user's touching the screen. Labeled boxes on the screen display choices available to the user. Touch screens are generally used in the locations such as airports and hotels to display certain types of menu. 5. Light pen The light pen consists of a light-sensitive pen like device that enters commands into a special display screen when the user touches the screen with the pen. It is actually needed for engineering designing, graphic designers, and drafting engineers. Q4. What are the keyboard devices? Explain briefly. The Keyboard devices are the hardware which is used to enter data in the form of characters and numbers. It is also used to enter commands. The following are the main categories of keyboard devices: Computer Keyboard Touch tone Devices Set top Box Now we discuss these types in detail. 1. Computer Keyboard The computer keyboards are the conventional keyboards. It has 101 keys normally. It contains the following categories of keys: Character Keys Function Keys Special Purpose Keys Numeric Keys Cursor Movement Keys These keyboards are used normally with the micro computers and it is easily available. 2. Touch Tone Devices The touch tone devices are also called Push Button Devices which are used to send data to a computer system. A credit card machine is a touch tone device which is used to transfer amount by accessing a computer. 3. Set Top Boxes These are the smart keyboards used to enter commands remotely in wirelessly to televisions, monitor screens and other devices. The remote control of television is a famous example which is used to change the channels. Page 16 of 157 VER: 04.

[Audio] Q5. What are keyboard devices? Describe its functions and all kinds of keys in detail. Keyboard Devices Keyboard devices are those devices which enter the data in to computer by using keyboard. Keyboard Keyboard is a most common input device. Keyboard is used to enter commands and data input into a computer. It looks like a typewriter keyboard but has additional keys for specific purposes. Among IBM (International Business Machine) compatible computers, the most common keyboard layout is the IBM enhanced keyboard. The QWERTZ layout is widely used in Germany and much of Central Europe. The main difference between it and QWERTY is that Y and Z are swapped, and most special characters such as brackets are replaced by diacritical characters. Control processor Computer keyboards include control circuitry to convert key presses into key codes that the computer's electronics can understand. The key switches are connected via the printed circuit board in an electrical X-Y matrix where a voltage is provided sequentially to the Y lines and, when a key is depressed, detected sequentially by scanning the X lines. Keys of Keyboard It has 101 keys arranged in following five groups. 1. Character keys 2. Function keys 3. Special-purpose keys 4. Numeric keys 5. Cursor-movement keys Page 17 of 157 VER: 04.

[Audio] 1. Character Keys This is the main part of Keyboard by using this keypad the letters a→z, A→Z, numbers 0→9 and special characters like,! @#$ %^&*()_+}]{[">< etc. may be typed. Many of these characters are typed by holding Shift Key. 2. Function Keys A set of twelve keys (marked as F1 to F12) is located at the top of keyboard. All of these keys have pre-defined meanings which depend on the application software. 3. Special-Purpose Keys Some special functional keys are spread on keyboard like Ctrl (Control), Alt (Alternate), Esc (Escape), Home, PgUp, PgDn etc. special function keys are used to help enter and edit data and execute commands. 4. Numeric Keys This part or pad is located on the right side of keyboard. When "NUM LOCK" key is pressed then the numbers on numeric keypad can be used to enter numeric data. 5. Cursor-Movement Keys The cursor is the blinking symbol on the screen that shows where data may be entered next. The cursor movement keys, which are represented by directional arrow, move the cursor around the screen. Page 18 of 157 VER: 04.

[Audio] CHAPTER THREE CHAPTER THREE CHAPTER THREE CHAPTER THREE 3 OUTPUT OUTPUT OUTPUT OUTPUT DEVICES DEVICES DEVICES DEVICES OBJECTIVE: When you have completed this chapter, you will be able to know about the Short Answer Questions Q1. Define output device. Write a short note on soft copy and hardcopy output. Q2. What is computer output microfilm/microfiche (COM) system? Q3. Explain softcopy output hardware briefly. Q4. Define display unit and its major types shortly. Q5. Define impact and non impact printers. Long Answer Questions Q1. What is flat panel display? How many types of flat panel display are there? Explain in detail. Q2. What is hardcopy output hardware? Explain briefly. Q3. Write a note on impact printers. Q4. Write a note on non-impact printers Q5. Define and explain terminals. Page 19 of 157 VER: 04.

[Audio] CHAPTER # 3 OUTPUT DEVICES ===========Short Questions and Answers========= Q1. Define output device. Write a short note on soft copy and hardcopy output. Output devices convert machine-readable information into peoplereadable form. Output takes two forms:  Softcopy output   Hardcopy output Softcopy Softcopy means the output is in a form that cannot be physically touched, Softcopy output is best for information that needs to be viewed only occasionally or a few moments. The principal softcopy output devices are monitors and voice output devices. Hardcopy Hardcopy means the output is in a form that can be physically touched. The principal hardcopy output devices are printers, plotters, and microfilm output devices. Q2. What is computer output microfilm/microfiche (COM) system? (COM) is computer output produced as very small images on rolls or sheets of film. When the output is on rolls (usually 35 mm), it is microfilm. When the output is on sheets (4x6 inches), it is microfiche. The principal advantages of this technology are: 1. Speed: COM systems can easily handle output at a rate in excess of 30,000 lines per minute. This is about 50 percent faster than most large laser printers. 2. Size: The output is condensed in size (compared to hardcopy output) by a factor ranging from 20 to 100 3. Cost: The cost per page of printed material is less than that of regular hardcopy output methods. Q3. Explain softcopy output hardware briefly. Softcopy output devices are of two principal types.  Monitor   Sound output devices 1. Monitor This is the most commonly used form of output device when a permanent record is not required. A monitor is a television-like device used to display text and graphics from a computer. The monitor is also referred as screen, video display terminal (VDT) console, and cathode-ray tube (CRT). There are two main types of monitors:  Cathode-ray tube (CRT) monitor   Flat panel monitor 2. Sound Output Devices Sound output devices produce music, special-effects, noises, or other sounds. Page 20 of 157 VER: 04.

[Audio] Q4. Define display unit and its major types shortly. The display unit is the device which gives copy viewable output. Explanation Display unit is also referred as video display terminal (VDT) or monitor. It displays text and graphics and videos on the screen. Types  Cathode ray tube monitor  Monochrome Monitors Color Monitors  Flat panel display LCD ( Liquid crystal display) ELD ( Electroluminescent display) GPD ( Gas plasma display) Q5. Define impact and non impact printers. Impact Printers These Noisy printers print images physically striking an inked ribbon against papers with a hammer-like mechanism. In this sense, impact printers resemble typewriter. Impact printer can be grouped as  Serial or Character Printers  Line Printers Non Impact Printers This Kind of printer does not generate the kind of hammering noise that an impact printer does. Non impact printer produce high quality images which impact dot-matrix printer cannot. Following are the some common types of non-impact printer. Thermal Printer, Ink-Jet Printer, Laser Printer  Thermal Printer   Ink-jet Printer   Laser Printer ===========Long Questions and Answers========= Q1. What is flat panel display? How many types of flat panel display are there? Explain in detail. Flat panel display technology is particularly useful for laptop computers, which are small enough to fit in a brief case and powered by a small battery built into the computer. Types of flat panel display There are three types of flat panel monitors: 1. LCD ( Liquid crystal display) 2. ELD ( Electroluminescent display) 3. GPD ( Gas plasma display) LCD (Liquid crystal display) The LCD uses a clear liquid chemical trapped in tiny pockets between two pieces of glass. Each pocket of liquid is covered both front and back by very thin wires. When a small amount of current is applied to both wires, a chemical reaction turns the chemical a dark color. There by blocking light, the point of blocked light. The point of blocked light is the pixel. The principal advantages of LCD are Page 21 of 157 VER: 04.

[Audio] 1. Low power consumption 2. low cost 3. small size The biggest disadvantages are; 1. LCDs do not emit light, as a result, the image has very little contrast. 2. The screen is very susceptible to glare, so the optimum viewing angle is very narrow. 3. The resolution is not as good as that a CRT. Electroluminescent (EL) Display The EL display uses a thin film of solid, specially treated material that glows in response to electric current. To form a pixel on the screen, current is sent to the intersection of the appropriate row and column; the combined voltages from the row and column, cause the screen to glow at that point. EL displays provide the very high image resolution and excellent graphics capabilities. Fuel-color EL displays are expected soon. A disadvantage of the technology is its cost. Gas Plasma Display The gas-plasma display uses a gas that emits light when it is electrically charged. This technology resembles that of a moon light bulb. Depending on the mixture of glasses, the color displayed ranges from orange to red. The principal advantages of gas-plasma display are: 1. The images are much brighter than on a standard CRT. 2. The resolution is excellent. 3. The glare is not a significant problem. 4. The screen doesn't flicker like some CRTs. The main disadvantages are 1. only a single color is available (reddish orange) 2. The technology is expensive 3. It uses a lot of power 4. It does not show sharp contrast. Q2. What is hardcopy output hardware? Explain briefly. The device which is used to produce hardcopy output is called hardcopy hardware. Hardcopy output devices are of three principal types.  Printers  Plotters   Computer output microfilm/microfiche (COM) 1. Printers A device used for printing is known as "printer". It receives information from computer and prints it on the paper and the result of printer on paper is called the permanent copy or a "Hard Copy". Printers may be categorized according to the speed as low or high which are:-  Impact Printers  Non-Impact Printers  2. Plotters A plotter is a special kind of output device. It is like a printer in that it produces images on paper, but it does so in a different way. Plotters are designed to produce large drawings or images, such as construction plans for buildings. Page 22 of 157 VER: 04.

[Audio] 3. Computer output microfilm/microfiche (COM) (COM) is computer output produced as very small images on rolls or sheets of film. When the output is on rolls (usually 35 mm), it is microfilm. When the output is on sheets (4x6 inches), it is microfiche. The principal advantages of this technology are: 1. Speed: COM systems can easily handle output at a rate in excess of 30,000 lines per minute. This is about 50 percent faster than most large laser printers. 2. Size: The output is condensed in size (compared to hardcopy output) by a factor ranging from 20 to 100 3. Cost: The cost per page of printed material is less than that of regular hardcopy output methods. Q3. Write a note on impact printers. These Noisy printers print images physically striking an inked ribbon against papers with a hammer-like mechanism. In this sense, impact printers resemble typewriter. Impact printer can be grouped as  Serial or Character Printers  Line Printers  1. Serial or Character Printers Those printers which are capable to print only one character at a time called "Character Printers". These printers can print 10 to 600 characters per second and have only one printing head. Dot Matrix Printers & Daisy Wheel Printers are the examples of character printers.  Dot Matrix Printer Printer with only one head at a time one character prints and moves to next character position is called dot matrix printer. This character produced by an arrangement of tiny hammer like pins, which strike the ribbon against paper. These dots are arranged in a specified pattern to form characters. Dot Matrix printers can also prints drawings, graphics or pictures. It can print at a speed of 30 to 600 CPS (Characters per Second)  Daisy Wheel Printer In Daisy Wheel printer an electric motor spins a wheel and a print hammer strikes to produce image of character on paper. These printers cannot produce pictures drawing or graphic but print out is much better than Dot Matrix Printers. 2. Line Printer A line printer can print an entire line at a time which normally covers 80 or 132 characters and for each character have a separate printing head .Normally it can print about 250 lines per minute. Drum & Chain Printers are the examples of line Printers.  Drum Printer A DRUM printer consists of a solid cylindrical drum that has embossed characters in bands on its upper surface. On printing position many bands contains all the possible characters. The drum rotates at a high speed and for each location a print hammer is located behind the paper.  Chain Printer In CHAIN printer each character links with chain which moves and for every position there is a printing hammer located behind paper. When the chain rotates the properly timed print hammers strike paper.

[Audio] Q4. Write a note on non-impact printers This Kind of printer does not generate the kind of hammering noise that an impact printer does. Non impact printer produce high quality images which impact dot-matrix printer cannot. Following are the some common types of non-impact printer. Thermal Printer, Ink-Jet Printer, Laser Printer 1. Thermal Printer A thermal printer creates images by using colored waxes and heat in the pins of the print head to burn dots onto special paper. Thermal printers can provide the highest-quality desktop color printing available. However, they are expensive and require expensive paper. 2. Ink-jet Printer An ink-jet printer forms images by spraying tiny droplets of ink from jet nozzles onto the paper. Ink-jet printers using multiple nozzles can print in several different colors of ink. Color ink-jet printers produce excellent graphics. 3. Laser Printer These QUIET printers produce high quality printing and normally known as LASER (Light Amplification by stimulated Emission of Rays). HP 4L (Hewlett-Packard) is the example of laser printer. In these printers with the difference of electric charge laser exposed areas attract an ink powder called toner which is fused permanently on paper with heat or pressure. Only for 0.1-second heat fusing processes the temperature up to 200oc. Q5. Define and explain terminals. Terminals A terminal is an input (and output) device that consists of a keyboard, display screen, and communications connection to a main frame computer system. Terminals are used for inputting data to and retrieving data from a remotely located main frame computer system. There are three types of terminals:  Dumb Terminals   Smart Terminals  Intelligent Terminal 1. Dumb terminals Dumb Terminals are used only for data entry and retrieval. They cannot process data independently. It is used only to gain access to information from a main frame computer system. An example might be a terminal used by an airline reservations clerk. 2. Smart Terminals Smart terminal has some memory and hence can do limited processing as well as data entry and retrieval. A savings and loan manager might use a smart terminal to do simple computations on a customer's loan application before sending it to the company's mainframe computer. 3. Intelligent Terminal Intelligent terminals include processing unit, primary storage, secondary storage such as magnetic disk, and software for processing data. It can do independent processing of their own, as well as act as terminals. An intelligent terminal, which is also called a workstation, is actually a microcomputer with a communications link to a mainframe. Page 24 of 157 VER: 04.

[Audio] CHAPTER FOUR CHAPTER FOUR CHAPTER FOUR CHAPTER FOUR 4 SYSTEM UNIT SYSTEM UNIT SYSTEM UNIT SYSTEM UNIT AND AND AND AND PROCESSING DEVICES PROCESSING DEVICES PROCESSING DEVICES PROCESSING DEVICES OBJECTIVE: When you have completed this chapter, you will be able to know about the Short Answer Questions Q1. Define system unit. What are the components in a system unit? Q2. Define expansion cards and slots. Q3. What is the purpose of ports? Explain its types. Q4. What is meant by MIPS? Q5. What's a Chip? Long Answer Questions Q1. Define bus. What are various types of buses? Q2. What is the purpose of the power supply unit? Q3. What is the purpose of mother board? Describe Q4. What are processing devices? Explain the structure and functions of Central Processing Unit. Q5. Explain various features of the microprocessor. Page 25 of 157 VER: 04.

[Audio] CHAPTER # 4 SYSTEM UNIT AND PROCESSING DEVICES ===========Short Questions and Answers========= Q1. Define system unit. What are the components in a system unit? The machine of the computer system which holds all the processing and some storage devices is called system unit. The system unit contains the major components of the computer system which describes its configuration and defines the category of the computer system whether it is 386, 486, PI, PII, PIII, any other. The following are the components present in a system unit.  Power supply   Motherboard o C.P.U socket (Central processing Unit) o RAM slots (Random Access Memory) o BIOS chip ( Basic Input Output Unit) o PCI slots (Peripheral Components Interface) o IO ports (Input Output) o IDE (Integrated Drive Electronics) o Buses. Etc.  CD ROM  FDD   HDD Q2. Define expansion cards and slots. Expansion Cards and Slots Expansion slots are sockets on the motherboard into which expansion card may be plugged. The slot connects the expansion card with the power supply and the buses for moving data and instruction. Q3. What is the purpose of ports? Explain its types. Ports are connecting sockets on the outside of the system unit. This allows you to plug in other devices, such as monitor, keyboard, modem or printer. Cables connected to the ports transmit streams of bits, such as those in an 8-bit ASCII character, to the outside devices. Ports are of several types.  Serial Ports Serial ports are for connecting cables that transmit bits one after the other. Serial lines are used for connecting far-away devices, such as linking a modem to a telephone line.  Parallel Ports Parallel ports are for connecting cables that transmit several bits simultaneously. Parallel lines are used to connect devices located close by, such as a printer. Sending eight or so bits simultaneously transmits the information faster than is possible in a serial line. Page 26 of 157 VER: 04.

[Audio] Q4. What is meant by MIPS? MIPS stands for "millions of instructions per second" and is a rough measure of the performance of a CPU. Modern CPUs can do so many different things that MIPS ratings lose a lot of their meaning, but you can get a general sense of the relative power of the CPUs from this column. In general, there is a relationship between clock speed and MIPS. The maximum clock speed is a function of the manufacturing process and delays within the chip. There is also a relationship between the number of transistors and MIPS. For example, the 8088 clocked at 5 MHz but only executed at 0.33 MIPS (about one instruction per 15 clock cycles). Modern processors can often execute at a rate of two instructions per clock cycle. That improvement is directly related to the number of transistors on the chip and will make more sense in the next section. Q5. What's a Chip? A chip is also called an integrated circuit. Generally it is a small, thin piece of silicon onto which the transistors making up the microprocessor have been etched. A chip might be as large as an inch on a side and can contain tens of millions of transistors. Simpler processors might consist of a few thousand transistors etched onto a chip just a few millimeters square. ===========Long Questions and Answers========= Q1. Define bus. What are various types of buses? Buses In Microcomputer, the input/Output devices and memories are connected to the microprocessor by means of wires called buses. In simple words, a bus is a communication pathway connecting two or more devices. There are three types of buses called: 1. Address Buses 2. Data Buses 3. Control Buses 1. Address Buses The address buses are used by the microcomputer to transmit the address of memory location which it wants to access for reading or writing purpose. 2. Data Buses The data bus is used to transmit data from the memory to microprocessor. It may be used to transmit data to other devices such as output units. The data bus is bi-directional because data has to pass from microprocessor to memory as well as from memory to the microprocessor. Page 27 of 157 VER: 04.

[Audio] 3. Control Buses The Control bus supervises the reading or writing of data. It transmits signals to all the devices at the proper time. In fact, it informs the microprocessor that a particular unit has completed its job. Q2. What is the purpose of the power supply unit? The power supply unit is a device inside the system unit which converts Analog current into Digital current for the use of machine. Explanation All the devices inside the system unit need digital current to run. The current which is provided inside the homes and offices is analog current so it needs to be converted into digital current. Power supply provides current to various components of system unit according to requirements that may be 5-12 volts. Structure and Function Power supply contains an input socket for analog current of 220 volts. It contains an ATX (PI CONNECTOR) connector for mother board, same Molex connectors for hard disk and CD-ROMS and a mini-Molex connector for floppy drive. It also contains a P4 connector in Pentium 4 and above. Power supply unit is equipped with a fan which prevents it from heating problem. Major Types of Power Supply The following are the two types which are being used from a long time.  AT Power supply  ATX Power supply The AT (Advance Technology) power supply was being used in a Pentium 1 and 2 and earlier system units but the ATX (Advance Technology Extended) is being used for Pentium 3 and onwards system units. Q3. What is the purpose of mother board. Describe? Definition A mother board consists of flat circuit board in which all the devices are connected. Explanation Mother board is also called system board or main board of computer system. Mother board is a complex circuit board .All the input and output devices, storage and processing devices, IO cards and memory units are directly or indirectly connected to the mother board. Page 28 of 157 VER: 04.

[Audio] Components on the mother board The following are the components on the mother board. 1. C.P.U socket (Central processing Unit) 2. RAM slots (Random Access Memory) 3. BIOS chip ( Basic Input Output Unit) 4. PCI slots (Peripheral Components Interface) 5. IO ports (Input Output) 6. IDE (Integrated Drive Electronics) 7. Buses. Etc. Q4. What are processing devices? Explain the structure and functions of Central Processing Unit. Processing Devices The processing hardware are the electronic circuits inside the System Unit (SU). There may be more than one processing devices in different components of the computer system. The processing devices are available on the mother board and on expansion cards. Example 1. The Central Processing Unit on mother Board. 2. Processor of VGA Card. 3. Processor of Sound Card. Central Processing Unit The main unit of the computer system located on the mother board is the central processing unit. It is an electronic chip, which is the brain of the computer system. Explanation CPU is the main processing device, which processes data and instructions and calculates the desired output. It controls all the operations of the computer system. It is a complex electronic circuit that manages all kinds of arithmetic and logical operations. The central processing unit (CPU) is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the functions of the computer or other processing device. It carries out each instruction of the program in sequence, to perform the basic arithmetical, logical, and input/output operations of the system. In other words, the CPU is the "brains" of the computer. The term has been in use in the computer industry at least since the early 1960s. The form, design and implementation of CPUs have changed dramatically since the earliest examples, but their fundamental operation remains much the same. Each motherboard will support only a specific type or range of CPU so that one has to check the motherboard manufacturer's specifications before attempting to replace or upgrade a CPU. Modern CPUs also have an attached heat sink and small fan that go directly on top of the CPU to help dissipate heat. Page 29 of 157 VER: 04.

[Audio] Construction of CPU The basic unit of any processing chip is a transistor, which is an electronic switch and can represent the binary digits (0s and 1s). A transistor is composed of semi-conductor's PNP and NPN junction. Multiple Transistors construct on integrated circuit (IC). An IC is a basic processing unit and can make decisions by logic gates. Multiple ICs construct a micro-processor. A microprocessor is an advanced processing device. Components Of CPU The CPU contains three main components 1. Control Unit 2. Arithmetic Logic Unit 3. Cache Memory Control Unit The control unit is responsible for the execution of the programs. It not only controls the processes but also the IO interrupts. IO devices, memory units and storage media are controlled by the control unit. The flow of data and preferences of processing requests are handled by control unit. Its behavior is like a traffic police officer and it is responsible for flow of data. Arithmetic and Logic Unit The arithmetic and logic unit is responsible for the processing of data. The processing of data may be in the form of arithmetic operation like addition, subtraction, multiplication and division. The ALU is also able to take decisions on the basis of logics and conditions. Logical decisions means it can compare two values and can tell which one is greater. Cache Memory It is a temporary storage inside the CPU. It holds data which is being processed by the CPU. The cache memory is the fastest memory, it receives data from the main memory it holds the data until control unit directs it to provide data to ALU. Q5. Explain various features of the microprocessor. As computers have evolved, the size of the microprocessor has become smaller while its speed and capacity have increased tremendously. Indeed, the microprocessor, also called the CPU, is a tiny chip, about the size of your smallest fingernail, on which electronic circuitry has been etched. The chip is mounted on a piece of plastic, called carrier, with metal leafs attached to it. The microprocessor manages the computer processing and the transfer of data to and from primary storage, commonly called random access memory (RAM). Some features of microprocessors are; Page 30 of 157 VER: 04.

[Audio]  Registers     Bus         Clock         Coprocessor        1. Register Registers are the temporary holding areas within the CPU for data and instructions that are to be processed immediately. 2. Bus A bus is a kind of electronic pathway that connects parts of the CPU with each other and the CPU with other important devices. There are different types of buses (address bus, control bus, data bus) 3. Clock The clock controls how fast all the operations within a CPU take place. While buying a microcomputer system, clock speed is an important measurement to know about. The clock speed, which expressed in (MHz) megahertz or (GHz) gigahertz, indicates how fast a computer processes information. 4. Coprocessor Coprocessor is a part of microprocessor that is subordinate to the CPU and helps it handle data overload and speed up the computer's operations. The best example of a coprocessor is that used for mathematical calculations. Page 31 of 157 VER: 04.

[Audio] CHAPTER FIVE CHAPTER FIVE CHAPTER FIVE CHAPTER FIVE 5 COMPUTER MEMORY COMPUTER MEMORY COMPUTER MEMORY COMPUTER MEMORY AND AND AND AND STORAGE DEVICES STORAGE DEVICES STORAGE DEVICES STORAGE DEVICES OBJECTIVE: When you have completed this chapter, you will be able to know about the Short Answer Questions Q1. What is the basic unit of storage/ what are the other higher units of storage? Q2. What do you understand by Read Only Memory? Q3. What do you mean by Random Access Memory? Describe. Q4. Define backup. Name the various backup storages devices? Q5. Explain the construction and functions of floppy disks. Q6. Write a note on CD-ROM disc and drive. Q7. What do you know about virtual memory? Long Answer Questions Q1. What do you understand by Read Only Memory? Q2. What do you mean by Random Access Memory? Describe. Q3. Define backup. What are the various backup storages devices? Q4. Explain the construction and functions of floppy disks. Q5. Write a note on CD-ROM disc and drive. Q6. Beside the ROM and RAM what are the other Forms of Memory? Q7. What do you know about the magnetic storage explain the functions and structure of hard disk drive? Page 32 of 157 VER: 04.

[Audio] CHAPTER # 5 COMPUTER MEMORY AND STORAGE DEVICES ===========Short Questions and Answers========= Q1. What is the basic unit of storage/ what are the other higher units of storage? The Electronic computer is a digital device which is based on the binary digits 0 and 1. 0 and 1 are represented by low and high voltages of current. All the calculations are performed using binary digits. The storage is also in the form of 0 and 1. Basic unit of storage: (bit) A bit is the basic unit of storage which is represented by 0 or 1. 0 and 1 means low and high voltages of current. Higher units of storage To measure the large amount of data the higher units of a bit are used. The higher units are used according to requirement for memory and storage media the following are the higher units of storage. 4 bits = 1 Nibble 8 bits =1 Byte 1024 Bytes=1 Kilo Byte 1024 Kilo bytes=1 Mega Byte 1024 Mega bytes=1 Giga Byte 1024 Giga bytes=1 Tera Byte 1024 Tera bytes=1 Exa Byte Unit conversion Data can be represented in higher and lower units according to requirement to convert a lower unit value into higher unit value process of division is applied. To convert the higher unit into lower unit process of multiplication is applied. For Example; 256 MB =? Bytes 256*1024*1024= 26843546 Bytes 16 Bytes=? Giga Byte 16/1024*1024*1024 = 1.49*10 Q2. What do you understand by Read Only Memory? Read only Memory is a chip which contains permanently stored data. The contents inside the ROM cannot be changed by the users. Explanation The Read Only Memory is also called firmware means written program inside a chip. ROM is normally built in the mother board. A ROM chip with the name of BIOS (Basic Input Output System) is available on the mother board. Function of BIOS On Every Start-up of computer system the BIOS detects all the input, output , processing ,storage and other devices connected to computer. If there is any problem the BIOS informs about it using display or beeps. Page 33 of 157 VER: 04.

[Audio] Major types of ROM The following are the main principle type of ROM.  PROM (Programmable Read Only Memory).   EPROM (Erasable Programmable Read Only Memory).  EEPROM (Electronically Erasable Programmable Read Only Memory) Q3. What do you mean by Random Access Memory? Describe. Random Access Memory is the primary storage. It holds data temporarily. It means that it is a volatile memory. The data can reside in this memory until the current is provided to it. Explanation RAM consists of silicon chips in the form of the small circuit board attached on the mother board. The circuit board is called SIMM,DIMM or DDR plugged into the RAM socket. The data and instruction currently being processed are carried by RAM. Types of RAM Chips The following are the main RAM chip types: 1. DRAM (Dynamic Random Access Memory) 2. SRAM (Static Random Access Memory) 3. EDORAM (Extended Data Out Random Access Memory) The above types are different from each other regarding their size, type and bus speed. Q4. Define backup. Name the various backup storages devices? Backup Backup refers to making a copy of data or software to be used in case of failure. Explanation In all business and technical organizations, the data is life blood, data is the most expensive thing for the organization. Data is normally stored on the hard drives for different users, but there is a need of making a copy of data, so that it can be used in case of any technical or natural disaster. The process is called backing up data. Backup devices A device which is used to make backup for the current data is called backup storage device. The following are the backup devices used today: Magnetic storage device Floppy disks Hard disks Magnetic tapes Optical storage devices CD-R CD-RW DVD-R Q5. Explain the construction and functions of floppy disks. A floppy disk, also called a disk or diskette, is a removable storage disk used for storing data. The data on a floppy disk is recorded as magnetic spots. Magnetic spots are known as TRACKS. These tracks are formed as concentric circle on the surface of disk. Tracks are further divided into Page 34 of 157 VER: 04.

[Audio] some sectors for better accessing of data. The disk is made of a special plastic (Mylar) coated with ferrous oxide. Types of Floppy Disk and their Parts The following Table shows the number of tracks and sectors on floppy disks of standard sizes and capacities used today. FLOPPY SIDES DISK TRACKS SECTORS DISK SIZE CAPACITY PER SIDE PER TRACK 51/4 INCH 2 360 KB 40 9 51/4 INCH 2 1.2 MB 80 15 31/2 INCH 2 720 KB 80 9 31/2 INCH 2 1.44 MB 80 18 31/2 INCH 2 2.88 MB 80 36 Q6. Write a note on CD-ROM disc and drive. CD-ROM Disc and CD-ROM Drive CD-ROM, which stands for compact disk-read-only memory, is an opticaldisk format that is used to hold prerecorded text, graphics, sound and videos. Data on disk is imprinted by the disk manufacturer and cannot be altered or erased by the user. Read-only means that data can be retrieved but not altered or erased by the user. This type of optical disk is used to store huge volume of data that rarely change. Q7. What do you know about virtual memory? Virtual memory, or virtual storage, is a condition in which part of a program is stored on disk and is brought into memory only as needed. This feature, which requires special software, uses the disk as an extension of RAM. The virtual-memory program puts as many pieces of the program into RAM as possible. It runs them while putting the remaining pieces on disk, which are retrieved as appropriate. For example, a microcomputer that has only 2 MB of RAM can run a 4 MB program (or even up to 1 GB) by using virtual memory. ===========Long Questions and Answers========= Q1. What do you understand by Read Only Memory? Read only Memory is a chip which contains permanently stored data. The contents inside the ROM cannot be changed by the users. Explanation The Read Only Memory is also called firmware means written program inside a chip. ROM is normally built in the mother board. A ROM chip with the name of BIOS (Basic Input Output System) is available on the mother board. Read-Only Memory or ROM is an integrated-circuit memory chip that contains configuration data. ROM is commonly called firmware because its programming is fully embedded into the ROM chip. As such, ROM is a hardware and software in one. Read-only memory (ROM) is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware (software that is very closely tied to specific hardware, and unlikely to need frequent updates). Page 35 of 157 VER: 04.

[Audio] In its strictest sense, ROM refers only to mask ROM (the oldest type of solid state ROM), which is fabricated with the desired data permanently stored in it, and thus can never be modified. Despite the simplicity, speed and economies of scale of mask ROM, field-programmability often make reprogrammable memories more flexible and inexpensive. Function of BIOS On Every Start-up of computer system the BIOS detects all the input ,output ,processing ,storage and other devices connected to computer. If there is any problem the BIOS informs about it using display or beeps. Major Types Of ROM The following are the main principle type of ROM.  Programmable Read-Only Memory (PROM), or one-time programmable ROM (OTP), can be written to or programmed via a special device called a PROM programmer. Typically, this device uses high voltages to permanently destroy or create internal links within the chip. Consequently, a PROM can only be programmed once.  Erasable Programmable Read-Only Memory (EPROM) can be erased by exposure to strong ultraviolet light (typically for 10 minutes or longer), then rewritten with a process that again needs higher than usual voltage applied.  Electrically Erasable Programmable Read-Only Memory (EEPROM) is based on a similar semiconductor structure to EPROM, but allows its entire contents (or selected banks) to be electrically erased, then rewritten electrically, so that they need not be removed from the computer (or camera, MP3 player, etc.). Writing or flashing an EEPROM is much slower (milliseconds per bit) than reading from a ROM or writing to a RAM (nanoseconds in both cases). Q2. What do you mean by Random Access Memory? Describe. Random Access Memory is the primary storage. It holds data temporarily. It means that it is a volatile memory. The data can reside in this memory until the current is provided to it. Explanation RAM consists of silicon chips in the form of the small circuit board attached on the mother board. The circuit board is called SIMM,DIMM or DDR plugged into the RAM socket. The data and instruction currently being processed are carried by RAM. Types of RAM Chips The following are the main RAM chip types: Dynamic RAM (DRAM) DRAM is a classic form of RAM and has since been replaced by the faster and less expensive SDRAM. DRAM stores data electrically in a storage cell and refreshes the storage cell every few milliseconds. Extended Data-Out RAM (EDO RAM) EDO RAM is faster than DRAM. EDO RAM has also been replaced by SDRAM. EDO RAM is an improvement on DRAM because it has advanced Page 36 of 157 VER: 04.

[Audio] timing features. EDO extends the amount of time data is stored and has a reduced refresh rate. This alleviates the CPU and RAM from timing constraints and improves performance. Synchronous DRAM (SDRAM) SDRAM replaced DRAM, and EDO. SDRAM is an improvement because it synchronizes data transfer between the CPU and memory. SDRAM allows the CPU to process data while another process is being queued. Figure shows an SDRAM. Q3. What do you understand by secondary storage? What are the various secondary storages devices? Secondary Storage Secondary storage refers to saving data or software permanently to be used in present and future whenever required.  Explanation In all business and technical organizations, the data is life blood, data is the most expensive thing for the organization. The secondary storage provides computer the means of storage large quantities of data for longer periods of time. The secondary storage is also called auxiliary storage or external memory. The secondary storage is non volatile, means it does not require current to maintain data in the storage device. Secondary Storage Device A device which is used to make backup for the current data is called secondary storage device.  Explanation Various types of secondary storage devices are used to take backup of the data. These are as follows: Magnetic storage device Floppy disks Hard disks Magnetic tapes Optical storage devices CD-R CD-RW DVD-R Procedure of backing up data For all the business and technical organization it is necessary to take backup of data periodically, means on monthly, weakly or daily bases. In most of the organizations a node (computer system) is installed as backup server in the local area network which uses large capacity hard drive to take backup. Backup Software A number of softwares are available in the market by different venders to take backup of data. Mostly backup softwares are building are built in the operating system being used. Page 37 of 157 VER: 04.

[Audio] Q4. Explain the construction and functions of floppy disks. A floppy disk, also called a disk or diskette, is a removable storage disk used for storing data. The data on a floppy disk is recorded as magnetic spots. Magnetic spots are known as TRACKS. These tracks are formed as concentric circle on the surface of disk. Tracks are further divided into some sectors for better accessing of data. The disk is made of a special plastic (Mylar) coated with ferrous oxide. Types of Floppy Disk and their Parts The following Table shows the number of tracks and sectors on floppy disks of standard sizes and capacities. FLOPPY SIDES DISK TRACKS SECTORS DISK SIZE CAPACITY PER SIDE PER TRACK 51/4 INCH 2 360 KB 40 9 51/4 INCH 2 1.2 MB 80 15 31/2 INCH 2 720 KB 80 9 31/2 INCH 2 1.44 MB 80 18 31/2 INCH 2 2.88 MB 80 36  Tracks  Data is recorded in the form of magnetics are known as TRACKS. These tracks are formed as concentric circle on the surface of disk.   Sectors  Each track on a disk is divided into pie-wedge-shaped sections known as sectors. These sectors are used by the computer system for storage reference purposes. Disks are identified as being either soft-sectored or hard-sectored.   Sides  The early disks were either single-sided or double-sided. A singlesided stores data on one side only. A double-sided disk stores data on both sides. The standard 3½ -inch floppy disks are double-sided, holding twice the data.   Densities  Floppy disks may be double density, high density, or extra-high density. Density here means recording density, the number of bits per inch (bpi) of data that can be written onto the surface of a disk. Q5. Write a note on CD-ROM disc and drive. CD-ROM Disc and CD-ROM Drive CD-ROM, which stands for compact disk-read-only memory, is an opticaldisk format that is used to hold prerecorded text, graphics, sound and videos. Data on disk is imprinted by the disk manufacturer and cannot be altered or erased by the user. Read-only means that data can be retrieved but not altered or erased by the user. This type of optical disk is used to store huge volume of data that rarely change. Page 38 of 157 VER: 04.

[Audio] Media Disc construction Optical media and magnetic media have some similarities and some differences. Magnetic media are spelled with a "k" , disk. Optical media are spelled with a "c" , disc.  CD-ROM discs use a laser light and optical lenses to read information from the disc.   A microscopic look will show you pits and lands. Pits are always the of same depth and width but varies in length.   Magnetic disks rotate at a constant angular velocity, where as CDROM uses a method called constant linear velocity, that avoids the waste of storage space.   CD-ROM discs have spiral tracks with sectors of equal length. To be able to read data on a CD, data must pass the read laser at a constant linear speed.   For a 8x CD-ROM the required speed is 1.3 meters/sec. To accomplish this, the disc RPM must be adjusted continuously. The RPM of the disc changes from 500 RPM at the center to 200 RPM at the outer edge.   By using a constant linear velocity method, a CD can contain more sectors and ultimately more data.   A disc is 12 cm in diameter and slightly more than 1 cm in thickness.   It is made of a clear polycarbonate, a thin layer of Aluminum and lacquer protective layer. Page 39 of 157 VER: 04.

[Audio] Reading Information from CD A red laser, with a wavelength of 790 nanometers, is used in CD-ROM drives. Laser light has a single wavelength and coherent in phase (polarized). The red light hits the land reflects back and reaches the photodiode by reflecting at 90 degree by the prism, where it creates higher voltages. Where as the pits scatter the light, some are reflected back but not in its full intensity, creates lower voltages in the photodiode. Capacity of the CD  650 MB data or 74 min Audio = 464 floppy disks 3.5"  Digitized information Q6. Beside the ROM and RAM what are the other Forms of Memory? The performance of microcomputer can be enhanced further by adding other forms of memory, as follows.  Cache Memory It is more expensive and faster than RAM but slower and less expensive than registers. It is used to increase the speed of processing by making current programs and data available to CPU at rapid rate. The general principle is to keep frequently accessed data in the faster cache while less frequently used items should be kept in RAM.  Virtual memory Virtual memory, or virtual storage, is a condition in which part of a program is stored on disk and is brought into memory only as needed. Page 40 of 157 VER: 04.

[Audio] This feature, which requires special software, uses the disk as an extension of RAM. The virtual-memory program puts as many pieces of the program into RAM as possible. It runs them while putting the remaining pieces on disk, which are retrieved as appropriate. For example, a microcomputer that has only 2 MB of RAM can run a 4 MB program (or even up to 1 GB) by using virtual memory.  Video Memory Video memory or video RAM (VRAM) chips are used to store display images for the monitor. The amount of video memory determines how fast images appear and how many colors are available. Video memory chips are particularly desirable if you are running programs that display a lot of graphics.  Flash Memory Flash memory, or flash RAM, cards consist of circuitry on credit-cardsize cards that can be inserted into slots connected to the motherboard. Unlike standard RAM chips, flash memory is non-volatile. That is, it retains data even when the power is turned off. Flash memory can be used not only to simulate main memory but also to supplement or replace hard disk drives for permanent storage. Q7. What do you know about the magnetic storage explain the functions and structure of hard disk drive? Magnetic storage In magnetic storage data is stored on the platters having a coating of metal oxide. Reading and writing of data is done through electromagnetic mechanism. Page 41 of 157 VER: 04.

[Audio] Hard disk A hard disk is a basic storage device which works on electro magnetic mechanism. Explanation In the hard disk storage media the disk and drive are integrated. Hard disk can store huge amount of data. Structure A hard disk consists of aluminum platters having metallic oxide coating. The platters can move around a spindle. A read-write head can read and write data in the form of bits. By formatting a hard drive sectors and tracks are created on the disk which makes it possible for reading and writing of data. A hard disk platter (or disk) is a component of a hard disk drive: it is the circular disk on which the magnetic data is stored. The rigid nature of the platters in a hard drive is what gives them their name (as opposed to the flexible materials which are used to make floppy disk). Hard drives typically have several platters which are mounted on the same spindle. A platter can store information on both sides, requiring two heads per platter. Hard Disk Controller One side of the first platter has space reserved for hardware-based trackpositioning information which is not available to the operating system. This data is written to the disk during assembly and is used by the disk controller to position the drive heads correctly. Motherboard Connectivity A hard drive contains a power and data connector. A Molex connector of 12 volt DC provides current from power supply to hard drive. The data connectivity to the motherboard can be: 1. IDE (Integrated Drive Electronics) 2. EIDE (Enhanced Integrated Drive Electronics) 3. SATA (Serial Advanced Technology Attachments) Page 42 of 157 VER: 04.

[Audio] CHAPTER SIX CHAPTER SIX CHAPTER SIX CHAPTER SIX 6 SOFTWARE SOFTWARE SOFTWARE SOFTWARE OBJECTIVE: When you have completed this chapter, you will be able to know about the Short Answer Questions Q1. Define software. What are the two main categories of software? Q2. Define operating system. What are the famous Operating Systems used now a days? Q3. Define operating Systems. What are the key functions of an operating system? Q4. Write a short note on Microsoft Disk Operating System. Q5. Write a short note on Microsoft Windows Operating System. Q6. Write a short note on UNIX Operating System. Q7. Define user interface. How many types of operating systems are there regarding user interface? Q8. What do you know about boot up process? Q9. Define computer language. Why computer languages are used? Give example. Q10. Name the different generations of programming languages. Q11. Define Language Translators. How many types of language translators are there? Long Answer Questions Q1. Define Software. What are the major types of software? Mention software examples. Q2. Explain Operating Systems. What are the key functions of an operating system? Q3. Define Language Translators. How many types of language translators are there? Explain. Q4. What are operating system types? Explain in detail. Q5. Explain different generations of programming languages. Page 43 of 157 VER: 04.