Computer Science 2010

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1. Explain different types of input/output devices??

Ans:Input devices are used to enter data and instructions into computer memory

from external world. Examples include: Keyboard, Mouse, Track ball, Track Pad, Joy

stick, Touch Screen, Light pen, Touch Screen, Scanner, Digital Camera, Microphone,

Graphics tablet. They perform three main functions

1. Receive data from user

2. Convert data into binary form [the language of 0 and 1 also called the machine

language. Machine language is the only language, a computer can understand

directly.]

3. Provide converted data to computer memory for processing

Key board:Keyboard is the most familiar input device. It is most widely used input device to enter data and

instructions into the computer. Keyboard has a set of keys like a typewriter. It has alphabetic keys for

A,B,CZ or a,b,c,z. It has numeric keys like 0,1,2,3,9. It has function keys F1,F2,F12 used to

perform specific tasks.

It has other keys used for editing like Delete, Backspace, Home, End, etc.

Mouse:Mouse is an input device used to control motion of pointer on screen. A mouse

has two or three buttons called Left, Right and Middle button. Buttons are used to

perform different functions. It has a rubber or metal ball inside its body. Mouse is

rolled over a flat surface called mouse pad. The movement of ball is detected by

internal circuits of mouse. These circuits convert this movement into digital signals,

which are sent to computer. Mouse is used in graphical applications. It is also used for

playing video games on computer.Track Ball: Track Ball is an input device like a mouse. It is used in Lap top computers to control motion of

pointer on screen. It is a pointing device like upside down mouse. It has a ball on its upper side. This ball is

moved by fingers or thumb and the pointer moves accordingly on screen.

Track Pad: Track pad is a pointing input device. It is used in Lap top computers to control motion of

pointer on screen. Track pad is a stationary input device. It has a flat surface of 1.5 to 2 square inch. Finger

is moved on this surface to move pointer on screen.

Joy stick:Joystick is an input device used to play games on computer. It is used to control motion of an

object quickly in game with the help of a hand held stick. This stick can be moved forward, backward or

side ways. This stick is mounted on a ball. When stick is moved then ball is moved and signals are sent tothe computer.

Light Pen:Light pen is an input device consisting of a special pen that is connected to a computer's

monitor. The user points at the screen with the pen and selects items or chooses commands either by

pressing a clip on the side of the light pen or by pressing the light pen against the surface of the screen (the

equivalent of performing a mouse click).

Microphone:Microphone is an input device used to enter sounds into the computer. We can record sounds

in computer with the help of microphone and sound card.

8. Scanner:Scanner is an input device. It is used to save pictures or text on paper into computer memory.It converts picture or text on paper in to binary form and saves it in computer memory. With the help of

scanner we may save our time to type a lot of text.


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9. Graphics tablet / digitizer:A graphics tablet consists of a special pen called stylus and a flat pad. The

image is created on the monitor screen as the user draws it on the pad with the help of stylus (special pen).

Graphics tablet is also called a digitizer.

10. Touch Screen:In ATM and in latest smart phones, touch screen is used to receive input from the user.

The user enters data by the touch of his finger on different menu options or icons present on touch screen.

Output devices

Out put devices are used to display results of processing to the user. They perform the following functions:

1. Receive results from memory

2. Convert data into human readable form

3. Display results to the user

Examples include: Monitor, printer, plotter, speaker, and multimedia projector.

1. Monitor

Monitor is the most commonly used output device used to display results of processing. It has a TV like

shape. Pictures on monitor are formed with picture elements called PIXEL. Monitors may be Monochrome

that will display results in Black & White. Color Monitors are also available. They display results in multi

colors. Monitor produces soft copy output.

2. Printers

Printers are used to produce hard copy out put. They print processing results on paper. Printers are divided

into two main categories:

Impact Printers

Non Impact printers

Impact Printers.

These printers print with striking of hammers or pins on ribbon. For example Dot Matrix printer and daisy

wheel printers are impact printers.

Non-Impact Printers.

These printers do not use striking mechanism for printing. They use electrostatic and laser technology.

Quality and speed of these printers is better than Impact printers. For example Laser printer and Inkjet

printers are non-impact printers.

3. Speaker

Speaker produces sound output. We can listen recorded voices, sounds or music with the help of speaker.Speaker produces sound output with the help of sound card.

4. Plotter


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Plotters are used to draw different designs of buildings or internal structure of machines. Mostly Engineers

and Architects use plotters.

5. Multimedia Projector.

Multimedia projector is used to produce computer output on a big screen. These are used in meeting rooms

or in classrooms of educational institutes.

2. Explain about secondary storage devices?

Ans:Storage devices are used to store data and instructions permanently. Storage devices are also called

secondary storage devices / backing storage devices / external storage devices or auxiliary storage devices.Examples of storage devices include Hard Disk, CD and DVD etc.

Why Secondary Storage Devices are Used?

Secondary storage devices are used because:

1. Primary memory(RAM) is volatile and temporary. When computer is switched off, all data in ram is

erased.

2. Storage devices can store large amounts of data and instructions permanently whereas Primary

memory has less capacity of storing data.

Types Of Storage Devices

There are three main types of storage devices:

1. Magnetic Tape 2. Magnetic Disk 3. Optical Disk

1. Magnetic Tape

Magnetic tape is the oldest storage device. It is made of plastic coated with magnetic material. Data is stored

on magnetic tape in the form of magnetic spots. Tape drive is used to read and write data on tape. Magneticdisk is sequential access device. It is slower device than magnetic disk or optical disk. Magnetic tapes are

used in reels of different lengths, for example 200, 600, 1200 feet etc.

2. Magnetic Disk

A magnetic disk is a thin circular metal or plastic disk coated with magnetic material. Data is stored in the

form of magnetic spots. Magnetic disk is random access device. It is faster than magnetic tape. There are

three main types of magnetic disk:

a. Hard Disk b. Floppy Disk c. Zip Disk

a. Hard Disk

The hard disk is also called fixed disk. It consists of one or more metal plates. The plates are fixed in the


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drive. Metal plates are coated with magnetic material to store data. A motor rotates disks. There is also an

access arm and read / write heads to read and write data on disks.

Following are major characteristics of hard disk:

- The storage capacity of hard disk is much greater than floppy disk.

- Now a days hard disks of size 40 GB, 80 GB or more are available.

- Hard disk is covered in a hard jacket and there are less chances of disk damage due to dust and

mishandling.

- Now days Operating system and application programs are installed on hard disk.

- Before using a magnetic disk we use operating system to format the disk. Operating system divides the

disk into circles called tracks. Each track is divided into pie-shaped areas called sectors. Data is stored in

sectors. Each sector can store 512 bytes.

b. Floppy Disk

Floppy disk is a small plastic plate coated with magnetic material. Data is stored in magnetic spots. Mainadvantage of floppy disk is that it is used to transfer data from one computer to another. Floppy disk drive is

used to read and write data on floppy disk.

Floppy disk is available in two sizes:

3 INCH Floppy Disk

It is also called micro floppy disk. Its diameter is 3 inch. It is covered in a hard plastic cover. Read/Write

window is covered with a metal shutter. When disk is inserted into disk drive then shutter is automatically

opened. It can be write protected by a notch. Storage capacity of micro floppy is 1.44 MB.

5 Inch floppy disk.

It is a 5 inch diameter plastic plate coated with magnetic material. Its storage capacity is 1.2 MB. It is not

used in modern computers.

c. Zip Disk

Zip disk is similar to 3 inch floppy disk. But it can store 100 MB or more data. Zip disk drive is used to

read and write data on a zip disk.

3. Optical Disk

LASER technology is used to read and write data on Optical disk. LASER stands for Light Amplification

through Emission of Radiation. Laser beam writes on the surface of optical disk by creating very small

holes. The presence of hole represents a One and absence of the hole represents a Zero. There are following

main types of optical disk.

1.CD-ROM, 2. CD-R or WORM, 3. CD-RW

4.DVD-ROM, 5. DVD-R, 6. DVD-RW

1. CD-ROM

CD-ROM stands for Compact Disk-Read Only Memory. The data stored on Cd-Rom can only be read. It

cannot be deleted or changed. It is a portable storage device. Data can be easily transferred by CD Rom from

one computer to another. Commonly it can store 650 MB / 700 MB/ 750 MB data. It is used to store large

amounts of data like Software or audio/video data.2. CD-R (CD Recordable) Or WORM (Write Once Read Many)

CD-R stands for Compact Disk -Recordable. Initially, it is a blank disk. User can store data on it only once.

This is why it is also called WORM(Write Once Read Many) disk too. Because we can write data on it only

once and later we can read many times. The devices to store data on CD-R are called CD Writers or CD


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Burners. We can write data on CD-R only once, but can read data many times. Because of this write once

read many quality, CD-R is often known as WORM(write once read many).

3. CD-RW ( CD Rewritable )

CD-RW stands for Compact Disk Rewritable. This is a special type of CD. User can write data on it, if there

is an error in writing data, he may erase the contents and rewrite again. CD-Writers are used to store data on

CD-RW.

4. DVD - Digital Video Disk (DVD-ROM)

DVD stands for Digital Video Disk. A laser beam with a short wave length is used to create very very small

holes on the surface of disk. So there are much more tiny holes on the surface of DVD as compared to that

of CD. Therefore, storage capacity of DVD is much larger than CD. It can store up to 17 GB or more data.

DVD-ROM is pre recorded and it can contain data like movies, videos and software etc. User cannot change

or delete data from DVD-ROM. It is read only.

5. DVD-R (DVD-Recordable)

DVD-R stands for Digital Video Disk Recordable. Initially it is a blank disk. User can store data on disk

only once. Then it becomes read only. It is normally used to store high definition video movies. DVD-

Writers are used to store data on DVD-R.

6. DVD-RW ( DVD Rewritable)

DVD-RW stands for Digital Video Disk Rewritable. User can write data on disk many times by erasing the

old data.

3. Explain about Primary memory?(or) Explain about Ram and ROM?

Ans:The primary memory or the main memory is part of the main computer system. Theprocessor or the CPU directly stores and retrieves information from it. This memory isaccessed by CPU, in random fashion. That means any location of this memory can beaccessed by the CPU to either read information from it, or to store information in it.The primary memory itself is implemented by two types of memory technologies. The

first is called Random Access Memory (RAM) and the other is read only memory(ROM).RAM

Ram stands for random Access Memory. Data in RAM can be accessed directly. Thatis, we can access data directly from any location of RAM in the same time. ThisRandom Access quality makes RAM a very fast memory. RAM is volatile. Data andprograms in RAM are erased when computer is turned off. Therefore RAM is atemporary memory. It is used to store those data and programs, which are currentlybeing executed by CPU. Ram is also called Primary Memory or Main Memory.Types of Ram:There are two main types of Ram.

Dynamic Ram (DRAM)

Dynamic Ram is widely used in personal computers. It is a cheaper kind of RAM. DRAM loses electric

charge with the passage of time, so DRAM needs to be refreshed frequently. Otherwise, it may lose data.


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Dram is recharged many times in a second. Therefore, it is slower than SRAM. Since CPU cannot access the

data from DRAM while it is in the process of refreshing or recharging.

Static Ram (SRAM)

Static Ram does not need to be refreshed again and again. So processor can access data from static RAM

faster than DRAM. There is no time wastage in refreshing the memory again and again. Static RAM is more

expensive and faster than DRAM. Static Ram is used to build a very fast memory called CACHE

(pronounces 'cash' ) memory.

ROM

ROM stands for Read Only Memory, because its contents can be read and used onlyand we cannot change or delete its contents. It is a non volatile memory. Its retains itscontents even after switching off the computer. Therefore, ROM does not requireelectricity to retain its contents. ROM is a permanent memory. The instructions in

ROM are written at the time of manufacturing by the manufacturer.

Importance of ROM

1. One important reason a computer needs ROM is that instructions stored in ROM(called ROM BIOS - Basic Input/output System)execute on start-up of computer andguide the computer what to do. They make the computer ready for work.2. ROM contains a set of start-up instructions to check that memory is functioning welland check for other hardware devices.Types of ROM

Following are the types of ROM

PROM

PROM stands for Programmable Read Only Memory. Instructions can be stored in PROM only once. Then

it becomes ROM and we cannot change instructions in it. Initially PROM is a blank chip. Once instructions

are written on it, then it become ROM. Now we cannot change or delete the instructions. If there is any error

in writing instructions then PROM chip becomes unusable.

EPROM

EPROM stands for Erasable Programmable Read Only Memory. Program instructions written on EPROM

can be erased and changed with the help of ultra violet rays. So if once we write instruction on this chip with

errors, we can erase wrong instructions and rewrite new instructions.

EEPROM

EPROM stands for Electrically Erasable Programmable Read Only Memory. Program instructions written

on EEPROM can be erased with the help of electricity and rewritten.

4. Explain the characteristics of a computer?

Ans:1. SpeedComputers work at a very high speed. They are much faster than humans.

A computer can perform billions of calculations in a second. Computer speed is measured in Mega Hertz

(MHz).

2. Storage


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A computer can store large amounts of data permanently.

3. Processing

A computer can process the given instructions. It can perform different types of processing like addition,

subtraction, multiplication and division.

4. Accuracy

Accuracy means the capability to provide results without any errors. Computer can process large amounts of

data and produce 100% accurate results.

5. Recalling

A computer can recall the stored data and information at any time, as and when required.

6. Cost Reduction

Computer can reduce cost. We can do a work in less time and cost by computer. A single person, with

computer, can do work of many people in an office.

8. Versatile

A computer can perform different types of tasks. We can use a computer in hospital, bank or at home.

9. No Feelings

Computer has no feelings. It cannot be affected by sorrows and happiness.

10. No IntelligenceComputer itself is not intelligent. It only follows the given instructions. If a computer is given a program for

addition it cannot perform subtraction by itself.

5. Explain Classification of Computers OR Explain Types of computer on the basisof Size, Shape and Resources, performance?

Ans:Computers are classified on the basis of size, speed and price as under:

Microcomputer or Personal Computer

Mini Computer

Mainframe Computer

Super Computer1. Micro Computers

Desktop Model computer

Micro computer is also called personal computer. It was introduced in 1970. It contains input devices,

output device, storage device, memory and processor. It is used by one person at a time. Examples of

personal computers are PC and Apple Macintosh. The major types of personal computers are desktop

computer and portable computer.

Desktop Computers

These computers can easily fit on a table or desktop, hence the name. These computers come in two models

or casings. In Desktop model, the system unit is placed on the desktop or table. Monitor is placed on the

system unit. In Tower model, both monitor and system unit are placed on the table.

Portable Computer

Portable is a personal computer that can be carried from one place to other easily.Notebook computer and handheld computer (smart phone) are examples of portable computers.Notebook computer is also called laptop computer. Laptop computers are very small in size andcan be placed easily on lap.

Handheld Computers (like smart phone) are also potable. Handheld computer is also known as palmtop

computer. It easily fits in the hand of the user.

Uses of Micro Computer

The PC is the most common type of computer used in the office. It is now widely used in many homes.


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These are also used for business and engineering application.

2. Mini Computers

Mini computers were introduced in the 1960s. Minicomputer is larger and more powerful computer than

personal computer. It can execute five million instructions per second. It generally consists of two or more

processors.

Mini computer can serve up to 4000 connected users simultaneously. It is normally accessed by users via

personal computer or terminal. A device with a monitor and keyboard is called terminal. It is also known as

dumb terminal. It has no processing power and cannot work as stand-alone computer. Examples of mini

computers are:

VAX-8800

AS 400.

Uses of Mini Computers

Mini computers are often used by small and medium-sized companies to provide centralized store of

information.

3. Mainframe Computers

Mainframe computers were introduced in 1975. A mainframe computer is a very large computer in size. It is

more powerful than mini computer. It consists of multiple processors. It is designed to perform multiple

tasks for multiple users at the same time. Mainframe computers can serve up to 50,000 users at the same

time.

The users access a mainframe computer through terminal or personal computer. A typical mainframe

computer can execute 16 million instructions per second. Examples of mainframe computers are

NEC 610

DEC 10Uses of Mainframe Computers

Mainframe computers are used in large organizations. For example, airlines use these computers for ticket

reservation system.

4. Super Computers

Super computers were introduced in 1980s. Super computer is the fastest computer. Super computer is the

biggest in size and the most expensive in price than any other computers.

It is the most sophisticated, complex and advanced computer. It has a very large storage capacity. It can

process trillions of instructions in one second. Super Computer is the fastest and most powerful computer of

a time. Supercomputers are very expensive. Supercomputers are used for highly calculation-intensive tasks.

Super computers are used for specialized applications that require immense amounts of mathematicalcalculations..

Uses of Super Computers include:

1. Weather forecasting,

2. animated graphics like in Hollywood movies,

3. fluid dynamic calculations,

4. nuclear energy research,

5. space science

6. Weapon and missile design etc.

Examples of super computers are CRAY-XP, ETA-10.

What are Different Types of Computers?


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Ans: Computers can be divided into the following 3 types on the basis of their workingmechanism:

1) Analog Computers

2) Digital Computers

3) Hybrid Computers

1. Analog Computers

Analog computer is used to measure continuous values. It measures a physicalproperty like voltage, pressure, speed, time and temperature. An analog computertakes input in analog form and gives output in analog form.Its output is usually displayed on a meter or scale. Analog computer has low memoryand fewer functions. Analog computer is mainly used in the field of engineering andmedicine. Examples include:

Examples of Analog Computers include:

1. Thermometer2. Speedometer3. Analog clock

2. Digital Computers

A digital computer works with digital data. Digital computer uses binary numbersystem. Binary number system consists of only two digits 0 and 1. A digital computerrepresents data in digital signals. A 0 represents OFF and a 1 represents ON. Digitalcomputer performs arithmetic and logical operations on data. It gives output in digitalform.Digital computers are very fast. These computers can store results. They have largeMemory(that is data storing capacity). Today most of the computers used in officesand homes are Digital computers.Examples:

1. Personal Computer-(also called PC or Micro Computer)2. Digital Score board3. Digital watch

3. Hybrid Computers

A hybrid computer is a combination of both analog and digital computer. Hybridcomputer can handle both analog and digital data. A hybrid computer combines thebest characteristics of both the analog and digital computer. It can accept data inboth analog and digital form.Examples:

1. Hybrid computer devices are used in hospitals that may calculate patient's heartfunction, temperature and blood pressure etc.2. Hybrid computers are also used in spaceships and missile system.3. Hybrid Computer Machines are generally used in scientific applications


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4. Hybrid computers are used for controlling industrial processes.

6. Define operating system? Explain the functions of operating system?Ans:

Operating system is a platform between hardware and user which is responsible for the management and

coordination of activities and the sharing of the resources of a computer. It hosts the several applications

that run on a computer and handles the operations of computer hardware.

There are different types of operating systems. These are as follows:

1. Real-time Operating System: It is a multitasking operating system that aims at executing real-time

applications.

2. Multi-user and Single-user Operating Systems: The operating systems of this type allow a multiple

users to access a computer system concurrently.

3. Multi-tasking and Single-tasking Operating Systems: When a single program is allowed to run at a

time, the system is grouped under a single-tasking system, while in case the operating system allows the

execution of multiple tasks at one time, it is classified as a multi-tasking operating system.

4. Distributed Operating System: An operating system that manages a group of independent computers

and makes them appear to be a single computer is known as a distributed operating system.

5. Embedded System: The operating systems designed for being used in embedded computer systems are

known as embedded operating systems

Various services performed by operating systems are discussed below.

1. Process Management

CPU can perform one task at one time. If there are many tasks, operating system decideswhich task should get the CPU first. Operating system also maintains a queue of jobs forprocessing one by one.

2. Main Memory Management

Operating system manages memory (RAM)for many running programs. It allocates memoryarea to different programs. It de-allocates the memory area when a program is terminated. It

also manages efficient use of RAM during processing.

3. Secondary Storage Management

Operating system manages secondary storage. It manages the stored files and folders on diskin a proper way.

You can create and save files and folders, edit files, copy files, move files from one location toanother within one computer or from computer to computer, and delete files and folders etc,with the help oif operating system.

4. I/O System management

It manages Input/output operations. It controls I/O devices like mouse, keyboard, monitor and

printer etc.

5. File Management

It manages files, for example:

creation of files


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deletion of files copying of files. editing files moving of files etc.

6. Protection System

There are many processes of different users in memory at a time. So operating systemprovides protection so that no process can interfere with another process activity. Operatingsystem makes sure that each and every process performs within its own boundaries.

7. Networking

Operating system provides access to shared resources by networking system. Users canshare files and hardware resources like printer.

8. Command Interpreter system

Operating system provides command interpreter for reading and executing user commands.For example, Microsoft Windows XP provides Command Prompt to enter and execute

commands.

9. Booting

Operating system starts the computer. It checks the computer and makes it ready to work.

10. Loading and Execution

Operating system provides the facility to load programs in memory easily and then execute it.

11. Data Security

Operating system protects the data stored on the computer from illegal use, modification ordeletion.

12 Device Controlling

Operating system controls all devices attached to computer with the help of device drivers.Device driver is software that permits a computer system to communicate with a device. e.g.,device driver software for a modem comes with it on CD. We have to install device driverbefore using a device.

13. Printing Controlling

Operating System also controls printing function. If a user issues two or more print commandsat a time, it manages print queue for printing each document one by one in a propersequence.

14. Providing Interface

Operating system provides User interface to interact with the computer. User Interface maybe Graphical user interface (GUI) or Command line interface. For example, Microsoft Windows

XP provides an easy to use graphical user interface called GUI. Whereas DOS provides a

Command Line Interface called CLI.

7. Explain the block diagram of a computer with a neat diagram?

Ans:


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A computer can process data, pictures, sound and graphics. They can solve highly complicated problems

quickly and accurately.

Input Unit:

Computers need to receive data and instruction in order to solve any problem. Therefore we need to input

the data and instructions into the computers. The input unit consists of one or more input devices. Keyboard

is the one of the most commonly used input device. Other commonly used input devices are the mouse,

floppy disk drive, magnetic tape, etc. All the input devices perform the following functions.

Accept the data and instructions from the outside world.

Convert it to a form that the computer can understand.

Supply the converted data to the computer system for further processing.

Storage Unit:

The storage unit of the computer holds data and instructions that are entered through the input unit, before

they are processed. It preserves the intermediate and final results before these are sent to the output devices.

It also saves the data for the later use. The various storage devices of a computer system are divided into two

categories.

1. Primary Storage: Stores and provides very fast. This memory is generally used to hold the program being

currently executed in the computer, The primary memory is temporary in nature. The data is lost, when the

computer is switched off. In order to store the data permanently, the data has to be transferred to the

secondary memory.The cost of the primary storage is more compared to the secondary storage. Therefore most computers have

limited primary storage capacity.

2. Secondary Storage: Secondary storage to store several programs, documents, data bases etc. The

programs that you run on the computer are first transferred to the primary memory before it is actually run.

Whenever the results are saved, again they get stored in the secondary memory. The secondary memory is

slower and cheaper than the primary memory. Some of the commonly used secondary memory devices are

Hard disk, CD, etc.,

Memory Size:

All digital computers use the binary system, i.e. 0s and 1s. Each character or a number is represented by an

8 bit code.The set of 8 bits is called a byte.

A character occupies 1 byte space.

A numeric occupies 2 byte space.

Byte is the space occupied in the memory.


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The size of the primary storage is specified in KB (Kilobytes) or MB (Megabyte). One KB is equal to 1024

bytes and one MB is equal to 1000KB.

Output Unit:

The output unit of a computer provides the information and results of a computation to outside world.

Printers, Visual Display Unit (VDU) are the commonly used output devices.

Arithmetic Logical Unit:

All calculations are performed in the Arithmetic Logic Unit (ALU) of the computer. It also does comparison

and takes decision. The ALU can perform basic operations such as addition, subtraction, multiplication,

division, etc and does logic operations viz, >,


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Machine Language: It is the lowest and most elementary level of Programminglanguage and was the first type of programming language to be Developed. MachineLanguage is basically the only language which computer Can understand. In fact, amanufacturer designs a computer to obey just one Language, its machine code, whichis represented inside the computer by a String of binary digits (bits) 0 and 1. The

symbol 0 stands for the absence of Electric pulse and 1 for the presence of an electricpulse . Since a computer is Capable of recognizing electric signals, therefore, itunderstand machine Language.

Advantages of Machine Language

i) It makes fast and efficient use of the computer.

ii) It requires no translator to translate the code i.e.Directly understood by thecomputer

Assembly Language: This is another low level but a very important language inwhich operation codes and operands are given in the form of alphanumericsymbols instead of 0s and ls. These alphanumeric symbols will be known asmnemonic codes and can have maximum up to 5 letter combination e.g. ADD foraddition, SUB for subtraction, START, LABEL etc. Because of this feature it is alsoknown as Symbolic Programming Language. The language mainly helps incompiler orientations. The instructions of the Assembly language will also beconverted to machine codes by language translator to be executed by thecomputer.

Advantages of Assembly Language

i) It is easier to understand and use as compared to machine language.

ii)It is easy to locate and correct errors.

iii) It is modified easily

Disadvantages of Assembly Language

i) Like machine language it is also machine dependent.

ii) Since it is machine dependent therefore programmer should have the knowledge ofthe hardware also.

High Level Languages

High level computer languages give formats close to English language and the purpose of developing high

level languages is to enable people to write programs easily and in their own native language environment

(English). High-level languages are basically symbolic languages that use English words and/or

mathematical symbols rather than mnemonic codes. Each instruction in the high level language is translated

into many machine language instructions thus showing one-to-many translation

Ex: c,c++,java,fortran etc..


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Advantages of High Level Language

Following are the advantages of a high level language:

User-friendly

it is easier to learn. They require less time to write. They are easier to maintain. Problem oriented rather than 'machine' based. Program written in a high-level language can be translated into many machine

language and therefore can run on any computer for which there exists anappropriate translator.

Programs developed in high level language can be run on any Computer

Disadvantages of High Level Language

A high-level language has to be translated into the machine language by atranslator and thus a price in computer time is paid.

The object code generated by a translator might be inefficient Compared to anequivalent assembly language program

9. Explain the features of windows (or) Windows operatingsystem?

Ans: Windows is a GUI (Graphical User Interface) based operating system whichallows multitasking i.e. Multiple Applications can be simultaneously run in different

windows. It has many very useful features that adds to its user-friendliness. Some ofthem are

1. Desktop: Screen upon which icons, Windows etc. are displayed is known asdesktop. The windows, operating system desktop may contain background, one ormoreactive or inactive windows, taskbar, icons. - -etc.

2, My Computer: In windows, the things you have on your computer your programs,documents and data files are all accessible from one place called My Computer MyComputer is generally located at the upper left corner of the desktop

3 Icons: Icons are pictures representing windows elements like files, folders, shortcutsetc. Icons play a very important role in graphical user interface.

4. Recycle bin: Recycle Bin When we delete our files in windows, then these files aremoved, to Recycle Bin from where these can be restored if desired. To delete thesefiles permanently, we have to remove them from Recycle Bin So, Recycle Bin providesus with a second choice to restore the deleted files Recycle Bin can be opened bydouble clicking on its icon placed on the desktop.

We can delete the files immediately without moving them to recycle bin by pressingthe shift key along with the delete key

5. Windows Accessories Windows operating system comes equipped with basicaccessories like Calculator, Paint, Notepad, Wordpad etc.. Notepad can be used tocreate or edit text files that do not require formatting. Paint can be used to create,edit and view pictures. Similarly, Wordpad is a text editor used for short documents.


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6. Clipboard : Clipboard is a temporary storage space for data that is being copied ormoved. Clipboard generally stores one set of data at a time. The contents of clipboardare cleared each time you select a new set of data and choose either cut or copycommands again. However, in word 2000 you can have as many as 12 sets of datasimultaneously stored in clipboard.

11.What is window explorer? What are its various features?

Ans. Windows Explorer is a program which allows you to view all of your folders, andthe files that belong in those folders. It is divided into 2 parts. On the left side are thedives and folders. The right side shows the files and subfolders of the folder or driveyou have chosen from the left pane.

Features of Window explorer are:

Creating a folder:

(I) Select the Drive or Folder you want to create your Folder in

(ii) Right click in the right pane in the white area

(iii) Select New -

(iv) Select Folder

(v) Type in name for that Folder

Deleting a file / folder:

(i) Select the File/Folder you want to delete

(ii) Hit the Delete Key on the keyboard

(iii) Confirm Deletion

Moving/Copying files to different folders:

(i) Select the Folder you want to move or copy

(ii) To Move File : Simply drag it to the destination you want it to go to

(iii) To Copy File : Click on Edit --> Copy from the top of the screen. Then go to thedestination folder and click Edit --> Paste

Copying a file/folder to a floppy disk:

(i) Select the Folder you want to mdve or copy

(ii)Right click on the file or folder in the right pane

(iii) Select Send To .-->


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(iv)S&ect 3.5 Floppy (A)

(v) You can also drag the file to 3.5 Floppy (A:\) in the left pane.

Copying a file/folder from a floppy disk to other drive

(I) Select 3.5 Floppy (A :) in the left pane

(ii) Seiect the File/Folder youwant to copy from in the floppy drive

(iii) Drag it to your destination

Renaming a file or folder

(i) Select th File or Folder you want to rename

(ii) Right Click on it

(iii) Select Rename

(iv) Rename File

MS-OFFICE1. Explain about tables in Ms-word?

Ans:A table is a collection of rows and columns. The intersection of a row and column is called acell. The layout of a table looks like a small spreadsheet.

CREATING TABLE:

Draw Table:This feature is very useful to draw a table of your specification. To drawa table click on the Tables and Borders icon, or Table >Draw table. With the help of a


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pencil tool, a table can be drawn easily. It is easier than insert table option if you arenot sure of the required number of rows and columns.

INSERTING A TABLE:1. Click on the portion of the text, where the table must be created

2. Select Table

Insert Table3. Enter the number of columns (1 to 63) and rows (1 to 32767) click on OK4. A table will be displayed with the specified columns and rows.We can also insert a table by clicking Insert Table icon from the standard tool bar. Agrid will be displayed containing 5 columns and 4 rows. Click on the box containingthe table to specifythe number of rows and columns.

TYPING IN A TABLETo type the text or numbers in the table, move to the appropriate cell and type it.Once you have finished typing in one cell to go to the next cell press Tab key.Pressing Tab at the end of the row will move the insertion point to the next row andpressing Tab at the end of table will add a row at the bottom of table.


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Deleting a column:

Select the column to be deleted by clicking at the top of the column.

Select TableDelete columns The column will be deleted and the next column will be brought in its place.

SETTING THE ROW HEIGHT AND COLUMN WIDTH:

Table Alignment:To center or to bring the table to the right side select Center or

Right from Alignment in Row of Cell Height and width in Table menu.

Applying borders:

Borders can be applied to any part of the table or entire table. To put the borders,

select the cells (select entire table to put the borders in full) and select

FormatBorders and Shading.

Select Box (for outer border only), Grid (for inside borders only) or All (for outer and

gridline borders), select the color and width, click on OK.


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2. Explain about headers and footers in Ms-word?

Ans:

Headers and footers are areas in the top and bottom of each page in a

document.

You can insert text or graphics in headers and footers - for example, page

numbers, the date, a company logo, the document's title or file name, or the

author's name - that are printed at the top or bottom of each page in a

document.

You can work in the header and footer areas by clicking Header and Footer on

the View menu. Headers and footers appear only in print lay out view and in

printed documents.

EDITING HEADER OR FOOTERS

On the View menu, click Header and Footer.

If necessary, click Show Previous or Show Next on the Header and Footer

tool bar to move to the header or footer you want to change.

Make your changes to the header or footer. For example, revise text, change

the font, apply bold format, or apply a different font color.

When you change a header or footer, Microsoft Word automatically changes the

same header or footer throughout the document, unless the document contains

different headers or footers in a section.

Create a Header or Footer: On the View menu, click Header and Footer.

The Header and Footer toolbar is displayed and the main document content is

dimmed. Also, at the top margin you see the insertion point positioned in anarea enclosed by a nonprinting dashed line, with the word "Header", or so,

printed on it. This is the header area. The footer area is at the bottom margin.

To move to the footer area, click the Switch BetweenHeader and Footer

button.

With the insertion point positioned within the dashed line surrounding the

header, type the text you want for the header.

Do one or more of the following:Page numbers, page of pages(3 of 13) ,inserting date and time .

To enter the footer information, click the Switch Between Header and

Footer button to move the insertion point to the footer area. (You can also use


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the vertical scroll bar between the header and footer areas to scroll between the

header and footer.)

Follow steps 2 through 3 above to create the footer.

Click the Close button, or double-click the dimmed main document text, to

return to the main document when you are through.

Create a Different Header or Footer for Odd And Even Pages

1. On the View menu, click Header and Footer.The Header and Footer toolbar is displayed.

2. On the Header and Footer toolbar, click the Page Setup button.

The Page Setup dialog box is displayed.3. Click the Layout tab if it's not already selected.4. Under Headers and footers, click the Different odd and even check box,

and then click OK.5. Click the Show Previous or Show Next button to move to an even page

header or footer.6. Create the header or footer you want to appear on each even-numbered page.

Click the Switch Between Header and Footer button to switch betweenviewing the header or footer area.

7. Click the Show Next button to move to an odd page header or footer.8. Create the header or footer you want to appear on each odd-numbered page.

Click the Switch Between Header and Footer button to switch betweenviewing the header or footer area.

9. Click the Close button on the Header and Footer toolbar, or double-click thedimmed main document text, to return to the document.


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3. Explain Mail-Merge in Ms-word?

Ans: Mail Merge is used to create form letters, mailing tables, envelops, and catalogsby merging the information from two different files. Those two files are generally theMain Document and Data Source file. After creating those two files, they are mergedto get the desired result. Generally, Mail Merge is used to print multiple copies of a

particular letter addressed to many members. For example circulars, invitations etc.,MAIN DOCUMENT:The main document contains the subject matter of the letter to be printed. It cancontain text, graphic objects and fields, which are to be inserted into the letter. Whenmerging, data will be merged with in the main document. Therefore, the format of theletter and where the data from data source file must be inserted is specified in themain document.DATA SOURCE:Data source file contains the information in the form of records, which is inserted tothe maindocument. In one record, one members information is stored - for example, one

persons address. The individual information of the record is called a field. Actually,the data written in these fields will be inserted in the main document during merge.Mere requires 3 steps:1. Creating Main Document2. Creating Data Source


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3. Merging of two filesCREATING MAIN DOCUMENT

First, open a new document to create a main document by selecting File---

New.Then select

Tools-----Mail Merge.The following dialog will be displayed on the screen.

Click on the button Create to display the available formats (form letter, mailinglabels, envelop or catalog) of the main document. The following list will be

displayed.

From the list click on Form Letters.Then, a dialog will be displayed prompting

where to create the main document (whether in the active window (current file)

or in a new document). Click on Active Window

The Edit button will be displayed to the right of Create. Before selecting edit theMaster Document, specify the address of members to whom the letters must besent.

Creating Data Source:The address must be stored in the data file. To create the data file, click on Get Data in DataSource. The following list will be displayed.

Click on create Data Source to specify the fields (items) to be included in theaddress, like name, place etc., The existing field names will be displayed on thescreen to the right. Unwanted fields can be removed by clicking on the fieldname and by clicking on the button Remove Field Name.

Type the field name on the left side below the Field Name and click on thebutton Add Field Name. The added fields will be displayed on the right side list.After specifying the field names, to type the contents,

Click on OK. A dialog will be displayed to specify a name for the data source.Type a name and click on save.

A dialog will be displayed asking to edit the data source or edit the masterdocument, as shown below.


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Type the details by pressing enter after typing the name, address etc. To typeother address, click on Add New button. After the typing is completed, click onOK.

Data source dialog will end and a blank screen will be displayed to type the

subject matter of the letter. Now, type the contents of the letter. Wherever the content of data source is to

be included, click

On insert Merge Field icon available in Mail Merge tool bar, a list of availablefields in the data source will be displayed.

Click on the desired field name to insert it into the file.

After typing the letter, save it under a name (do not give the name of datasource to the letter). Now the document is ready to merge. To merge the data source with the main document and to print a letter for every

address in the data source, select ToolsMail Merge. Merge dialog will bedisplayed again.

Click on Merge displayed at the bottom of the dialog. The following Mergedialog will be displayed.

By default, the merging will be done in a new document and a letter will beprinted for every address in the data source. If the letters has to be printed for afew addresses only, specify from and To for address numbers. Select Merge tomerge the addresses with the letter. A letter will be printed for each address in

the data source in a new file. These merged letters can be saved in a file andprinted later.


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4. Explain about Macros in Ms-word?Ans:A macro is a series of keystrokes and mouse clicks that can be called with thesimple click of a mouse. Advanced users of ten create and use macro to automatefrequently used operations. This provides time saving shortcuts to speed up suchoperations.

Recording macros in Word

To record a macro in Word, follow these steps:

1. Choose Tools --> Macro --> Record New Macro.

A Record Macro dialog box appears, as shown in Figure.

2. Type a name for your macro in the Macro name text box.

3. Click the Keyboard button.

A Customize Keyboard dialog box appears, it's where you assign a keystroke combination to your macro.

4. Press the keystroke that you want to represent your macro (such as Alt+F12).

You can repeat this step to assign multiple keystrokes to the same macro if you want.

5. Click the Assign button.

6. Click the Close button.

The mouse pointer turns into an arrow with an audiocassette icon; a Stop Recording toolbar appears, as

shown in Figure 3, which you can use to pause or stop recording a macro.

7. Press the keystrokes that you want to record in your macro.

If you click the Pause Recording button, you can temporarily stop the recording of your macro.

8. Click the Stop Recording button when you finish recording the keystrokes.

To run your macro, press the keystroke combination that you chose in Step 4.

********


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5. Explain about components of Ms-word Window and its features?

Ans: MS-WORD is a word processor developed by Microsoft Corporation. We can

create, edit, and print the documents according to our requirements. Some of thefeatures of Ms-WORD include mail merge, auto correct, spelling and grammarchecking, tables, etc

Components of MS-word:

Tool bar:A set of icons to perform different tasks and displayed as a set is called a tool

bar. Standard toolbar and formatting toolbars are displayed at the top of the screen

below the menu bar. In word 2000, drawing tool bar is displayed at the bottom of thescreen.

Ruler bar:It displays the margins, indents, tab positions on a numbers scale, Horizontal

ruler line will be on the top and vertical ruler line is to the left of the screen.View Bar:

View Bar is displayed below the workspace containing 4 icons in it. It can beused to display the document in Normal View, Online Layout View, Page Layout View

or Outline View.

Status Bar:The Status Bar is displayed at the bottom of Ms-Word window (above the task bar). Itdisplays


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the information about the active document such as page number, section number,number of pages, insertion point position etc.,

Features of MS-Word:i) Using word you can create the document and edit them later, as and when

required, by adding more text, modifying the existing text, deleting/moving

some part of it.

ii) Changing the size of the margins can reformat complete document or part of

text.

iii) Font size and type of fonts can also be changed. Page numbers and Header and

Footer can be included.

iv) Spelling can be checked and correction can be made automatically in the entire

document. Word count and other statistics can be generated.

v) Text can be formatted in columnar style as we see in the newspaper. Text boxes

can be made.

vi) Tables can be made and included in the text.

vii) Word also allows the user to mix the graphical pictures with the text. Graphical

pictures can either be created in word itself or can be imported from outside like

from Clip Art Gallery.

viii) Word also provides the mail-merge facility.ix) Word also has the facility of macros. Macros can be either attached to some

function/special keys or to a tool bar or to a menu.

x) It also provides online help of any option.

Ms-Power Point

1. Explain about Power point and its features?

Ans: Microsoft power point is an audio-visual tool, which is used for presentationpurposes. By using power point, the information can be represented in the form oftables.A slide is container of information. The information on the slide can be edited andanimated.

Features of Power point:1. Microsoft power point is an audio-visual tool, which is used for presentation

purposes.

2. By using power point, presentations can be made in different styles like onscreen presentations, overhead transparencies etc.

3. Power point provides auto content wizard, template features for preparing

presentations.

4. Slides can be viewed in different ways.


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5. Slides can be inserted, deleted, copied in presentations.

6. Slide numbering can be provided.

7. Power point allows adding animation effects to slide contents.

8. Music can be added while displaying a slide.

2. Create a power point presentation using auto content wizard and designtemplate?Ans: PowerPoint offers a variety of ways to create a new presentation. We can create

a presentation by the following three methods.

Using AutoContent Wizard

Using Templates

Using Blank Presentation.

CREATING A PRESENTATION USING AUTOCONTENT WIZARD:

The steps to create a presentation using AutoContent Wizard.

Select the AutoContent Wizard option from the PowerPoint dialogue box. A dialogue

box as shown in the figure will be displayed.

Click on the Next button. Enter the data in each text box and click on Next.

Choose the type of the presentation and click on the Next. A dialogue box willbe displayed that helps to select a visual style and duration of the presentation.

Make the selections and click on Next.

Select the kind of output is required and whether handouts are to be printed ornot and click on Next.

Click ON Finish to conclude the wizard.

CREATING A PRESENTATION USING TEMPLATE A presentation template is a saved presentation file that contains predefined

slide and title

Masters, color schemes and graphic elements. It also includes masters withpreformatted fonts and styles.


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The steps to apply a template to a new presentation are:

Select the template option from the PowerPoint dialogue box.

Click on the Presentation

Designs tab to display the design templates.

Select a template and click on OK button to activate the template.

The New Slide Dialogue box will be displayed as shown in the figure. Select a layout and click on OK button

Now we can start creating the presentation by adding the information and stylesto each slide.

3. Explain working with slides?Ans:

After creation of a presentation, we can add, delete or copy slides wherevernecessary.

Adding a SlideThe steps to add a slide are: Select the New Slide option from the Insert Menu. Select an appropriate layout from New Slide dialogue box. Click on OK.

Deleting a SlideThe steps to delete a slide are: Select the slide to be deleted. Select Delete option from Edit Menu.

Copying a SlideThe steps to copy a slide are: Open the presentation in Slide Sorter View. Select the Slide, which we want to copy. Place the cursor where we want to insert the slide.

Select Edit Paste.

4. Explain about drawing objects in power point?Ans: The drawing feature in PowerPoint helps to draw shapes such as rectangles,squares, circles and even stars on a slide.

DRAWING RECTANGLE AND ELLIPSE:The steps to draw a rectangle are: Click on the Rectangle tool icon in the Drawing Toolbar. The mouse pointer changescrosshair. Move crosshair pointer to the position on the slide where we want to start therectangle. Click and drag the pointer to the opposite corner for the rectangle. Release the mouse button.The steps to draw an ellipse are: Click on the Ellipse tool icon in the Drawing Toolbar. The mouse pointer changes to

crosshair. Move crosshair pointer to the position on the slide where we want to place the edgesof the ellipse. Click and drag the pointer until the ellipse shape and size we want. Release the mouse button.


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DRAWING LINES AND ARCSDrawing Lines and Arcs is similar to that used for drawing shapes, except that Lineand Arc are not enclosed objects. The Line and Arc have a beginning point and en endpoint with resize handles at each point.

The steps to draw a Line are:

Open the slide we want to draw a Line.

Click on the Line icon tool in the Drawing Tool bar. The mouse pointer changestoCross hair.

Move the crosshair to the slide and point where the Line begins.

Click and drag the mouse to the endpoint of the Line.

Release the mouse button.The steps to draw an Arc are:

Open the slide we want to draw an Arc.

Click on the Arc icon tool in the Drawing Tool bar. The mouse pointer changes toCross hair.

Move the crosshair to the slide and point where the Arc begins.

Click and drag the mouse to the endpoint of the Arc.

Release the mouse button.

DRAWING AUTO SHAPES:

The AutoShapes feature makes it easy to draw frequently drawn shapes in PowerPointslides and other applications. The AutoShapes tool displays a popup menu click on it.

It contains objects like Lines, Basic Shapes, Block Arrows, Flowcharts, Stars, Bannersand Callout.The steps to draw an AutoShape are:

Click on the AutoShape on the drawing Toolbar.

The AutoShape popup menu will be displayed. Select a tool and move thepointer to

the slide.

Click the pointer to anchor the beginning point and drag to the end point for theobject.


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MS-EXCEL

Explain about cell references in Excel?Ans:


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Computer Science 2010

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