Computer for Class IX Guide

COMPUTER FOR CLASS IX
Ahtisham Ali Shah
ADDULLAH EDUCATIONAL SOCIETY 110/2, GULBAHAR NO. 2 KARACHI 18
E-mail: ahtishamm@hotmail.com
www.facebook.com/aes.pk
www.notes09.blogspot.com
Cell: +92 333 3102680

110/2. Gulbahar No. 2, (400 Quarters), Karachi 18 Page 1 of 50
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CHAPTER ONE .................................................................................................................................................................... 4
INTRODUCTION TO COMPUTER ........................................................................................................................ 4
Q - 1) DEFINE THE TERM COMPUTER? OR DEFINE COMPUTER? ...................................................................................... 4
Q - 2) DEFINE HARDWARE AND SOFTWARE? .................................................................................................................. 4
Q - 3) STATE TYPES OF COMPUTER OR CLASSIFICATION OF COMPUTER: ........................................................................ 4
Q - 4) STATE TYPES OF COMPUTER ACCORDING TO PURPOSE: ....................................................................................... 4
Q - 5) WHAT IS THE CONCEPT SOURCE AND OBJECT PROGRAM (CODE)? ....................................................................... 4
Q - 6) STATE TYPES OF COMPUTER ACCORDING TO CAPACITY: OR SHORT NOTE? .......................................................... 5
Q - 7) WHAT ARE THE CAPABILITIES AND LIMITATIONS OF A COMPUTER? ..................................................................... 5
Q - 8) DEFINE A PROGRAMMING LANGUAGE AND STATE ITS TYPE BRIEFLY: .................................................................. 6
Q - 9) STATE TYPES OF COMPUTER ACCORDING TO DATA HANDLING: ........................................................................... 6
Q - 10) WRITE SOME DRAWBACKS OF INTERNET? ............................................................................................................ 7
Q - 12) WHAT ARE LANGUAGE TRANSLATORS? EXPLAIN EACH OF THEM: ........................................................................ 7
Q - 13) DESCRIBE AGES OF COMPUTER: ............................................................................................................................ 8
Q - 14) DESCRIBE THE FOLLOWING DEVICES WITH THEIR INVENTORS: ............................................................................. 8
Q - 15) WRITE IMPACT OF COMPUTER ON SOCIETY: ......................................................................................................... 9
Q - 16) WRITE MAIN CHARACTERISTIC OF 1ST, 2ND, 3RD,4TH AND 5TH GENERATIONS: ....................................................... 10
Q - 17) DIFFERENTIATE THE FOLLOWING: ....................................................................................................................... 11
CHAPTER TWO ................................................................................................................................................................. 13
COMPUTER COMPONENTS ................................................................................................................................. 13
Q - 1) DEFINE CPU? AND WRITE ITS FUNCTIONS: ............................................................................................................ 13
Q - 2) DEFINE CPU AND WHAT ARE THE MAIN UNITS OF A CPU? EXPLAIN EACH OF THEM WITH THE HELP OF A BLOCK DIAGRAM? ........................................................................................................................................................................... 13
Q - 3) DEFINE BUS IN GENERAL? WHAT ARE THE PURPOSE OF ADDRESS BUS, DATA BUS AND CONTROL BUS? ............ 14
Q - 4) WHAT ARE I/O DEVICES? OR WRITE MAJOR FUNCTIONS OF INPUT/OUTPUT DEVICES: ...................................... 14
Q - 5) DEFINE MEMORY STORAGE AND COMPARE AND CONTRAST INTERNAL AND EXTERNAL MEMORY: ................... 15
Q - 6) DEFINE PORT AND GIVES ITS TYPES: .................................................................................................................... 15
Q - 7) DEFINE REGISTER? HOW MANY REGISTER ARE THERE? ....................................................................................... 16
Q - 8) WHAT IS THE PURPOSE OF MAIN MEMORY? ...................................................................................................... 16
Q - 9) DIFFERENTIATE RAM AND ROM, SERIAL PORT AND PARALLEL PORT: ................................................................. 16
CHAPTER THREE ............................................................................................................................................................ 17
INPUT OUT PUT DEVICES ..................................................................................................................................... 17
Q - 1) WHAT ARE INPUT AND OUTPUT DEVICES: .......................................................................................................... 17
Q - 2) DEFINE KEYBOARD AND STATE ITS DIVISION: ..................................................................................................... 17
Q - 3) WHAT IS THE USE OF CURSOR CONTROL/MOMENT KEY IN A KEYBOARD? ......................................................... 17 Contents

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Q - 4) WHAT IS THE DIFFERENCE BETWEEN SOFTCOPY AND HARDCOPY? ..................................................................... 18
Q - 5) DEFINE MONITOR AND STATE ITS TYPES: BRIEFLY ............................................................................................... 18
Q - 6) DEFINE PRINTER AND STATE ITS TYPES: .............................................................................................................. 19
Q - 7) DEFINE PLOTTERS AND STATE ITS TYPES: ............................................................................................................ 19
Q - 8) DEFINE SCANNER AND STATE ITS TYPES: OR WRITE PURPOSE OF IT: .................................................................. 20
Q - 9) WHICH DEVICE IS USED AS INPUT DEVICE AS WELL AS OUTPUT DEVICE? ............................................................ 20
Q - 10) DEFINE AN INPUT DEVICE & DESCRIBE MOUSE OR LIGHT PEN: ........................................................................... 21
Q - 11) DEFINE JOYSTICK, MICROPHONE AND DIGITAL CAMERA: ................................................................................... 21
Q - 12) DEFINE DUAL PURPOSE DEVICE. ALSO DESCRIBE DISK DRIVE AND CD-WRITER? ................................................ 22
Q - 13) DEFINE MOTHERBOARD: ..................................................................................................................................... 22
Q - 14) DEFINE USB: ........................................................................................................................................................ 22
CHAPTER FOUR .............................................................................................................................................................. 23
STORAGE DEVICES .................................................................................................................................................. 23
Q - 1) DEFINE MEMORY OR MEMORY STORAGE: .......................................................................................................... 23
Q - 2) DEFINE RAM AND ROM? ..................................................................................................................................... 23
Q - 3) DEFINE VARIOUS TYPES OF ROM? ....................................................................................................................... 23
Q - 4) WHAT IS THE DIFFERENCE BETWEEN STATIC RAM AND DYNAMIC RAM? ............................................................ 24
Q - 5) WHAT IS THE DIFFERENCE BETWEEN SIMM AND DIMM? .................................................................................... 24
Q - 6) DEFINE BACKING OR SECONDRY MEMORY/STORAGE? AND DESCRIBE ANY TWO OF THEM: .............................. 24
CHAPTER FIVE ................................................................................................................................................................. 26
DATA REPRESENTATION ..................................................................................................................................... 26
Q - 1) DEFINE DATA AND BRIEFLY STATE ITS KIND: ....................................................................................................... 26
Q - 2) WHAT IS NUMBER SYSTEM? HOW MANY TYPES OF NUMBER SYSTEM ARE THERE? ........................................... 27
Q - 3) DEFINE CODES AND HOW MANY TYPES ARE USED IN COMPUTER SYSTEM? ....................................................... 27
Q - 4) WHICH NUMBER SYSTEM COMPUTER USES FOR PROCESSING OF DATA & WHY? ............................................... 28
Q - 5) HOW MANY TYPES OF CODING SCHEMES ARE USED IN COMPUTER SYSTEM? OR DEFINE THE VARIOUS CODING SCHEMES USED IN THE COMPUTER SYSTEM? ...................................................................................................................... 28
CHAPTER SIX ................................................................................................................................................................... 29
BOOLEAN ALGEBRA ................................................................................................................................................ 29
Q - 1) WHAT IS BOOLEAN ALGEBRA? OR DEFINE BOOLEAN ALGEBRA........................................................................... 29
Q - 2) WHAT ARE THE LAWS OF BOOLEAN ALGEBRA? STATE THEIR VARIOUS TYPES: ................................................... 29
Q - 3) WHAT ARE THE LOGICAL OPERATORS OF BOOLEAN ALGEBRA: ........................................................................... 29
Q - 4) DEFINE BOOLEAN EXPRESSION AND BOOLEAN FUNCTION: ................................................................................ 30
Q - 5) WHAT ARE THE RULES OF BOOLEAN ALGEBRA: ................................................................................................... 30
Q - 6) DEFINE THE FOLLOWING TERMS: ........................................................................................................................ 31
Q - 7) STATE AND PROVE THE DE-MORGAN'S THEOREMS: ........................................................................................... 31

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Q - 8) WHAT ARE THE STANDARD FORMS OF BOOLEAN EXPRESSION: ......................................................................... 32
Q - 9) WHAT IS KARNAUGH MAP? HOW CAN KARNAUGH MAP HELP IN SIMPLIFYING A BOOLEAN EXPRESSION? ....... 32
CHAPTER SEVEN ............................................................................................................................................................. 33
COMPUTER SOFTWARE ........................................................................................................................................ 33
Q - 1) WHAT IS SOFTWARE? DESCRIBES VARIOUS TYPES OF SOFTWARE: ..................................................................... 33
Q - 2) WHAT IS AN OPERATING SYSTEM? ..................................................................................................................... 34
Q - 3) WHAT ARE LANGUAGE TRANSLATORS? DEFINE EACH: ........................................................................................ 34
Q - 4) WHAT ARE CHARACTERISTICS OF DISK OPERATING SYSTEM (DOS)? ................................................................... 34
Q - 5) WHAT ARE THE TYPES OF DOS COMMANDS: ...................................................................................................... 35
Q - 6) WHAT ARE WILDCARD CHARACTERS? WHY ARE THEY USED? ............................................................................. 35
Q - 7) WHAT IS DIRECTORY? AND WHAT DOS COMMANDS ARE USED TO CREATE, CHANGE OR DELETE DIRECTORY: .. 35
Q - 8) WHAT IS THE DIFFERENCE BETWEEN DOS AND WINDOWS OPERATING SYSTEM? OR DISTINGUISH BETWEEN DOS AND WINDOWS OPERATING SYSTEM: ................................................................................................................................. 36
CHAPTER EIGHT ............................................................................................................................................................. 37
INTRODUCTION TO WINDOWS OPERATING SYSTEM ..................................................................... 37
Q - 1) DEFINE OR WHAT IS DESKTOP? WHAT ARE ITS ELEMENTS? ................................................................................ 37
Q - 2) EXPLAIN THE FUNCTIONS OF WINDOWS EXPLORER? .......................................................................................... 38
Q - 3) HOW CAN YOU SEARCH A FILE AND FOLDER? ..................................................................................................... 38
Q - 4) HOW CAN YOU INSTALL A PRINTER? ................................................................................................................... 38
Q - 5) HOW CAN YOU CHANGE WALLPAPER OF THE DESKTOP? .................................................................................... 38
Q - 6) WHAT IS THE PROCEDURE OF SETTING A SCREEN SAVER? .................................................................................. 39
Q - 7) WHAT IS THE FUNCTION OF START BUTTON? ..................................................................................................... 39
Q - 8) WHAT IS A COMPUTER VIRUS? HOW A VIRUS IS REMOVED FROM DISK? ........................................................... 39
Q - 9) WHAT DO MEAN BY FILE AND FOLDER? .............................................................................................................. 39
Q - 10) WHAT IS THE FUNCTION OF CONTROL PANEL? AND DEFINE EACH ITEM OF CONTROL PANEL: OR WRITE A SHORT NOTE ON CONTROL PANEL: ................................................................................................................................................. 40
Q - 11) WRITE A SHORT NOTE ON RECYCLE BIN: ............................................................................................................. 41
Q - 12) WHAT IS THE INSTALLATION PROCEDURE OF WINDOWS? .................................................................................. 41
Q - 13) DIFFERENTIATE BETWEEN THE FOLLOWING: ....................................................................................................... 41
Glossary .............................................................................................................................................. 43

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Q - 1) Define the term computer? Or Define computer?
Ans: Computer is an electronic and automatic device that accepts data and instruction (In form of program) as Input, processes it, and produces the results or information as Output. It has also capability to plug and play different devices.
Q - 2) Define Hardware and Software? Hardware:
The physical and tangible components forming a computer are called “Hardware”. It includes not only the computer system but also cables, connectors, power supply units and peripherals such as Keyboard, Mouse, Audio Speaker, Printer etc. Software:
The software refers to the program that instructs the computer what to do. Alternatively, the term Software refers to non – physical elements of a computer system. Software makes the hardware usable. Such as Ms. Office, Corel Draw, Oracle etc.
Q - 3) State types of computer or classification of computer:
Computer is classified according to purpose, type of data handled and capacity.
Purpose: Whether it is general purpose or special purpose.
Data handled: Whether it is using analog or digital data or combination of both.
Capacity: Whether the volume of work that it can handle, is large or small.
Q - 4) State types of computer according to purpose:
Ans: There are two types of computer according to purpose General and Special purpose.
General purpose:
These computers are designed to handle a variety of different problems and to meet different needs such as Payroll, Account, and Inventory Control etc.
Special purpose:
These computers are designed to handle specific problems and perform specific tasks. Such as: Satellite Tracking, Air Traffic Control and Industrial Process Control etc.
Q - 5) What is the concept source and object program (code)?
Source program (code):
Object program (code):
Chapter one
INTRODUCTION TO COMPUTER

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Q - 6) State types of computer according to capacity: Or short note?
Ans:
Super computers:
Super computers are the largest, sophisticated and fastest machines are designed to perform complex numerical computations at the speeds of up to 50 million operations per second.
These computers are used to model very large dynamic systems.
Such as Weather Patterns, Satellite Tracking, Cold Testing of Atomic and Nuclear Weapons etc.
Mainframe computers: (Large Scale Computer)
Mainframe computers are the most productive general-purpose system. These computers serve hundreds of terminals all at same time these computers are essentials of big organizations. Such as Banks, Airlines, and Government to keep Tracks of their Citizens.
Minicomputers:
Minicomputers are increasingly powerful and do almost anything that large computers do; these are slower and much lower cost than mainframe. These are ideal for small companies and organizations.
A minicomputer is a multiprocessing system having terminals attached in it and capable of supporting 4 to 200 users at once.
DEC VAX & IBM AS/400 are commonly used Minicomputers.
Microcomputers:
Microcomputers are computers powered by microprocessors. Sometimes they are referred as Single – Chip processor or system-on-a- chip.
Microcomputer or personal computers are smallest computers, designed to be used by Individuals for Writing, Playing Games, Illustrating, Communicating etc.
Q - 7) What are the Capabilities and Limitations of a computer?
Capabilities of Computer:
Limitations of Computer:

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Q - 8) Define a programming language and state its type briefly: Programming language:
A set of rules that provides a way of telling a computer what operations is to perform, is called Programming language. It is categorized into three types as under. Machine language: (Low Level Language)
Computer has its own unique machine language to perform specific tasks. It is based on binary codes 0s and 1s to execute given instructions. All instructions in machine language consist of series of 0s and 1s. It is very difficult to write program in machine language. Assembly language: (Low Level Language)
Each computer has its own unique assembly language. In this language, the statements are written in symbolic code (Mnemonics) that are easier for human to read and write Such as A for Add and L for Load. The main reason for writing assembly language program is efficiency and produce faster program. High Level Language: (Related Human language)
High-level languages are closer to human language than low-level language, and include statements like Go to and Print, which are regular words. There are various high level languages such as FORTORN, PASCAL, COBAL etc.
Q - 9) State types of computer according to data handling:
Ans:
Analog computers:
These computers use analog method to process data. These computer operate on numbers represented by directly measurable quantities which vary nonstop. EC – 1 and Vannevar Bush's Differential Analyzer are examples of these computers.
Digital computers:
These computers handle discrete values (0 or 1) or real numbers. These computers are specialized in counting. All commonly used computers are Digital.
Hybrid computers:
These computers are the combination of digital and analog computers system. These computer use analog to digital and digital to analog conversion, and may input or output both. These computers use in special areas such as Space Vehicle Simulations, Training of Astronauts and in Robotics.

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Q - 10) Write some drawbacks of internet? Drawbacks/Demerits or disadvantage of Internet:
Q - 11) Write some advantages of internet? Merits or Advantage of Internet:
Q - 12) What are language translators? Explain each of them:
Ans: These are the programs, which are used to convert source program to object program. These are in three types Assembler, Compiler and Interpreter.
Assembler:
It a program that converts or translates an assembly language program into machine language.
Compiler:
Compiler is similar to assembler in a way that it translates the high-level language program into machine language and creates an object file too.
Interpreter:
Interpreter is also used to translate high-level language program into machine language but it translates the program whenever it is executed.

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Q - 13) Describe ages of computer:
Ans: Computer is classified into three ages Dark Age, Middle age and Modern age.
Dark Age: (3000 BC – 1890 AD)
In Dark Age, the computers were only used for Calculation Purpose that had capability to store as well. These computers were often very large and weird shapes.
Such as Abacus, Napier's bones, Slide Rule, Pascaline, Leibniz calculator, Airthometer etc.
Middle age: (1890 AD – 1940AD)
In middle age, computers' technology was changed and Binary system of Algebra was introduced. Storage capacity increased and electronic computers were developed.
Such as Vannevar Calculator, Hollerith's tabulating machine, IBM and other electronics computers etc.
Modern age: (1940 – Beyond)
In modern age computers’ technology and ideology has been improved and computer were categorized in Five Generations. Each generations of computer is categorized by major technological development that fundamentally changed.
Q - 14) Describe the following devices with their inventors:
Abacus:
The ABACUS was invented about 5000 years ago in Asia Minor and still in use today, is considered as first computer. This device allows users to make computations using a system of sliding beads arranged on a rack. Early merchant used it to keep trading transactions.
Leibniz Calculator:
In 1694, A German mathematician and philosopher, Gottfried Wilhelm Von Leibniz improved Pascaline by creating a machine that could also multiply. His machine works by a system of gears and dials
Airthometer:
In 1820, A Frenchman, Charles Xavier Thomas de Colmar invented a machine that could perform the four basic arithmetic operations. He named his machine Airthometer, presented a more practical approach to computing because it could add, subtract, multiply and divide.

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Napier Bones:
In 1612, John Napier invented logarithms and many other machines for multiplication. However, best known of his machines was the “Bone” or “Napier Bones.” This device consist a set of eleven bones or rods with numbers marked on them. By placing rods, side-by-side products & quotients of large values can obtain very easily.
Pascaline: (Pascal’s Calculator)
In 1642, Blasé Pascal, invented the first operating model, what he called a numerical wheel calculator and called a Pascaline. It consists of eight movable dials to add numbers up to eight figures long. It is used a base of ten to accomplish this. This device could only add and subtract, while multiplication and division operations were implemented.
Babbage’s Difference Engine:
In 1822, Babbage proposed a machine to perform differential equations, called a Difference Engine. Powered by steam and large as a locomotive, it would have a stored program and could perform calculations, print the result automatically.
Hollerith’s Tabulating Machine:
In 1889, an American inventor, Herman Hollerith also applied the Jacquard loom’s concept to computing and introduced his Tabulating Machine. His machine sensed the holes in punched cards, triggering a wire to pass through the holes closing an electrical circuit. Finally, input initiated mechanical counters.
Slid Rule:
In 1622, ought red created the slid rule (originally circular in shape) is based on Napier’s logarithms. A slide rule consists of two movable rulers placed side by side. Each ruler is marked off and proportional to the logarithms of numbers printed on the ruler. By sliding the rulers’ one can multiply and divide.
Q - 15) Write impact of computer on society:
Ans: The impact of computer on society as under: Upside:
 Makes work process faster and maintains massive amount of data.
 Creates new jobs and increases productivity through flexible scheduling.
 Reduces workforce cost through telecommuting. Down side:
 Automation replaces or deskills worker and constant intrusive employee.
 Computers replaced more jobs than they create.
 Personal data used for purpose other than intended.

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Q - 16) Write main characteristic of 1st, 2nd, 3rd,4th and 5th generations:
1st Generation main Features/Characteristic:
2nd Generation main Features/Characteristic:
3rd Generation main Features/Characteristic:
4th Generation main Features/Characteristic:
5th Generation main Features/Characteristic:

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Generation Table
1st
2nd
3rd
4th
5th
Period
1940 - 1956
1956 – 1963
1964 - 1971
1971 – 1984
1984 - Beyond
Technology
Vacuum Tube
Transistors
ICs
Microprocessor
Artificial Intelligence
Language
Machine
Very complicated
Machine & Assembly
Much Easier
High Level
COBOL, FORTRAN, PASCAL
Database Control
ORACLE, FOXPRO, SQL
Natural
As
Human speech
Mode of use
Batch
Batch
SSI
VLSI
SVLSI & ULSI
Memory
1 – 4k
4 – 32k
32 – 1000k
1000 – 4000k
4000k – more
Input/output
Punch card
Magnetic tape
Keyboard, Magnetic Disk
Keyboard, Disk and other
Mouse, Remote etc.
Storage Data
Punch card
Magnetic tape
Magnetic tape
Disk & other
Permanent , USB
Q - 17) Differentiate the following:
Analog computer
Digital computer
Compiler
Interpreter
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Low level language
High level Language








Hardware
Software








System Software
Application Software







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Q - 1) Define CPU? and Write its functions:
CPU stands for central processing unit; it is the brain of computer that controls all processing of the computer system. It has two major parts (ALU) Arithmetic Logic Unit and Control Unit (CU).
Functions of CPU:
Interprets the data and instructions.
Generates control signals and produces address bits needed by memory.
Perform arithmetic and logic operations.
Q - 2) Define CPU and what are the main units of a CPU? Explain each of them with the help of a block diagram?
C.P.U (Central Processing Unit):
CPU (Central Processing Unit) is the brain of computer that controls all processing of the computer system. It has two main units (1) Arithmetic and Logic Unit (ALU) and (2) Control Unit (CU)
Arithmetic Logic Unit (ALU):
ALU is the part of CPU where basic function such as additions, subtractions, multiplication, division and logical operations are performed. It includes registers that are high speed and volatile memory separate from main memory (RAM).
Control Unit (CU)
CU is also the part of CPU. That works like a traffic cop directing the flow of data between the components of the CPU. It controls input/output devices and data transfer process nonstop from memory. BLOCK DIAGRAM OF C.P.U (COMPUTER SYSTEM)
FLOW OF DATA
FLOW OF INSTRUCTIONS
FLOW OF CONTROL
Chapter two
COMPUTER COMPONENTS

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Q - 3) Define Bus in general? What are the purpose of Address Bus, Data Bus and control Bus?
Bus:The set of wires that connects different components together is called Bus. It controls flow of signals in the computer. There are three type of bus Address Bus, Data Bus and Control Bus.
Address Bus:It is a collection of wires connecting the CPU with main memory in order to identify the particular address in main memory where data is stored.
Control Bus:It is a physical connection that carries control information between the CPU and other devices in the computer. Control Bus carries signals that report the status of various devices.
Data Bus:It is a communication route through which data can travel between the computer's central processing unit, memory and peripherals. The speed depends upon number of wires in the bus.
Q - 4) What are I/O devices? Or write major functions of input/output devices:
I/O Devices:
I/O (Input/Output) pronounced as "eye – oh", describes a device that introduces data into and extracts data from systems. Typical I/O devices are Printer, Keyboard, Mouse, Light Pen, Scanner etc.
Major Functions of Input Devices:
The major function is to pass information into the memory unit of the CPU and converts into Binary Pattern, which can be held inside the computer memory.
Major Functions of Output Devices:
The major purpose is to convert data and information expressed in electronic impulses to human understandable forms such as Printed Report.

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Q - 5) Define memory storage and compare and contrast internal and external memory: Memory: It is the storage device inside computer where data, information and programs reside. It is in two types. Internal Memory: (Primary Storage or Main Memory)
Internal memory is a set of chips located on motherboard. It is also known as Main Memory or Primary Storage. It can be in both forms temporary and permanent.
Such as Ram (Random Access Memory) and Rom (Read Only Memory). External Memory: (Secondry Storage)
External memory is physical devices serrate from CPU. They are also called Auxiliary Devices. These are slowest and cheapest form of memory. Such as USB, Optical Disks, Floppy Disk, Hard disk, CD – ROM etc.
Q - 6) Define port and gives its types:
Port:
Internally:
Externally:
Serial port:
Parallel port:

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Q - 7) Define Register? How many Register are there?
Register:
It is a type of volatile or temporary memory and it's a part of CPU. Data currently being processed is stored in it. There are fourteen registers.
Q - 8) What is the purpose of main memory?
Ans: The main purpose of Main Memory is to give instant space for storage and hold programs that are currently running in the CPU.
Q - 9) Differentiate RAM and ROM, Serial port and Parallel port:
RAM
ROM
RAM stands for Random Access Memory.
ROM stands for Read Only Memory.
It is volatile and temporary.
It is non-volatile and permanent.
It requires electric current to retain information.
It does not require electric current to retain information.
It loses its contents when computer is turn off.
It never loses its contents even computer is turn off.
Serial port
Parallel port
It is a port or interface used for serial communication.
It is a port or interface used for parallel communication.
It transmits only 1 – bit data at a time.
It transmits 8 or more bits data at once.
It is male connector with 9 or 25 pins.
It is female connector with 25 holes.
It sends data slower but reliable for longer distance transmission.
It sends data faster but unreliable for longer distance transmission.

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Q - 1) What are input and output devices:
Input devices: These are physicals equipment that read or translate data into electronic impulses which can be understood by computer. Such as KEYBOARD, LIGHT PEN, MOUSE, TRACKBALL, DIJITAL CAMERA etc.
Output devices: These are physicals equipment which translates the outcome of computations and related activities carried out in the CPU. Some output devices are Printer, Plotter, and Monitor etc.
Q - 2) Define keyboard and state its division:
Keyboard is the primary input text device. It consists of a set of keys for computer input. The alphabetic key arrangement is same as typewriter that is known as QWERTY. A standard keyboard includes about 100 keys.
The arrangement of keys is divided into five divisions as under:
i) Alphanumeric keypad:
It looks like a typewriter. Along with alphanumeric keys there's some special key such as Caps lock, Back space, Enter etc.
ii) Numeric keypad:
It looks like a calculator consisting numbers 0 to 9, some basic operators (+,*, /, –) Numb Lock and Enter key.
iii) Function keys:
These are at the top of keyboard including F1 to F12; these are used as input command without typing long command. Such F1 for Help and F3 for Search etc.
iv) Screen Navigation or Cursor movement keys:
These key are used to move cursor around the screen. Such as Arrow Key, Home and End, Page up and Page down.
v) Modifier keys:
These keys are used to modify the input of other keys. Such as CRT, Alt, Shift etc.
Q - 3) What is the use of Cursor Control/Moment Key in a keyboard?
Ans: These keys are used to move and control the cursor moment around the screen. These are Arrow keys, Home and End, Page up and Page down.
Chapter Three
INPUT OUT PUT DEVICES

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Q - 4) What is the difference between Softcopy and Hardcopy?
Softcopy:
It refers to the Screen Output that is intangible and temporary. It is also a machine readable form of corresponding hardcopy.
Hardcopy:
It is a term that is used to refer to a print – out on paper which is tangible and permanent.
Q - 5) Define Monitor and state its types: Briefly
Monitor:
Monitor is a T.V like output device. It is a device that displays text and graphics generated by a computer. Monitor's quality depends upon its resolution, bandwidth, refresh rate, dot pitch and convergence. In term of color capabilities all monitors are in three classes.
Monochrome:
This type of monitor displays two colors: Black and White, Green and Black or Amber and Black.
Gray-Scale:
This type of monitor displays only different shades of Gray color.
Color Monitor:
This type of monitor displays 16 to one million different colors. Color monitors are often called RGB (Red – Green – Blue).
There are two basic types of monitor:
i) Crt monitor:
It is similar to the television screen and also works in the same way it uses a large Vacuum tube called cathode ray tube (CRT).
ii) Flat Panel Display or Liquid Crystal Display (LCD):
It has liquid in its panel except Vacuum tube and displays excellent result on the screen.

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Q - 6) Define printer and state its types:
Printer:
It is an output device that transfers information to the paper as result. Printers vary in size, speed, sophistication and cost.
In terms of technology utilized, printer falls into two categories:
i) Impact Printer:
This printer works by striking at ink ribbon. These printers are much noisier than other printers. Such as Daisy wheel, Dot – matrix and Line etc.
ii) Non – Impact Printer:
These printers work by electronic beam passing through the mark containing the various characters and then impinging upon an electronic sensitive film.
Such as Ink - Jet, Laser, Plotter, Thermal Printers etc.
Q - 7) Define plotters and state its types:
Plotter:
It is an output device that prints Drawing, Graphics, Maps, Plotting Engineering drawing and Machine components.
It is changed from printer in that way that it draws continues lines by using a pen.
Plotter has two types:
A) Pen Plotter and B) Electrostatic Plotter.
A) Pen plotters:
They have an ink pen attached to draw images. They are further divided into two types Drum plotter and Flatbed plotter.
i) Drum Plotter:
In this plotter the pen is moved in a single axis track and paper it move on a cylinder drum to add the other axis.
ii) Flatbed Plotter:
In this plotter the pen is moved to draw image and paper is fixed on a flat surface.
B) Electrostatic plotters:
These plotters work similarly to a laser printer and produce faster images but its quality is considered to be poor then pen plotters.

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Q - 8) Define scanner and state its types: or write purpose of it:
Scanner:
Scanner is an input device that reads images and text and converts them into digital signals which can be directly fed and stored in computer. There are three purpose of scanner as under.
Graphical Scanner:
These scanners are used to scan and convert photo or other graphical images into digitals signals for further use.
Text Scanner:
These scanners are used to scan and convert text pages and characters into editable text file.
Bar Code Scanner:
These scanners are used to convert bar code into digital information.
There are three types of scanners Hand – Held, Flatbed and Sheet-Fed.
Hand – Held scanner
A scanner that is held in hand and can scan the image while passing over the image. It is less expensive and small in size.
Flatbed scanner
A scanner that has a flat piece of glass. The documents are put on the glass upside down to scan it. It is more proficient than hand – held and sheet – fed scanner.
Sheet – fed scanner
A scanner that has nonmoving scan head, and feeds each sheet of paper across it. Obviously sheet – fed scanner cannot be used to scan pages in books or magazines etc.
Q - 9) Which device is used as input device as well as output device?
Ans: CD writer and Disk Drive are used as Input device as well as Output device.
As Input: When data is read by them.
As Output: When data is written on them.

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Q - 10) Define an input device & describe mouse or light pen: Input devices:
These are physicals equipment that read or translate data into electronic impulses which can be understood by computer. Such as Keyboard, Light Pen, Mouse, Trackball, Digital Camera etc. Mouse:
It is an input pointing device. This is used to move a pointer on the computer screen in order to point to a place on display screen, to select on or more action to be taken for the position. It requires horizontal flat surface to use it easily. It has two buttons and one scrolling ring between them. Light pen:
It is also input pointing device that contains a photo detector or light source, and that allow integration with a computer through specially designed monitor. Generally it is used for engineering designing. It can be used at tablet PC.
Q - 11) Define Joystick, Microphone and Digital camera: Joystick:
It is a hand held stick, which is used as a pointing device. Mostly it is used for computer or video games and occasionally used for CAD/CAM systems. Microphone:
It is an input device used to record voice and speech. It is useful to arrange audio conference through internet. Digital camera:
It is a hand held and portable input device that takes pictures as input. It captures images electronically without the need of a film. It can also store images in its memory.

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Q - 12) Define Dual purpose device. Also Describe Disk Drive and CD- writer? Dual Devices:
These devices handle the data and information as well as input and output at the same time. Such as: CD – Writer and Disk Drive.
CD - Writer:
It is a dual purpose device that can read or write information to CD–RW or CD–R discs. It is also called CD–R drive. CD–R drives can also read CD–ROMS and play audio songs. Data can be written, erased and rewritten on CD–RW while CD–R discs can be used only once for this purpose. Its speed measures in "X" unit.
Where 1X = 150 kb/s.
Disk drive:
It is a peripheral device that reads or writes the disk (Hard-disk Floppy disks etc.) that stores information. It is also called storage device. It contains a motor to rotate the disk at a constant rate and one or more read/write heads over the desired track. It has radial (seeking) motion that causes noise; it has a set of locations (cylinder) that is accessible with head. It works until the desire location is found.
Q - 13) Define motherboard: Mother board:
It is the rectangular card containing the circuitry that connects the processor to the other hardware. Such as Sound card, Video cards, ports etc.
Q - 14) Define USB: USB:
It is a port that is called Universal Serial Port. It has advanced plug and play technology. It is high speed device interface to which up to 127 peripheral device can be connected.

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Q - 1) Define memory or memory storage:
Memory Storage: Memory refers to the place where data is kept for further use. Usually the term Memory identifies primary data storage that comes in form of chips, and the word Storage is used for memory that exists on tapes or diskettes etc.
Q - 2) Define RAM and ROM?
Ram stands for Random Access Memory.
The term RAM also refers to read and write memory.
It is volatile and requires a steady flow of electricity to maintain its contents.
It is also termed as main memory.
It is the fastest but most expensive type of storage.
There are its two basic types Dynamic Ram DRAM and Static Ram SRAM.
Rom stands for Read Only Memory.
It is non-volatile and pre-programed memory and responsible to start up the computer and perform diagnostics.
It has special program called Firmware.
There are several types of ROM such as PROM, EPROM and EEPROM.
Q - 3) Define various types of ROM?
ROM stands for Read Only Memory. There are several types of ROM that includes PROM, EPROM and EEPROM.
PROM: (Programmable Read Only Memory)
EPROM: (Erasable Programmable Read Only Memory)
EEPROM: (Electrically Erasable Programmable Read Only Memory)
Chapter Four
STORAGE DEVICES

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Q - 4) What is the difference between Static RAM and Dynamic RAM?
DRAM:
It is the most common type of memory.
It needs to be refreshed thousands of times per second.
It is not more expensive and slower.
SRAM:
It is also common type of memory.
It does not need to be refreshed which makes it faster.
It is more expensive than Dynamic RAM.
Q - 5) What is the difference between SIMM and DIMM?
SIMM:
It has one or more RAM chips on a small circuit board with pins.
It typically comes with 32 data bits that requires 72 pins connectors.
It is always installed in in-line pairs since each supports 32 bit path.
DIMM:
It also has one or more RAM chips on a small circuit board with pins.
It typically comes with 64 data bits that requires 168 pins connectors.
It can be installed without a pair that supports 64 or more bit path.
Q - 6) Define Backing or Secondry memory/storage? And describe any two of them: Secondry (Backing) Memory/Storage:
Secondry or Backing storage is also called auxiliary storage or external memory that is used to store huge amount of data for longer period of time and that is not currently being processed. It is nonvolatile, slowest and cheapest form of memory. Secondary memory devices include magnetic storage devices like floppy disks, Hard Disks and Magnetic Tapes (the first forms of secondary memory); and optical disks such as CDs and CD -ROMs.

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Floppy Diskette:
It is small removable, portable storage device that is made of polyester film coated with metal oxide compound. The physical size of disks has shrunk from the early 8 inch to 3.2 inch and about 2mm thick while the data capacity has risen. It may be either single or double sided. It is divided into tracks and sectors. CD ROM:
It is an adaptation of the CD that is designed to store computer data. It is a nonvolatile optical data storage medium that is physically the same as an audio CD. It has spiral tracks that hold almost 650 MB to 2 GB of data and the track pitch can range from 1.5 to 1.7 microns. It can run audio and video CDs as well as game and different software's CDs. Its speed is measured in "X" units such as 12x, 32x and 64x etc. Hard Disk:
It is a magnetic disk on which we can store more data faster than floppies. It is less portable but has huge capacity for storage data. It is rigid aluminum and a set of stacked disk. The surface is divided into concentric circular tracks. It has cylinder, two heads, sectors and seeker. It speeds varying from 4500 to 7200 rpm. Disk access time is measured in milliseconds. Magnetic Tape:
It is also a storage device form which we can access data serially like and audio cassette. Serial access is slower than the direct access so the best use of it is for that data we do not use frequently. It is plastic tape coated with some magnetic material and its width 1.27cm, length 731.5m and diameter is 25.4cm. It has two gaps Inter block which separates logical block and Inter record which separate records.

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Q - 1) Define Data and briefly state its kind:
Data:
Mainly data is divided into two types: (A) Numeric data (B) Character data
(a) Numeric data: Data in form of numbers is known as Numeric Data. It includes 0 to 9 digits, decimal point (.), (+,-) sign and the letters "A" or "S" etc.
It is also divided into two groups: (i) Integer Data (ii) Real Data
(i) Integer Data: It is in form of whole numbers that does not contain decimal point. However it could be positive or negative.
Such as +366, -56, 70
(ii) Real Data: It is in form of fractional numbers. It contains a decimal point. It can be positive or negative. It is further divided into two types:
 Fixed point: It is in form of (0 − 9) digits, decimals points (.) and (+ 표푟 −) sign. Such as +0.36, -5.322 or 7.002 etc.
 Floating point: It is in form of (0 - 9) digits, decimals points (.) and (+ 표푟 −) sign as well as exponential form. Such as 1.602×10−19
(b) Character data:
(i) String Data: It consists of sequence of characters. It is further divided into two types.
 Alphabetic Data: It is the composition of English alphabets. Such as Ahtisham, Pen, school, computer file etc.
 Alphanumeric Data: It consists letters with numbers and symbols: Such as 100/WSC, DHA – 10, Block 9 etc.
(ii) Graphical Data: It is in form of charts, images, maps and drawing etc. Scanners normally use to inter this type of data.
Chapter Five
DATA REPRESENTATION

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Q - 2) What is number system? How many types of number system are there?
Number system:
It is the system of counting and calculation. The number of digits a system uses is called its base or radix. There are four types of number systems used in computer operations.
(i) Decimal System:
This system is same as general mathematics and we use this system in our daily life for calculations. Its base is ten “10” because it contains 0 to 9 digits in repeat order.
(ii) Binary system:
This system is ideal for internal working of electronic computers. Base of this system is 2. Thus, this system contains only two primary digits “0” for ON and “1” for OFF.
(iii) Octal system:
This system is used in programing as shortcut to binary system. Base of this system is 8. So, this system contains only 0 to 7 digits.
(iv) Hexadecimal System:
This system is also used in programing as shortcut to binary system. Base of this system is 16. So, this system contains 0 to 9 digits and first six letters of English alphabets A to F. A for 10, B for 11 and so on.
Q - 3) Define Codes and how many types are used in computer system?
Codes: When number, letters or words are represented by special group of symbols, they are being encoded and the group of symbols is called “Codes”. There are three types of codes used in computer system. Such as (1) Binary Code (2) Binary Coded Decimal (BCD) (3) Alphanumeric Codes
a) Binary Codes: When a decimal number is represented by its equivalent binary number it is called "Binary Coding" or "Binary codes." Such as (111010)2
b) Binary Coded Decimal Code (BCD): It is a method of using binary digits to represent the decimal digits. The binary coded decimal is an 8421 CODE.
c) Alphanumeric Codes:
It represents all of the various characters that are found on computer Keyboard. In this way computer can recognize 256 different characters. There are two most popular coding schemes (i) ASCII (ii) EBCDIC
Decimal
0
1
2
3
4
5
6
7
8
9
BCD/8421
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001

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Q - 4) Which number system computer uses for processing of data & why?
Ans: Computer uses Binary Number system for processing data because computer can only understand two basic digits 0 for ON and 1 for OFF. That's why all instructions are given to computer converted into binary numbers for processing.
Q - 5) How many types of coding schemes are used in computer system? Or define the various coding schemes used in the computer system?
Coding Scheme: There are two most popular coding schemes used in computer system in this Era.
a) ASCII
Stands for American Standard Code for Information Interchange. It has 265 characters and symbols represent by an 8-bit code series. The first 32 codes in the ASCII table represent control characters that are not printed or displayed. The other characters are graphic symbols that can be printed or displayed.
b) EBCDIC
Stands for Extended Coded Decimals Interchange Code. It is another 8-bit code popularly used in Mainframe computers and Mini computers. These codes are not used in personal computers.
Q - 3) What is complement of a number? How 1st and 2nd complements are represented in computers? Complement: The term complement refers to the sign of number either it is negative ( − ) or positive ( + ). These also handle negative numbers. 0 is for positive and 1 is for negative.
1st complement: It is formed by changing all 1s to 0s and all 0s to 1s.
Binary Number
1
1
0
0
1
0
1
1st complement
0
0
1
1
0
1
0
2nd complement: It is formed by adding 1 to the least significant bit (LSB) of 1st complement. Or start from right with LSB and write the bits as they are up to and including the first 1 and then take 1st complement of remaining bits.
General method
Alternative method
2nd complement = ( 1st complement ) + 1
1st complement (bit stay same with starting 1)
Binary number
1
0
0
1
0
Binary number
1
0
0
1
0
1st complement
0
1
1
0
1
2nd complement
0
1
1
1
0
Add 1
+
1
1st complement
2nd complement
0
1
1
1
0
Bits stay same

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Q - 1) What is Boolean algebra? Or Define Boolean algebra. Boolean algebra: It is a convenient and systematic way of expressing and analyzing the operations of logical circuits. It is a mathematical system for formulating logical statements with symbols. It provides Operations and Rules for working with the set {0, 1}.
Q - 2) What are the laws of Boolean algebra? State their various types:
Ans: There are three well-defined laws of Boolean algebra as follows:
(a) Commutative Law (b) Associative Law (c) Distributive Law Commutative law:
It states that the order in which the variables are ORed or ANDed makes no difference.
For Addition: A + B = B + A and For Multiplication A.B = B.A Associative law:
It states that when ORing or ANDing more than two variables, the result is the same regardless the grouping of the variables.
For Addition: A + (B + C) = (A + B) + C and For Multiplication A (BC) = (AB) C Distributive law:
It states that ORing two or more variable and ANDing the result with a single variable is equivalent to ANDing the single variable with each of the two or more variables and then ORing the products.
For Addition: A (B + C) = AB + AC and For Multiplication AB + AC = A (B + C)
Q - 3) What are the Logical Operators of Boolean Algebra:
Ans: There are three logical operators of Boolean algebra as follows:
(a) OR (b) AND (c) NOT
OR operator:
This operation is represented by a "+" sign and it is used for logical additions or Boolean sum.
AND operator:
This operation is represented by a "." sign and it is used for logical multiplications or Boolean products.
NOT operator:
This operation is represented by a prime (‘) or (−) sign on the variable and it is used for complement operations.
Chapter Six
BOOLEAN ALGEBRA

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Q - 4) Define Boolean Expression and Boolean Function:
Boolean Expression:
A Boolean Expression is an arrangement of variables and logical operators used to express the operation of a logic circuit.
Such as A (B + C) = AB + AC
Boolean Function:
A Boolean Function is an expression formed with variables, binary operators’ parentheses and equal sign.
Such as W = X + Y.Z
Q - 5) What are the rules of Boolean Algebra:
Ans: Rules of Boolean algebra are useful in manipulating and simplifying expression. There are twelve rules of Boolean algebra: A + 0 = A
A variable ORed with 0 is always equal to the variable. A + 1 = 1
A variable ORed with 1 is always equal to the 1. A. 0 = 0
A variable ANDed with 0 is always equal to the 0. A. 1 = A
A variable ANDed with 1 is always equal to the variable. A + A = A
A variable ORed with itself is always equal to the variable. A. A = A
A variable ANDed with itself is always equal to the variable. A + A̅ = 1
A variable ORed with its complement is always equal to 1. A. A̅ = 0
A variable ANDed with its complement is always equal to 0. A̿ = A
The double complement of a variable is always equal to the variable. A + A.B = A
This rule can be proved by applying the distributive law, rule 2 and rule 4. A + A̅ .B = A + B
This rule can be proved by applying rule 10, rule 6, rule 8, rule 7 and rule 4. (A + B) (A + C) = A + BC
This rule can be proved by applying the distributive law rule 6, rule 2, and rule 4.

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Q - 6) Define the following terms:
Constant: It is an item of data which remain unchanged for each run. Boolean algebra uses binary values 0 and 1 as Boolean constant.
Variable: The variables used in Boolean Algebra are represented by letters such as A, B, x, y etc. with each variable having one of two (0,1) distinct values.
Complement: It is the inverse of a variable and is indicated by a bar (̅) or prime (‘) over the variable.
Truth Table: It represents the conditions of Input and Output circuit involving two or more variables.
Q - 7) State and prove the De-Morgan's theorems:
Ans: De-Morgan, A mathematician proposed two important theorems of the Boolean algebra to help in simplifying complicated logical expression.
(1) x.y̅̅̅̅=x̅+y̅ This states that the complement of a product of variable is equal to the sum of complements of the variables:
Proof:
Truth Table
푥
푦
푥.푦
푥.푦̅̅̅̅̅
푥̅
푦̅
푥̅ + 푦̅
0
0
0
1
1
1
1
0
1
0
1
1
0
1
1
0
0
1
0
1
1
1
1
1
0
0
0
0
(2) x+y̅̅̅̅̅̅̅=x.y̅̅̅̅ This states that the complement of a sum of variable is equal to the complements of product of the variables:
Proof:
Truth Table
푥
푦
푥+푦
푥+푦̅̅̅̅̅̅̅
푥̅
푦̅
푥.푦̅̅̅̅̅
0
0
0
1
1
1
1
0
1
1
0
1
0
0
1
0
1
0
0
1
0
1
1
1
0
0
0
0
Equal Equal

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Q - 8) What are the standard forms of Boolean expression:
Ans: There are two standard forms of all Boolean Expression:
(a) Sum of product (SOP) (b) Product of Sum (POS)
(a) Sum of product (SOP): When two or more terms are summed by addition, the resulting expression is a Sum of product (SOP).
For Example: ABC + CDE + CDB
(b) Product of Sum (POS): When two or more terms are multiplied, the resulting expression is a Product of Sum (POS).
For Example: (A +B) (B + C) and A (B+C)
Q - 9) What is Karnaugh map? How can Karnaugh map help in simplifying a Boolean expression?
Karnaugh Map:
It provides a systematic method for simplifying Boolean Expressions. It is also known as K-map. It is similar to a Truth Table and help in simplifying Boolean expression because it presents all of possible values of Input variables and the resulting Output for each value. It is an array of cells, and it can be used for expressions with two, three or more variable.
0
1
0
A ̅B̅
A̅ B
1
AB̅
AB
0
1
00
A̅ B̅ C̅
A̅ B̅ C
01
A̅ BC̅
A̅ BC
11
ABC̅
ABC
10
AB̅ C̅
AB̅ C
00
01
11
10
00
A̅B̅ C̅ D̅
A̅ B̅ C̅ D
A̅ B̅ CD
A̅ B̅ CD̅
01
A̅ BC̅ D̅
A̅ BC̅ D
A̅ BCD
A̅ BCD̅
11
ABC̅ D̅
ABC̅ D
ABCD
ABCD̅
10
AB̅ C̅ D̅
AB̅ C̅ D
AB̅ CD
AB̅ CD̅

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Q - 1) What is software? Describes various types of software: Software:
The term software applied to all those programs which some way can assist all users of a particular type of computer to make the best use of their machine. There are two types of software:
(a) System Software (b) Application Software (a) System software:
This software performs tasks associated with controlling and utilizing computer hardware. Types of System software is as follows:
(i)
It is a set of programs that controls and supervises programmers and users of computer.
(ii)
It translates a computer programs into machine understandable form. Interpreter, Compiler and Assembler are language translators.
(iii)
This software is used for organizing, updating and printing data.
(iv)
This software enables the user to type-in a program or generate test and make modification whenever necessary.
(v)
This software are used to perform a wide range of functions like virus cleaning, fixing registry errors etc.
(b) Application Software:
This software helps user to perform a specific job or task. These are two types (i) General purpose (ii) Special purpose
(i)
These are called packaged software or commercial software. By using this software user fulfill his general needs. Such as: Ms. Office, Adobe Photoshop, Anti- virus etc.
(ii)
This software is designed to perform only one specific task for which it has been designed. These are also called custom software. Such as: Inventory Control, Airline Booking System Software etc.
Chapter Seven
COMPUTER SOFTWARE

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Q - 2) What is an operating system?
Operating System:
It is a set of programs that controls and supervises the hardware of a computer and provides services to applications software, programmers and users of computer. DOS, Windows, UNIX, Linux, Solaris. Etc. are some popular operating system.
Q - 3) What are language translators? Define each:
Language Translators translate computer program into machine explicable form. Interpreter, Compiler and Assembler are language translators:
Interpreter: It translates and executes each program statement one at time, translation is required if program is run again.
Compiler: It translates the whole program at a time and stores translated program on disk. Original program is called "Source program" while translated program is called "Object program".
Assembler: It translates Low Level programs or assembly language into machine language. It is also used to convert symbolic language.
Q - 4) What are characteristics of disk operating system (DOS)?
Disk Operating System (DOS):
It manages the routine work of computer system, controlling everything from internal memory, monitor display, keyboard input and external communication.
Characteristic of DOS
It has character C :> as prompt. It can be changed by typing drive letters as D, E, and F etc.
It stores data as filing and name of any file must be written in two parts (i) File Name and (ii) Extension. Such as ahti.txt or APS.exe
Wild cards (*,) can be used while looking for particular file.
It is command line operating system that includes Internal and External commands.

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Q - 5) What are the types of DOS commands:
Ans: There are two types of DOS commands internal and external.
Internal Command:
These are built into DOS and loaded with it when computer is getting started. These command immediately available in memory and cannot be seen on disk.
Such as VOL, REN, CLS, TIME, MD, CD, COPY etc.
External Command:
These commands are stored as files. DOS must reads these commands form the disk before execution.
Such as Format, Label, Disk copy, Edit, Delete, Sys, Xcopy, Doskey etc.
Q - 6) What are Wildcard characters? Why are they used?
Ans: There are the special characters such as (?) and (*).
Uses of Wildcard:
These are used for searching or deleting specific files on disk without entering each file name separately. Such as *.txt, *.bin or ahti?
Q - 7) What is Directory? And what DOS commands are used to create, change or delete directory:
Directory:
A directory contains information about each file such as its name, size in bytes, the date and time they were created or last updated. The main directory is called Root Directory.
For Example:

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Q - 8) What is the difference between DOS and Windows operating system? or Distinguish between DOS and Windows operating system:
Difference between DOS and Windows Operating System
DOS Operating System:
 It is text based colorless operating system that deals with 16 bits processing.
 It is command line system only one command can be used at a time.
 Its interface is dark only text can be seen or write on it.
 It does not require any driver for supporting devices such as mouse, CD-ROM etc.
 It manages the routine work of computer system.
Windows Operating System:
 It is colorful and graphical user interface that has colorful images on desktop.
 In windows the commands are located on the screen in form of pictures called icon. Mouse controls these commands.
 It helps in 32-bits or 64-bits data processing with multi commands tasking.
 It requires drivers for different devices such as CD-ROM Sound card, modem etc.
 It gives friendly environment to all users any one can use it according to his need.

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Q - 1) Define or what is Desktop? What are its elements?
Desktop:
It is working surface, when computer is started using Windows, it displays a screen, called “Desktop.” Usually a desktop screen contains icons, task bar, start button etc. Nowadays we can add different gadgets on desktop. Components/Elements of Desktop: or (Short Note)
It contains Icons, Taskbar, Start buttons etc. Icons:
It is small colorful graphical picture that represents an objects. Such as file, folder and program etc. We may change name and position of an icon. We can also delete and change it as well. are icons. Taskbar:
It is at the bottom of desktop but can be moved in any side of the screen. Currently running programs appear on it. It has two side. At left side there is a start button and on right side it has system tray that show various operations as system clock.
Start Button:
It is at the lower left corner of the screen. Through this button we can open program installed on computer and access all the utilities available in the windows environment. We can shutdown, restart, stand by or etc. by using this button. It displays a menu of choices: As Programs, Find or search box, Run, etc.
Chapter Eight
INTRODUCTION TO WINDOWS OPERATING SYSTEM
Task Bar Search Box
Start Button with Menu List

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Q - 2) Explain the functions of windows Explorer?
Windows Explorer:
It provides the way to view the contents of the disks and its folders in a tree like structure. We can navigate between files and folders by it.
Functions of Windows Explorer:



Q - 3) How can you search a file and folder? Find/Search: We can find file or folder by performing following steps:
(i) First of all click on Find option of the start button or press F3 (Function Key) then, Find Dialog box will appear.
(ii) Enter name of file or folder in the name text box.
(iii) And then click on find now option or press Enter button.
Q - 4) How can you install a printer? Installing Printer:
We can install a printer by performing following steps:
(i) Open Control panel then click on printer’s option the dialog box will appear.
(ii) Click on Add new printer then choose name of company and model of the printer.
(iii) And then click on Install option (OK button) or press Enter key for installing it.
Q - 5) How can you change wallpaper of the Desktop?
Changing Wallpaper of Desktop:
We can do this by performing following steps:
(i)
(ii)
(iii)
(iv)

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Q - 6) What is the procedure of setting a Screen Saver?
Setting Screen Saver:
We can set it by performing following steps:
(i)
(ii)
(iii)
(iv)
Q - 7) What is the function of Start Button?
Function of Start Button:
The function of start button are as follows:
(i)
(ii)
Q - 8) What is a computer virus? How a virus is removed from disk?
Virus:
Anti-virus:
Q - 9) What do mean by file and folder?
File:
Folder:

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Q - 10) What is the function of Control Panel? And define each item of Control Panel: or Write a short note on Control Panel:
Control Panel:
It facilitates to change the way windows works and looks. It contains list of icons through which we may change the settings of the computer.
Function of Control Panel:
It provides several of icons to set or change the way of windows operating system.
Most frequently used are as follows:
Accessibility Options: It makes computer easier for people with disabilities to operate a computer without installing special software.
Add new Hardware: It is used to install a new hardware to the computer. For example we can connect digital camera and install its driver with this icon.
Add/Remove Program: It is used to install new software or remove unnecessary software form the hard disk.
Date/Time: It is used to change or set the date or time of the computer system.
Display: It is used to change or set display setting of the Monitor Screen or Desktop. Such as wallpaper, screen savers and color of windows task bar with dialog box etc.
Fonts: It is used to install new fonts in the system font’s folder. We can also copy and remove fonts from this.
Internet Options: It is used to change setting for web browsers software.
Modems: It is a hardware device that is used to make a dial up networking for computer users for browsing internet.
Mouse: It is used to change pointer styles and button setting of the mouse.
Printer: It is used to install new printer to the computer system and setting of it.
System: It provides us system information about all devices connected to the computer.

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Q - 11) Write a short note on Recycle Bin:
Recycle Bin:
Every window has recycle bin by default. It makes it easy to delete and undelete files and folders. When a file is removed from disk or folder windows stores it in Recycle Bin. It is helpful when a file is deleted accidentally we can move it back from Recycle Bin. We can also empty it to save disk space for more storage.
Q - 12) What is the installation procedure of windows?
Procedure of installing windows:
First of all insert bootable windows CD into CD-ROM.
1) And then restart computer, after restarting, the sentence will appear on monitor screen “Press any key to continue” then press Enter key.
2) Now setup procedure will start, it will ask target drive for installing windows such as C, D or E.
3) Format the target drive if necessary.
4) Choose any desire drive but make sure the drive has enough space to install windows.
5) Read the information presented in the dialog box, then click continue. Windows will perform quick survey of the system. Click next to continue installation.
6) The installations total time vary from 30 to 60 minutes or depending on the system speed.
7) After installation, windows will perform some system task click next to continue. Now a window is installed and ready to use.
Q - 13) Differentiate between the following: Documents My Document
It lists the files we have recently worked on. Such as files or papers, graphics, documents etc.
It is a desktop folder that provides suitable place to store documents, graphic, etc.
We can open most recently used documents directly form here.
It is represented by a folder with a sheet of papers in it, on desktop.

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Windows Explorer My Computer
It is a way to view the contents of the disks and its folders in a tree like structure.
It is also use to view the contents of the disks and its folder in single screen window.
It has two panes. Left and right panes.
It does not have any panes by default.
Left pane displays disk drives and folders while right pane displays the contents of selected item.
It is used to access information stored in different storage devices Such as Hard disk, CD – ROM or Floppy disk etc.
We can execute or run program from here.
We can also execute or run program from here. Task Bar Menu Bar
It is located at the bottom of the desktop by default. But we can move it.
It is always top of the opened window and cannot be moved any side.
It contains Start button, Address Bar, System tray etc.
It contains different menu list such as File, Edit, View etc.
It always shows the clock and currently running programs.
Every program has its own menu bar with different lists of menu. Wallpaper Screen Saver
It is an image or color set of the background of desktop.
It is an animated image or text that displays on screen when it runs.
We can change it easily. It is also called desktop background.
It appears when we stop working or leave system idle for some time.
It raises appearance of desktop.
It increases the life of the monitor. Data Information
It is collection of facts and figures.
It is processed form of data.
It is a set of numbers, letters or words.
It is complete form of letters or word such as sentence.

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Glossary
Algorithm
It is a series of instructions or procedural steps for the solution of a specific problem.
Algorithm Code
It is a system of coding data by the use of combination of letters to represent item of information. Alphanumeric Code
Pertaining to character set or field of data in which the coded characters may represent numerals or letters of the alphabets.
Analog Computers
Analog computers are machines designed to perform arithmetical functions upon numbers where the numbers are represented by some physical quantity.
Antivirus Utility
A program that scans disks and memory for virus detects and remove them.
Application Program
It is a program forming part of a user's job and written by the user. As distinct from program forming part of the general purpose software used to manage the operation of the total computer system.
ASCII Code
It is acronym for American Standard Code for Information Interchange.
Assembler Computer program that converts the assembly language program into machine on a language.
Assembly Language
Any symbolic language used for programming which must go through an assembler in order to be converted into the machine code required for operation on a computer.
BASIC
It is an acronym for Beginner's All-purpose Symbolic Instruction Code. It is a high level programming language. Because of its simplicity and comparative power, the language is much used on personal computers.

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BIT
It is an acronym for Binary digit, one of the two digits (0 and 1) used in binary notation. BUG
It is any mistake or malfunction of a computer program or system.
BYTE
It is a set of bits considered as a unit, normally consists of 8 bits and corresponds to a single character of information.
Character One of a set of symbols in a data processing system used to denote, for example numerals 0 – 9, the letters of the alphabet, punctuation marks, etc.
COBOL COBOL is an acronym for Common Business Oriented Language. It is an internationally accepted programming language developed for general commercial use.
Code it is the representation of data or instruction in symbolic form.
Coding
It is the written instruction for a computer coding is the part of activity of programming.
Compilation
It is the process of using a compiler to create an object program from a source language.
Compile To create an object program by means of a compiler.
Compiler A complex program which converts computer instructions written in a source language into machine code.
Computer Any machines which can accept data in a prescribed form process the data and supply the results of the processing in a specific format as information or as signals to control automatically some further machine or process.

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Computer Program
It is a program written in a computer language. Computer Simulation, Representing a system or a process by a computer model constructed from a computer program.
Computer Word
A fixed sequence of bits, bytes, or characters treated as a unit and capable of being stored in one storage location.
Constants In program constants are items of data which remain unchanged for each run.
Cursor
It is a special character, usually a flashing square block or underline, which indicates the position on a screen at which the next information character will displayed.
Data
It general expression used to describe any group of operands or factors consisting of numbers, alphabetic characters or symbols which denote any conditions, value or state.
Data processing
The operations performed on data, usually by automatic electronic equipment, in order to derive information or to achieve order among files.
Debugging Debugging is the technique of detecting, diagnosing and correcting errors or bugs which may occur in programs or system.
Decision Symbol
A flow charting symbol used to indicate a choice or branching in the information processing path. A diamond shape figure is used to represent this symbol.
Difference
It is the result obtained in the arithmetic operation of subtraction.
Digit
It is a component of an item of data.

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Digital Computer
A digital computer is a machine capable of performing operations on data represented in digital or number form, Disk: A revolving plate upon which data and programs are stored. DOS
It is an acronym for Disk Operating System.
Document
It is any form or voucher containing detail of some factors.
Documentation
It is the process of collecting, organizing and storing all the information related to a specific program like flowchart, algorithm, coding sheets, manuals etc. on papers.
EBCDIC
It is a data communication code in which 8 information bits are used to form 256 unique character codes. The term is an abbreviation of Extended Binary Coded Decimal Interchange Code.
EOF BASIC
It is reserved word which is an abbreviation of End Of File.
Equivalence
It is a logical relationship in which two statement are said to be equivalent.
Error
It is any condition in which the unexpected results of a compiled object code are obtained. Expression
It is the symbolic representation of a mathematical or logical statement.
Field
It is a sub division of a record containing a unit of information.
File
It is an organized collection of records.
Floating Point Number
A form of number representation in which quantities are represented by a number called the mantissa multiplied by a power of the number base called exponent.
Flow Chart
It is the diagrammatic representation of a sequence of events, usually drawn with conventional symbol representing different types of events and their interconnection.
Format
It is the predetermined arrangement of data.
Function
That part of a computer instruction which specifies the operation to be performed.

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Giga
It is a prefix denoting one thousand million.
Graphics
It is the use of images generated by software for output to a graphic display.
Hard Disk
It is a magnetic disk which is rigid.
High Level Language
It is a computer language which is nearest to human language. A language in which each instruction or statement corresponds to several machine code instructions.
Hybrid Computer
Any mixed computer system in which analog and digital computing devices are combined.
Hz
It is abbreviation of Hertz.
Information
It is the result which is derived from the processing of data.
Input
It is the process of transferring data, or program instructions, into memory from some peripheral unit.
Instruction
It is that part of a computer program which tells the computer what function to perform at that stage.
Interpreter
It is software that translates each statement of source program into a sequence of machine instructions and executes these machine instructions one by one before translating the next source language statement.
Jump
Synonymous with branch.
Keyboard
It is an input device to feed alphabetic and numeric data.
Kilobyte
It is 1024 bytes.
Label
It is a DOS command which is used to assign a label to the disk.
Load
This is BASIC command which is used to load a BASIC program from a secondary storage device to computer's memory.

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Locate
This is BASIC command which is used to show the location of cursor on the screen.
Loop
It is series of instructions which are performed repeatedly until some specified condition is satisfied.
Machine Language
The coding system adopted in the design of a computer to represent the instruction of the computer.
Magnetic Disk
A storage device consisting of a number of flat circular plates each coated on both surface with some magnet able material.
Main Storage
It is the store from which instructions are executed.
Megabyte
It is a million bytes.
Memory This term is usually reserved for describing the internal store of a computer.
Microcomputer
It is a computer based on microprocessor.
Modem
It is a device which transmits over distances without error.
Nested Loop
Programs fling technique in which a loop of instructions contains another loop, which may in turn contain another, and so on.
Numeral
It is one of a set of digits that may be used in a particular system of number system.
Numerical Data
It is any field of characters which contains numeric digits only.
Object Program
It is a program in which language produced by translating the program written in source language through the use of a compiler.
Operating System
A set of programs which manages resources of computer include hardware, programs, data and operators.
Output
Result produced by a computer.

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Output Device
It is the device which produces the results from the computer in human readable form. Printer An output device which produce results in printed form.
Procedure The sequence of steps required in order to solve a problem.
Program
It is a set of instructions composed for solving a given problem by computer.
Programming Language
A language used for writing computer programs.
Prompt
It is any message given to an operator by an operating system.
RUN
It is the performance of one program or routine.
RAM
It is Abbreviation of Random Access Memory. Memory into which data can be written and from which data can be read.
Reserved Word
In a programming language, a data name not available to the user because it has some specific significance to the computer.
Resolution
It is the number of individually addressable and variable picture elements available in a graphic display.
ROM
It is acronym for Read only Memory. Memory containing information which is permanent and which cannot be written to, but can be read by program functions.
Soft Copy
It is output from a computer process which is displayed on a visual display unit.
Software The term is applied to all those programs which in some way can assist all users of a particular type of computer to make the best use of their machine.
Source Program
It is a program written in a source language.
Statement A source language instruction.

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Structured Programming
A methodology for programming which involves systematic described in increasing detail until the final stage of coding is required.
Subroutine
It is part of a program which performs a logical section of the overall function of the program and which is available whenever the particular set of instructions is required.
Subscripted Variable
Whose numeric value can change? It is denoted by an array name followed by a subscript; e.g. A (5) or AB$(22)
Standalone
A standalone device is able to function independently of other hardware. This means it is not integrated into another.
Standby
When electronic devices are receiving power but are not running, they are in standby mode. For example, a television
Streaming
Data streaming, commonly seen in the forms of audio and video streaming, is when a multimedia file can be played back.
Tablet
A tablet is a flat, portable computer with a touchscreen interface. Early tablets required a stylus or light pen, but...
Tag
On clothes, tags usually indicate the brand, size of the garment, fabrics used, and the washing instructions. In Web.
Tape Drive
This is a removable storage device mainly used for backing up data. It is similar to a Zip Drive, but instead of Zip.
Target Disk Mode
Target disk mode is a way of booting a Macintosh computer so that it acts as an external hard drive on another.
Task Bar
The task bar was introduced with Windows 95 and has been part of every version of Windows since then. It is the bar.
TCP/IP
Stands for "Transmission Control Protocol/Internet Protocol." These two protocols were developed in the early days.

Computer for Class IX Guide

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