Computer Notes MFS Booklet Class 9th.compressed

IX-Computer Chapter # 1 Page # 51

(68) Main-Frame computer is also called______________.

(a) Minis (b) Macro computer

(e) Super Computer (d) Micro computer

(69) Low level language was developed in____________ generation of computer.

(a)1st (b) 2nd (e) 3rd (d) 4th

(70) ______________ Generation is called generation of artificial intelligence.

(a) Third (b) First (c) Second (d) Fifth

(71) Disk Oriented Computers were introduced in____________ generation of

computer.

(a) 3rd (b) 5th (e) 4th (d) 2nd

(72) A set of Eight Bits is called______________.

(a) Nibble (b) Word (c) Byte (d) None of the above

(73) The physical structure of the computer is called____________.

(a) Hardware (b) Software (e) Manware (d) All of above

(74) The physical or tangible components fanning a computer are
called__________.
(a) Software (b) Hardware (e) Firmware (c) Live ware

(75) A____________ is a set of instructions that causes a computer to function in a
desired way.

(a) Software (b) language (c) Program (d) None of the above

(76) An /A___________ translates a program into Machine Language, one line at a

time.

(a) Compiler (b) interpreter (c) Assembler (d) None of the above

(77) A program is a set of step by step instruction while a set of computer
programs is Called___________.
(a) Firmware (b) Hardware (c) Software (d) Live ware

(78) ___________translator translates the whole high level language program into
machine language at once.
(a) Compiler (b) Interpreter (e) Assembler (d) None of the them

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CHAPTER-2
COMPUTER COMPONENTS

CLASS-IX

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COMPUTER COMPONENTS

Contents

2.1 Components of Computers
2.2 Data Processing Cycle
2.3 Elements of an E.D.P System
2.4 The Central Processing Unit (CPU)
2.5 The Mother Board
2.6 The Microprocessor Chip
2.7 Buses
2.8 Ports
2.9 Memory and its types
2.10 Functions of input devices
2.11 Functions of output devices
2.12 Exercise
2.13 Questions from Past Papers

2.14 Multiple Choice Questions (MCQs)

FUNCTIONAL COMPONENTS OF COMPUTER:

 The various functional components of a computer are:

* Input devices * Central Processing Unit

* Output devices * Storage devices

 The Input and Output devices attached to a computer are called
computer peripherals.

COMPUTER PERIPHERALS:

A computer system consists, of Hardware and Software Hardware is the
physical component of computer system. Software are adds logic decision
making and data processing power to the computer.

1.2. COMPONENTS OF COMPUTERS:

All the input, output, processing and storage devices are classifieds
peripherals. The word peripheral comes from periphery, which means at the
edge or border. In computer terminology, peripherals are devices which are
connected to the-motherboard. The peripheral devices comprise:

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 Input devices
 Output devices
 Storage devices

 Input devices:

Input devices are used to input data and instructions to the computer.

The data can be the form of alphabets, numbers, images, etc. Examples of

input devices are Keyboard, Mouse, Trackball, Joystick, Light Pen, Scanner,

Microphone, Digital Camera etc.

 Output devices:

To receive the result of work done by the computer, we need output

devices. An output given by the computer can be in the form of a display on the

screen or a printed document. Most of the output devices are commonly used

at home and offices.

Examples of output devices are Monitor (VDU), Printer, Plotters, Speakers,
Projectors etc.

 Storage devices:

To store data, programs etc. you need secondary storage like floppy
disk, hard disk, computer disk, DVD magnetic tape, etc. Along with
secondary storage media, we also need storage devices to read from and,
write to the corresponding media for example, a floppy disk is a storage
medium while a Floppy drive is it device.

 REASONS TO USE COMPUTER SYSTEMS:

Some reason to use the computer system:

 Computers can work much faster than humans.
 Computers never get tired or need a rest.
 Computers can do jobs that would be dangerous form a human to do.
 Computers can store large amounts of information a very small space.
 Computers can find information very quickly.
 Computers never lose or misplace information.

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2.2 DATA PROCESSING CYCLE

When ever a computer is used, it must work its way through three
basic stages before any task can be completed. These are input, processing
and output. A computer works through these by running a program. A
program is a set of step-by-step instructions, which tells the computer
exactly what to do with -input in order to produce the required output.
Data Processing Cycle consist in three basic steps Input Process and
Output.

STEPS OF DATA PROCESSING CYCLE

(i) INPUT:-

The input stage of computing is concerned with getting the data
needed by the program into the computer. Input devices are used to do
this. The most commonly used input devices are the mouse and. the
keyboard.

(ii) PROCESS:-

The program contains instructions about what to do with the input.
During the Processing stage the computer follows these instructions using
the data, which has just been input. What the computer produces at the
end of this stage the output will only be as good as the instructions given in
the-program. In other words if garbage has been put into the program,
garbage is what will come out of the computer. This is known as GIGO or
garbage in garbage out .

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(iii) OUTPUT:-

The output stage-of computing is concerned with giving out
processed data as information in a form that is useful to the user, Output
devices are used to do this. The most commonly used output device is the
screen, which is also called monitor or Visual Display Unit (VDU) and the
printer.

TYPES OF DATA PROCESSING:-

There are four types of data processing.
1. Manual Data Processing
2. Mechanical Data Processing
3. Electronic Data Processing.
4. Electro-Mechanical Data Processing

1. MANUAL DATA PROCESSING:-

It means to process data manually, that is by hands with the help of
pen, pencil and paper. No mechanical, electrical or electronic devices are used
in this process.

2. MECHANICAL DATA PROCESSING:-

It means processing data on any mechanical machine where no such
electrical power or device is used.
Example: - Manual typewriter.

3. ELECTROMECHANICAL DATA PROCESSING:-

If electricity is supplied to a machine as a source of power to process
data then it is termed as electromechanical data processing.

4. ELECTRONIC DATA PROCESSING:-

When a machine works with the help of movement of electrons and
process on a data then this processing is known as Electronic Data Processing.
In this processing a set of instructions is given to compute a specified result by
any electronic device.

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2.3 ELEMENT OF AN E.D.P SYSTEM

The elements of an EDP system are following:-

1. Hardware
2. System Software
3. User Program
4. Procedure
5. Personals

1- HARDWARE:

In E.D.P system the term hardware means all the equipment's machines
or devices used in performing different tasks.

OR
Hardware means equipment that performs the following functions in a
data processing system.
(a) Input to computer
(b) Controls
(c) Primary storage
(d) Secondary storage
(e) Output from computer

2- SYSTEM SOFTWARE:-

It means operating system programs and routines, which control the

movement of information in the computer. It makes easy for us to create and

manage data in its subsequent parts or forms on our computer.

3- USER PROGRAMS:-

User programs are those programs, which are used in data processing

system to perform any particular task or application to solve any problem

according to user's requirements.

4- PROCEDURE:-

In the procedure the input data are changed and usually combined with

other information, to produce data in more useful form. A data processing

procedure normally consists of a number of basic processing operations

performed in some order.

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(a) Recording (b) Duplicating (c) Verifying
(d) Classifying (e) Sorting

(a) RECORDING:-

Recording refers to the transfer of data into some form of document.

(b) DUPLICATING:-

This operation involves it production of the data into many forms of

documents. Duplicating may be done while the data are being recorded

manually, or it may be done afterwards by some machine.

(c) VERIFYING:-

Since recording is usually a manual operation, it is important that
recorded data must be carefully checked for any errors. This operation is called
verifying.

(d) CLASSIFYING:-

This operation separates data into various categories.

(e) SORTING:-

Arrangement of data into specific order is called sorting.

5- PERSONALS:-

The following personal are related with computer.
(a) Computer operators
(b) Computer programmer
(c) System analyst
(d) Computer maintenance personnel
(e) Sales personnel

(a) COMPUTER OPERATORS:-

Computer operator handles the devices that feed data into and out of

the computer. They are also responsible for keeping the logbooks and other

paperwork related to these devices and for the supplies used with these

devices.

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(b) COMPUTER PROGRAMMER:-

Computer programmers are mainly responsible for writing programs for
the computer. Computer programming is a very technical field. Programmers
usually have college degree in computer science or in related field.

(c) SYSTEM ANALYST:-

System analysts are responsible for the overall flow of information
among the various departments. Working directly under the management,
they organize the various data processing procedures throughout the
department and guide the programmers as to the type of programs to be
written. A system analyst usually has a graduate degree in computer science
or business management. Skilled analysts are in great demand and are highly
paid.

(d) COMPUTER MAINTENANCE PERSONNEL:-

They are responsible for onsite servicing of computer hardware. They
are highly trained at engineering colleges or universities.

(e) SALES PERSONNEL:-

Computer sales personnel usually have college degree and have good
knowledge about computer. The ability to interact in a positive manner with
people is an essential requirement for successful salesmanship. There is a great
demand for capable sales representatives.

2.3 THE CENTRAL PROCESSING UNIT (CPU):- (2008)

CPU is also called the brain of computer system because in this major
unit searching and sorting of data, calculating and decisions making goes on,
but this is not really true because computers are not able to think themselves.
It is also called the nerve centre of computer system. It is a place where data is
transformed into meaningful information. It contains the Main-memory,
control unit and "Arithmetic and Logic unit". The main memory holds the
program instructions and data. It has two types of Main Memory chips, called
RAM and ROM.

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 MAIN UNITS OF CPU:- (2011, 2008)

There are four main units of C.P.U.

(a) Control unit. (C.U)

(b) Arithmetic and Logic Unit (A.L.U)

(c) Main Memory or Memory Unit (M.U)

(d) Registers.

 MAJOR UNITS / TYPICAL COMPONENTS OF (C.P.U):-

There are two typical major components of a CPU

(a) Control Unit (b) Arithmetic and Logic Unit

(a) CONTROL UNIT (C.U):-

It controls time and sequence of operations of computer. It works like a

traffic police man directing the flow of data between the components of the

CPU and to and from the other devices. The control unit directs and

coordinates all activities of the computer including the following.

 FUNCTIONS OF C.U:-

1. Controls the input/output devices.
2. It stores and retrieves the data from memory.
3. It retrieves the data from storage devices.
4. It routes of information between memory and Arithmetic Logic Unit.
5. It Controls the direction of arithmetic and logical operations.
6. It Controls the execution of program.

(b) ARITHMETIC AND LOGIC UNIT (A.L.U):

The arithmetic Logic Unit performs actual processing of data, which

includes addition, subtraction, multiplication and division. This unit also

performs certain logical operations such as comparing two numbers to see if

one is greater than the other or is they equal, in this way computer is able to

make simple decisions.

(c) MAIN MEMORY:

Every computer has a main memory where data and instructions which
are currently being processed, are stored main memory is wholly electronic, fast
and reliable. Its nearness to the rest of the central processing unit (CPU) and
the great speed at which it can be accessed mean that it is sometimes called
immediate access storage.

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(d) REGISTERS:-

As each instruction is interpreted and executed in the CPU, there is a lot
of movement of information. The information is retained temporarily on a
number of special memory units called registers. These registers are not part of
the main memory. There are 14 basic registers shared by ALU and being
processed is stored in registers, each one designed to perform a specific
function. Thus registers receive the information, hold it temporarily, and pass it
on as directed by the control unit.

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2.4 THE MOTHER BOARD:

The motherboard, or system board, is the main circuit board in the
system Unit. The motherboard consists of a flat board that fills one side of the
case. It contains both soldered, non-removable components and sockets or
slots for components that can be removed microprocessor chip, RAM chips,
and various expansion cards.

EXPANSION:-

Expansion is a way of increasing a computer's capabilities by adding
hardware to perform task that are beyond the scope of the basic system. For
example, you might want to add Video and Sound cards. Upgrading means
changing to newer, usually more powerful or sophisticated versions, such as a
more powerful microprocessor or more memory chips.

2.6 THE MICROPROCESSOR CHIP:

The most fundamental part of the motherboard is the microprocessor
chip as mentioned, a microprocessor is the miniaturized circuitry of a
computer processor. It stores program instructions that process, or
manipulate, data into information.

Two principal "architectures" or designs for microprocessors are ClSC and
RISC.

 CISC (COMPLEX INSTRUCTION SET COMPUTING):-

CISC (Complex Instruction Set Computing) chips, which are used mostly
in PCs and in conventional mainframes, can support a large number of
instructions.

 RISC (REDUCED INSTRUCTION SET COMPUTING):-

RISC (Reduced Instruction Set Computing) chips, which are used mostly
in workstations, a great many seldom-used instructions are eliminated.

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 INTEL-TYPE CHIPS FOR PCs:

About 90% of microcomputers use Intel-type micro-processors. Indeed,
the Microsoft windows operating system is designed to run on Intel chips.

 EXPANSION CARDS:-

Also known as expansion board, adapter cards, interface cards, plug-in
board. Controller cards, add-ins, or add-ons are circuit boards that provide
more memory or that control peripheral devices. There are three expansion
buses to be aware of are ISA, PCI and AGP.

 ISA BUS- FOR ORDINARY LOW-SPEED USES:

The ISA (Industry Standard Architecture) bus is the-most widely used
expansion bus. It is also the oldest and, at 8 or 16 bits, the slowest at
transmitting data, though it is still used for mice, modem cards and low-speed
network cards.

 PCI BUS- FOR HIGHER SPEED-USES:

The PCI (Peripheral Component Inter-connect) bus is a higher- speed
bus, and at 32 or 64 bits wide it is over four times faster than ISA buses. PCI is
widely used to connect graphics cards, Sound cards Modems and high-speed
network cards.

 AGP BUS-FOR EVEN HIGHER SPEEDS AND 3D GRAPHICS:

The AGP (Accelerated Graphics Port) bus transmits data at even higher
speeds and was designed to support video and three-dimensional (3D)
graphics. An AGP bus is twice as fast as a PCI bus.

MOTHER BOARD

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2.7 BUSES:- (2014, 2011, 2008)

An internal pathway along which signals are sent from one part of the
computer to another. Buses are the set of wires that connect the different
components in the C.P.U. Buses or bus lines are electrical data roadways
through which bits are transmitted within the CPU and between the CPU and
other components of the motherboard. Address, data and control commands
all flow along the system bus through separate paths called the ADDRESS BUS,
the DATA BUS and the CONTROL BUS respectively.

 TYPES OF BUSES:-
There are three types of Buses used in CUP.

(a) Data Bus
(b) The Address Bus
(c) The Control Bus

(a) DATA BUS:-

The data bus sends data back and forth between the memory and the
microprocessor. The number of wires in the bus affects the speed at which
data can travel between components. Since each wire can transfer one bit
data at a time therefore an 8-wires bus can move 8 bits or one byte at a time.
A 16 bit bus can transfer 2 byes at a time and so on.

(b) THE ADDRESS BUS:-

An address bus connects the CPU with the memory. The address bus
identifies which memory location will come into play. That is found in every
microcomputer the address bus is important is that the number of lines in it
tells the maximum number of memory addresses. For example, 8 bit data is
enough to represent 28 = 256 different values. Thus a CPU with 8 bit address
bus could address only 256 bytes of memory.

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(c) THE CONTROL BUS:-

The control bus carries the control unit's signals. It control the
activities of all other units of the system. Control unit directs the transfer of
data from main memory to arithmetic and logic unit (ALU) for processing.
The control bus provides a two-way: transfer of data, instructions and
results between the main memory and secondary storage.

1.8 PORTS:- (2011., 2009;. 2008)

A port is a connecting socket or jack on the outside of the system unit

into which are plugged different kinds of cables. A port allows you to plug in a

cable to connect a peripheral device, such as a monitor, printer or modem, So

that it can communicate with the computer system.

 TYPES OF PORTS:-

There are two types of ports namely.

1. Serial Ports 2. Parallel Ports

1. SERIAL PORTS:-

Serial ports are used for transmitting slow data over long distances A
line is connected to a Serial Port will send bits one at a time, one after another,
like cars on a one line highway. Because individual bits must follow each other,
a serial port is usually used to connect devices that do not require fast
transmission of data, Such as keyboard, mouse, monitors, and modems. The
standard for PC serial ports is the 9 Pin or 25 Pin. It is also called the male
connector.

2. PARALLEL PORTS:-

Parallel Ports are used for transmitting fast data over short distance. A
line is connected to a Parallel Port allows 8 bits (1 byte) to be transmitted
simultaneously, like cars on an eight-lane highway. Parallel lines move
information faster than serial lines do, but they can transmit information
efficiently only up to 15 feet Thus, Parallel Ports are used principally for
connecting printers or external disk or magnetic tape backup storage devices. A
Parallel Port, also called female connector, has 25 holes, and the cable that
plug into it has 25 pins.

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2.9 MEMORY:-

Memory is a storage devices inside the computer where data /

information programs can be stored.

TYPES OF MEMORY:-

There are the following two types of memory.

(1) Internal/Primary / main memory
(2) External/Secondary / Auxiliary memory.

1. INTERNAL MEMORY:-

It is a set of chips located on the another board close to the micro-

processor. It is faster form of memory.

2. EXTERNAL MEMORY:-

External memory is a non-volatile memory that is used to store data on

permanent basis. It is slower form of memory.

2.10 FUNCTIONS OF INPUT DEVICES:-

(1) It is used to pass information into the memory unit of the C.P.U

(2) It Converts letters, numbers and other symbols into the binary
patterns.

2.11 FUNCTIONS OF OUTPUT DEVICES:-

(1) The major function of output devices is to convert data expressed in

electronic impulses to human understandable forms.

(2) These devices are used to produce final results.

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EXERCISE

Q No.1 Define the following terms with their major function.
(a) Arithmetic and Logic Unit (A.L.U) (b) Control Unit (C.U)

Ans.(a) ARITHMETIC AND LOGIC UNIT (A.L.U):-

The Arithmetic Logic Unit performs actual processing of data,

which includes addition, subtraction, multiplication and division. This unit also

performs certain logical operations such as comparing two numbers to see if

one is greater than the other or is they equal, in this way computer is able to
make simple decisions.

(c) CONTROL UNIT (C.U):-

It controls time and sequence of operations of computer. It

works like a traffic police man directly the flow of data between the

components of the CPU and to and from the other devices. The control unit
directs and coordinates all activities of the computer including the following:-

1. Controls the input/output devices.
2. It stores and retrieves the data from memory.
3. It retrieves the data from storage devices.
4. It routes of information between memory and Arithmetic Logic Unit.
5. It Controls the direction of arithmetic and logical operations.
6. It Controls the execution of program.

Q No.2 Define the term Bus in general, what are the purposes of Data
Bus, Address Bus and control Bus?
Ans.
BUSES:-

An internal pathway along which signals are sent from one part

of the computer to another Buses or bus lines are electrical data roadways

through which bits are transmitted within the CPU and between the CPU and

other components of the motherboard. Address, data and control commands

all flow along the system bus through separate paths called the ADDRESS BUS,

the DATA BUS and the CONTROL BUS respectively.

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 DATA BUS:-

The data bus sends data back and forth between the memory and the
microprocessor: The number of wires in the bus affects the speed at which data
can travel between components. Since each wire can transfer one bit data at a
time therefore an 8-wires bus can move 8 bits or one byte at a time. A 16 bit
bus can transfer 2 byes at a time and so on.

 THE ADDRESS BUS:-

An address bus connects the CPU with the memory. The address bus
identifies which memory location will come into play. That is found in every
microcomputer the address bus is important is that the number of lines in it
tells the maximum number of memory addresses. For example, 8 bit data is
enough to represent 28 = 256 different values. Thus a CPU with 8 bit address
bus could address only 256 bytes of memory.

 THE CONTROL BUS:-

The control bus carries the control unit's signals. Control unit directs the
transfer of data from main memory to arithmetic and logic unit (ALU) for
processing. The control bus provides a two-way transfer of data, instructions
and results between the main memory and secondary storage.

Q No.3 Differentiate: RAM and ROM.

Ans

RAM ROM

1. RAM stands for Random Access 1. ROM stands for Read Only

Memory Memory.

2. RAM is volatile. 2. ROM is non-volatile

3. RAM is a temporary memory. 3. ROM is a permanent memory.

4. RAM is used for user. 4. ROM is used for

manufacturers.

5. It can be changed by a user, 5. ROM is used for keeping data

or programs that are fixed

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Q No.4 what is the difference between Internal Memory and
Ans. External Memory?

INTERNAL MEMORY EXTERNAL MEMORY

1. Its cost per bit is decreasing rapidly. 1. Its cost per bit is optional.

2. Storage capacity is limited 2. Baking storage capacity is
greater.

3. Speed of internal memory is faster 3. Speed of external memory is

than external memory. not so fast

4. It is temporary memory. 4. It is Permanent memory

Q No. 5 Write the major function of Input and Output devices.
Ans.
Input Devices:-

Input devices are used to enter data into the computer. One of

the most commonly used device is the Keyboard. The Keyboard accepts data in

a form that can be understood by humans and translates it into a form that can

be read by machine.

Output Devices:-

Output devices are used to communicate the information that

has been processed by the Central Processing Unit and communicate this to the

user in human readable form.

Q No.6 Define ports compare and contrast serial ports and parallel parts.

Ans. PORTS:-

A port is a connecting socket or jack on the outside of the system

unit into which are plugged different kinds of cables. A port allows you to plug

in a cable to' connect a peripheral device, such as a monitor, printer or modem,

So that it can communicate with the computer system.

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COMPARE AND CONVERT SERIAL PORTS AND PARALLEL PORTS.

Serial Port Parallel Port

1. These ports send the 1. These ports send the information

information through a cable through parallel wires 8-bit or more

one bit at a time. at a time.

2. These ports send data slower 2. These ports send data faster than

than parallel ports. serial ports.

3. These ports are reliable for 3. These ports are reliable for

transmission data over a long transmission data over a short

distance distance.

4. These ports are also called 4. These ports are also called female

male connectors. connectors.

5. Serial ports has 9 to25 pins 5. Parallel ports has 25 holes

Q No.7 Fill in the blanks:
1. CPU is the brain of computer.
2. There are two major parts of CPU, ALU and CLU.
3. ALU stands for Arithmetic and Logic Unit.
4. Memory is the place to store data/ information/ programs.
5. There are two types of computer memory, RAM and ROM.
6. ROM is the abbreviation of Read Only Memory while RAM stands for
Random Access Memory.
7. Input devices are used to take data from user and supply it to the
computer.
8. Ports are the places that are used to connect various external devices
to the computer.
9. Serial Port is also known as male connector.

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Q No.8 Choose correct answer.
1.
2. CPU stands for

3. (a) Controlling Power Unit (b) Central Processing Unit
4.
5. (c) Central Processor Unit

6. There are______ typical components of CPU, namely_________.

7. (a) Two, arithmetic & logic unit and control unit.

Q No.9 (b) Three, ALU, CU and External storage
1.
2. (c) Two, arithmetic & logic unit and memory
3.
4. There are basically________ registers.

5. (a) Fourteen (b) Eight (c) Sixty Five (d) None
6.
Bus is a set of_______ that is used as a communication pat.
7.
8. (a) Wires (b) Processors (c) Register

There are__________ buses, namely_______________.

(a) Two, control bus, connecting bus

(b)Three, Address bus, data bus and control bus

(c) Three, Address bus, data bus and communication, bus

(d) None of above

A Part or interface that can be used for communication, in which

only 1 bit is transmitted at a time, is called______________.

(a) Serial Port (b) Parallel Port

(c) None of above (d) Serial and Parallel port both transmit 1 bit

Which port is reliable?

(a) Serial (b) Parallel

(c) Both are equally reliable (d) None of above

Choose the correct statement - True and False.

The CPU is housed in a single chip called a microprocessor.

(a) True (b) False

The ALU performs arithmetic and logical operations.

(a) True (b) False

Registers are non-volatile memory.

(a) True (b) False

RAM stands for Random access memory and it is a permanent

memory.

(a) True (b) False

RAM is also referred to as Primary memory.

(a) True (b) False

A port is socket at the back of a computer used to plug-in

various devices.

(a) True (b) False

A serial port has 9 or 30 pins.

(a) True (b) False

Parallel port sends data faster but a serial port is much faster.

(a) True (b) False

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QUESTIONS FROM PAST PAPERS:

YEAR 2014:

Section "A" (Multiple Choice Questions) - (MCQs)

(i) Output Displayed on screen is called:

* Softcopy * Software * Live ware * Hardcopy

(ii) Which is more reliable among these?

* Serial * Parallel * Buses * All of these

Section "B" (Short -Answer Questions)

Q No.9 Define bus. How many types of bus are there? Write down the

names only.

Section "C" (Detailed-Answer Questions)

Q.15 (a) Draw a block diagram of CPU and explain the following parts:

(i) AL U (ii) Control Unit

YEAR 2013:

Section "A" (Multiple Choice Questions) - (MCQs)

(xi) BUS is a set of: * Virus * Ports * RAM
* Connectors

Section "B" (Short -Answer Questions)
Q.I0 Write down briefly the functions of C.P.U.
Q.14 Define Register. How many Registers are there in C.P.U?

Section "C" (Detailed-Answer Questions)
(No Questions)

YEAR 2012:

Section "A" (Multiple Choice Questions) - (MCQs)

(xv) Set of wires which are used as the communication path:

* BUS * Port * Input device * Memory

Section "B" (Short -Answer Questions)
(No Questions)

Section "C" (Detailed-Answer Questions)
(No Questions)

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Section "A" YEAR 2011:
(iii)
(Multiple Choice Questions) - (MCQs)
The Screen output which is intangible and temporary refers to:
* Softcopy * Hardcopy * Source Code * Object Code

Section "B" (Short Answer Questions)

Q No.6 Define Ports and describes its types.

Section "C" (Detailed-Answer Questions)
Q.15(b) Draw block diagram of CPU and describe its different
components.
Q.16(b) Define the term BUS. Write its types in detail.

Section "A" YEAR 2010:
(iii)
(Multiple Choice Questions) - (MCQs)
(v) A port which transmits only 1 bit of information at time is called:
* Serial Port * Parallel Port * Both Ports * None of these

Bus is a set of: * Ports * RAM
* Connectors * Wires

Section "B" (Short -Answer Questions)
(No Questions)

Section "C" (Detailed-Answer Questions)

Q.3. (a) Define CPU with a diagram and describe its major parts .

YEAR 2009:

Section "A" (Multiple Choice Questions) - (MCQs)
(vi)
____________ is the place that is used to connect various
(vii)
external devices to the computer:

* USB * Serial *parallel * Port

____________port is also known as male connector:

*Serial *Parallel *Equal *Non of the above

Section "B" (Short -Answer Questions)
(v) Define a Port and describe its types

Section "C" (Detailed-Answer Questions)

Q.3 (b) Draw a block diagram of CPU and define the following terms

with their major functions.

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Q.2(a) YEAR 2008:
Q.3(a)
Define ports and give its types.
Q.4(b) Define a Bus. What are to be purpose of Address bus, Control bus
and Data bus.
Define CPU? What are the main units of a CPU? Explain each
unit with the help of a block diagram.

MULTIPLE CHOICE QUESTIONS (MCQs)

(1) In computer term 16 KB means: (2012)

(a) 16000 (b) 16384 (c) 1000 (d) 256

(2) Pre programmed memory is:
(a) SRAM (b) DRAM (c) DIMM (d) None of them

(3) ____________unit interprets the instruction and sends command to

the various parts of CPU.

(a) ALU (b) CU (c) Memory (d) None of the above

(4) Mathematical calculation is carried out by of CPU.

(a) CU (b) ALU (c) MU (d) None of the above

(5) The manipulation of data into more useful form is called___________.

a) Data Processing (b) Information

(c) Data (d) None of the above

(6) _________________ controls and supervises all computer activities.

(a) ALU (b) CU (c) MU (d) None of the above

(7) ____________is responsible for mathematical calculations.

(a) CU (b) ALU (c) MU (d) None of the above

(8) _____________ unit is used to store data.

(a) ALU (b) CU (e) MU (d) None of the above

(9) ______________is/are the place that is/are used to connect various
external devices to the computer.

(a) Ports (b) Buses (c) CPU(d) None of the above
(10) _________ port is also known as male connector.

(a) Serial (b) Parallel (c) Both are (d) None of the above

(11) The processing unit responsible for mathematical computation is

called_____.

(a) ALU (b) CU (c) MU (d) None of tile above

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(12) A Kilo Byte is equal to__________ Bytes.

(a) 1024 (b) 24 (c) 100 (d) 8

(13) The volatile part of memory is called____________.

(a) RAM ( b) PROM (c) ROM (d) None of tile above

(14) ____________ Bytes = 1 Kilo Byte.

(a) 1024 (b) 100 (c) 8 (d)4

(15) 8 BITs =__________ Byte

(a) 1 (b) 2 (c) 4 (d)8

(16) _________________controls the overall communications and makes the

computer to carry out program instructions in the correct order.

(a) ALU (b) CU (c) MU (d) CPU

(17) _________________ performs arithmetic and logical operations.

(a) ALU (b) CU (c) MU (d) CPU

(18) Smallest addressable unit of memory is ________________________.

(a) Bit (b) Byte (c) Word (d) Nibble

(19) _____________is a physical part of computer and used to hold largest
amount of data.
(a) Hard Disk (b) Floppy Disk (c) RAM (d) All of the above

(20) A complete electronic circuit of computer is called_________________.

(a) Microprocessor (b) Motherboard
(c) Mainboard (d) None of the above

(21) The main unit of any computing system is called _____________

(a) ALU (b) CPU (c) CU (d) MU

(22) The Control Unit, Arithmetic Logic Unit and registers are combined in a

single chip called__________.

(a) Microprocessor (b) Vacuum Tube

(c) Transistor (d) None of the above

(23) ___________are special storage areas built into microprocessor to
access data at high speed.
(a) Registers (b) ROM (c) Cache (d) None of the above

(24) ______Memory is temporarily highly accessible, high speed work area.

(a) RAM (b) ROM (c) PROM (d) None of the above

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(25) ____are the sockets at the back of a CPU used to plug - in various devices.

(a) Ports (b) Buses (c) Cables

(d) None of the above

(26) A parallel port is also called a ____________________connector.

(a) Male (b) Female

(c) Male and Female (d) None of the above

(27) A _____________port sends 8-bits or more at a time along parallel wires.

(a) Serial (b) Parallel

(c) Serial and Parallel (d) None of the above

(28) Generally, slow devices are connected with the _______________port.

(a) Serial (b) Parallel (c) None of the above

(29) The faster devices are always connected to the _______________ports.

(a) Serial (b) Parallel (c) None of the above

(30) ____ devices are used to enter data into or enter data from a system.

(a) Input (b) Output

(c) Input and output (d) None of the above

(31) _____are the set wires that are used as a communication path. (2012)

(a) Buses (b) Ports (c) Connectors (d) None of the above

(32) ______ controls all the functions of a computer.

(a) C.P.U. (b) Control unit (c) A.L.U. (d) Main memory

(33) Volatile memory is known as __________________

(a) RAM (b) ROM (c) PROM (d) REM

(34) Bus is a set of _____________ (2010)
(d) RAM
(a) Connectors (b) Wires (c) Ports

(35) A port which transmits only 1bit of information at a time is called
______. (2010)
(a) Serial Port (b) Parallel Port
(c) Both Ports (d) None of them

(36) Main memory unit of a computer __________ _
(a) Stores a small amount of data and instruction
(b) Performs mathematical operations
(c) Stores bulk of data and instruction
(d) Supervises the working of all other units

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(37) ___________bus is used by processor to select a specific memory
location with in the memory subsystem.
(a) Data (b) Address (c) Control (d) None of the above

(38) The type of memory which does not lose the stored information when

the Computer power is turned off is known as ___________ .

(a) Primary memory (b) ROM

(c) RAM (d) Permanent memory

(39) The main memory unit of a modem computer consists of __________ .
(a) Ferric cross (b) Vacuum tubes (c) Wires (d) LSI chips

(40) The main memory of a computer as compared to auxiliary memory is
_________ .
(a) Slower (b) Larger (c) Faster (d) Cheaper

(41) A register is a type ofmemory.

(a) Volatile (b) Non - volatile (c) Permanent (d) None of them

(42) Address bus connections is between the CPU and ______________
(a) Memory (b) Control unit (c) ALU (d) None of them

(43) _________ is the place that is used to connect various external devices
to the computer.
(a) USB (b) Serial (c) Parallel (d) Port

(44) ____________port is also known as male connector.
(a) Serial (b) Parallel (c) Equal (d) None of the above

(45) Pre-Programmed memory is:
(a) SRAM (b) DRAM (c) DTMM (d) None of these

(46) __________ is also called the brain of computer.

(a) CU (b) MU (c) ALU (d) CPU

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CHAPTER-3

INPUT / OUTPUT DEVICES

CLASS-IX

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INPUT / OUTPUT DEVICES

3.1 INPUT DEVICES

3.1.1 Keyboard.
3.1.2 Mouse.
3.1.3 Track ball.
3.1.4 Joy Stick.
3.1.5 Light Pen.
3.1.6 Scanners.
3.1.7 Digital Camera.
3.1.8 Micro Phone.

3.2 OUTPUT DEVICES:

3.2.1 Monitors
3.2.2 Printers.
3.2.3 Plotters.

DIFFERENCES:

1. Input devices and Output devices
2. Softcopy and Hardcopy
3. Mouse and Track ball
4. Impact and Non Impact printers
5. Printer's and Plotters
3.3 DUAL PURPOSE DEVICES
3.4 EXERCISE:
3.5 QUESTIONS FROM PAST PAPERS
3.6 MULTIPLE CHOICE QUESTIO.NS (MCQs)

3.1 INPUT DEVICES:(2012,2009)

Input devices are used to enter the data or instructions into the CPU.
With the help of these devices data can be input into the computer. For
example keyboard and mouse. These are used to pass data directly to CPU
and convert the characters letters numbers and other symbols) into binary
patterns, which can be held inside the computer memory. They translate
information of high level language into low level language so that computer
can understand it easily.

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Types of Input Devices:

There are two main types of input devices.

1. Direct Input Devices. Can input large amount of data quickly and
accurately without any need of human intention.

Bar Code Reader and Optical Mark readers are both 'examples of direct
input devices. Manual Input Devices: are used by people to enter data by
hand. The most commonly used manual input devices are the mouse
and the keyboard.

MANUAL INPUT DEVICES DIRECT INPUT DEVICES
 Keyboard
 Mouse • Optical mark recognition
 Track ball. • Magnetic ink character recognition
 Joystick • Optical character recognition (OCR)
 Light pen • Bar code
• Magnetic strip reader

 MANUAL INPUT DEVICES:

3.1.1 KEYBOARD:(2014, 2012, 2010)

Keyboard is the most commonly used primary text input device.
Keyboard is used to enter the data into the C.P.U. Ordinary computer
keyboards have their keys arranged in a similar way to those on a
typewriter. This way of arranging the keys is called QWERTY because of the
order in which the keys appear on the first, row of letters. Keyboards also
have extra keys, which can carry out different tasks depending upon the
software that being used. A standard keyboard includes about 100 keys and
each key sends a different signal to the CPU.

Keyboard Is a purely input device. When we press any key of the
keyboard the letter appears on the monitor and the corresponding ASCII
CODE activated inside the computer memory.

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Divisions Parts of Keyboard :( 2012, 2010)

Though the panel of keys on the keyboard is usually divided into five parts namely:-

1. The Alphanumeric, character keypad and typewriter key pad.
2. The Numeric keypad.
3. The Function keypad.
4. Screen Navigation, editing keys and cursor keys
5. Modifier keys.

(i) The Alphanumeric, Character keypad and typewriter keypad:

These keys are similar to a standard typewriter and are used for input

general information. This keypad can be located at the middle side of the

keyboard. Each key can be assigned in an upper case, a lower case letter or

numeral or a function.

(ii) Numeric Keypad:

These keys are used-to input numeric data only (0-9). These keys are

very useful in case of large numeric data inputs because all numeric keys can

be accessed by one' hand. These keys can also be used as an alternative. to

screen navigation, editing and" cursor keys. This keyboard looks very similar

to a type writer.

(iii) Function Keys:

The function keys on the keyboard labeled as F1 ... F12 are located at

the top or left of the keyboard. All of these keys have pre-defined functions

which depend on the software, because each function key has a different
function i diffe e t soft a e s.

(iv) Screen navigation, editing and cursor keys:

These keys are used to move the cursor on the screen on every direction

Normally, when Num Lock is off, then numeric keypad may be used as Screen

Navigation or editing keys. But in the advance keyboard these keys also present

in between the numeric keypad and typewriter keys.

(v) Modifier keys:
These keys are used to modify the input of other keys. Shifts, Ctrl, Alt,

Delete, Insert and ESC Key are the same examples of modifies Keys.

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 Pointing Input Devices:

Pointing input devices is the device which is used to move a pointer on

the computer system in order to place on a display screen and to select one or

more selections to be taken from that position.

 Some Commonly Used Pointing Input Devices:

(1) Mouse (2) Track Ball

(3) Joy-Stick (4) Light Pen

3.1.2 Mouse (2009)

A mouse is a pointing input device. It lacks the ability to transmit text
and information. It is the next most common type of input device after the
keyboard. The mouse is a hand held device with two or three buttons and is
used to move the cursor around on the screen. The buttons are used to point,
click and drag.

Pointing is when you move the mouse on a flat surface and point the
cursor anywhere on the screen Pressing the button with your finger is called
clicking to select something on the screen, double click the left button. To
select different options, click the right button. Holding down the left button as
you move the mouse is called dragging.

 Advantages of the Mouse:

 It is easy to use, with very little training.
 It enables computers to be used by non-experts in a user friendly

fashion.

 Disadvantages of the Mouse:

 It cannot be used for entering numeric or text data.
 It requires special software.
 It is not very accurate for drawing.

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3.1.3 TRACK BALL

Touch pads and trackballs are also the types of pointing input
device. They are often used instead of a mouse on portable
computers. A trackball is the modified shape of mouse. In the mouse,
the ball is on the underneath (lower side) of the mouse. While, in this
device ball is on the topside of the tracker ball passing the palm of the
hand over it moves the ball. The ball can spin in any direction with the
help of fine grooves to move cursor to a position where you want to
place it. Tracker bails are intended for use where desktop space is
limited or not available, for example, when using a laptop computer
away from a desk.

DIFFERENCES BETWEEN MOUSE AND TRACK BALL (2008)

MOUSE TRACK BALL

1) Mouse is commonly used. 1) Track ball is rarely used.

2) We have to roll it over a flat 2) We do not have to roll it over a flat
surface. surface.

3) It requires much space to use 3) It does not require much space

it. to use it.

4) We do not use a mouse by rolling 4) We use a trackball by rolling

the ball with our palm or finger, we the ball with our palm or finger.

use a flat surface.

3.1.4 JOYSTICK:

The common use of a Joystick is to play computer games by controlling
the way that something moves on the screen. Joysticks can be used to control
movement from side-to-side, up-and-down and diagonally. A Joystick can have
at least one button on it, which can be used to make something happen like
making a character in a game jump or fire a gun.

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3.1.5 LIGHT PEN: (2009):

It has the size like a normal pen. It is used to point the objects on the
screen. When the pen is closed to or touching the screen, a button on the pen
is pressed and the computer detects the position of the pen. The pen may be
used to select items from a menu, to draw lines-or standard shapes, or to
modify an existing drawing. The light pen is very easy to use but like the mouse
it cannot be used for the entry of text or numbers. The touch sensitive screen
is used in a similar way to the light pen and screen the finger is used to point
the objects or icons on the screen and to make selections from menus.

3.1.6 SCANNER:

Scanner is an input device. It can be used to scan images and text into a
computer and converts the data into digital signals. Some most common types
of scanners are. Hand-held, Flatbed scanners and sheet Fed scanners, work by
passing a beam of bright light over an image. Data is collected by sensors inside
the scanner about the amount of light reflected by the different parts of the
picture.

This data is used to produce a digital image of the picture that the
computer can display on the screen. Once the image has been scanned, it
can be saved and changed using special software. If text has been scanned
special optical character reading software must be used to convert the
digital image into real text. This conversion process is known as DIGITIZING.

 TYPES OF SCANNER:

Scanners depend on the volume and type of material to be scanned;
we can use Flatbed scanner, sheet-fed scanner and even small handheld
scanners.

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(i) Handheld Scanners:

Handheld scanners are most frequently used with microcomputers.
It is 'very small in size. Handheld scanners are less expensive, but require a
steady hand to get a clear image. These scanners are easy to use, but
sometimes they are limited to scan a wide picture.

(ii) Flatbed Scanners:

They are most versatile and commonly used scanners. They are the
stationary scanners that hold the data (image documents) in place while
the scanning mechanism passed over it. This type of scanner has a flat piece
of glass, A flatbed scanner is like a photocopying machine.

(iii) Sheet-Fed scanners:

A sheet-fed scanner looks like a small portable printer. A scanner
that feeds each, sheet of paper across a nonmoving scan head; this is
different from the flatbed scanner in which the paper is laid on a sheet of
glass and the scan head moves. This scanner' cannot be used to scan pages,
books or magazines.

3.1.7 DIGITAL CAMERA:

A digital camera can store many more pictures than an ordinary camera.
Pictures taken by using a digital camera are stored inside its memory and can
be transferred to a computer by connecting the camera to it. A digital camera
takes pictures by converting the light passing through the lens at the front into
a digital image. Pictures taken by using a digital camera can be easily saved and
transferred from one computer to another where they can be edited using
special graphics software. Special software has been used to retrieve same
pictures from a digital 'camera and saved them into the hard disk drive of a Pc.
Some digital cameras can also capture the short clips of moving images.

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3.1.8 MICROPHONE:

A microphone is used to input sound or voice into a computer system,
microphones are often used for voice recognition system which convert sounds
made by a user into commands that the computer can carry out. Systems like
this are very useful for people who can't use ordinary input devices such as the
mouse and keyboard as computer is becoming more powerful for the future,
voice recognition will be much more common input method for all computer
users.

 DIRECT INPUT DEVICES:

In this method we use look at the same methods of capturing and
entering data directly without any need for human intervention. This is
sometimes called Direct Data Entry or ODE, for short and is used When very
large amount of data need to be input quickly and accurately.

(i) OPTICAL MARK RECOGNITION (OMR):

Optical Mark Recognition or OMR, uses an input device called an optical
mark reader to detect marks made in certain places on specially printed forms.
OMR uses 'fast input method, where large amounts of data need to be input
quickly It is used to input data from things. Like answer sheets. For multiple
choice exams and registration forms in schools. The most common use of OMR
in the UK is to input data from National Lottery forms. OMR is used by the
terminal to input the numbers from the play slip so that they can be printed on
the ticket and transmitted to lottery headquarters.

(ii) MAGNETIC INK CHARACTER RECOGNITION (MICR):

Magnetic ink character recognition, or MICR, uses an input device called
magnetic ink character reader to input characters that have been printed in
special magnetic ink. Banks use MICR to process cheques. The numbers along
the bottom of a cheque are printed in magnetic ink.

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When cheques are paid into a bank the staff has to type the amounts
onto them by hand so that they can be printed on the bottom of the cheque in
magnetic ink. Cheques that have been processed in this way are sent to special
cheque clearing center where they can be processed automatically in very large
batches using magnetic ink character readers. Banks use this method of input
for processing cheques because it is very secure. The equipment needed to
print and read characters in magnetic ink is very expensive and it is unlikely
that anyone would go to the trouble of trying to get hold of some just to forge
cheques.

i) OPTICAL CHARACTER RECOGNITION (OCR):-

Optical Character Recognition or OCR is the use of an ordinary scanner
and special software to convert text in a scanned image into a format that can
be edited by word processing software. Text that is going to be input using OCR
must be printed or written very clearly because poorly shaped or unclear text
won't be recognized. OCR is also used for the reading of typed post codes when
mail is automatically sorted, Payment slips accompanying credit card payments
are also read using OCR. The main difference between OCR and OMR is that
which depends on the shape of the marks whereas OMR depends on the
position of the marks.

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ii) BAR CODES:

A bar code is a set of lines of different thickness that
represent a number. Bar code readers are used to input data from bar
codes. Most products in shops have bar codes on them. Bar code
readers work by shining a beam of light on the lines that makes up the
bar code and detecting that amount of light that is reflected back-Many
bar code readers use the light from a- laser beam to scan the bar code
but others, such as light pens, use an ordinary beam of light. Bar codes
don't store any information about a product such as its price, size and
manufacturer on a shop's computer system. It is not only shops those
use bar codes; many libraries now use bar codes on their books and
membership cards.

iii) MAGNETIC STRIPE READERS:

A magnetic stripe is just a thin band of magnetic tape similar
to the tape inside a music cassette. The most common place that you'll
come across a magnetic stripe is on the back of a credit or debit card.
Magnetic stripes are also used on identity cards and electronic key
cards in hotels and businesses. Some schools register their students
using identity cards with a magnetic stripe reader. The computer
identifies each student by reading the identity number from the
magnetic stripe on their card. Magnetic stripes can hold only a small
amount of data and are quite easy to forge. In the next few years'
magnetic stripes will be replaced with smart cards which will store
much more data on a small microchip built into the surface of the card.

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3.2 OUTPUT DEVICES:

Output devices are used to display the information or
Output. Before a computer can produce any output it must have an.
output device connected to it. The output devices that you most
probably use will be screen or monitor and the printer. The purpose of
the output devices is to convert data and information expressed in
electronic impulses to human understandable forms. Another sort of
output that you would have experienced when using a computer is
sound, which is output through a speaker.

3.2.1 MONITOR OR VIDEO DISPLAY UNIT(VDU):

(2010" 2009, 2008)

Monitor is commonly used output devices that are used to

display the final result or output. The monitor is also referred to as the

CRT. I.e. Cathode Ray Tube, because actually it is the Cathode Ray Tube.

It is a very popular. Output device as far as the communication with the

computer is concerned. The keyboard and the monitor taken together

is usually referred to as CONSOLE. Console is the term' used .for any

device that establishes the communication between -the computer

user and .the computer. The screen of the monitor is coated from inside

by the Zinc Sulfide. Behind screen there is an electron gun, which bombards

the beam of electrons on the screen from inside. The screen and the

electron gun are designed so that the screen appears to

divided into tiny dots. The size of a monitor is measured in inches

diagonally across screen 15, 17, 19, 21-inch monitors are the most

commonly used.

BASIC TYPES OF MONITOR ACCORDING TO TECHNOLOGY: (2010,2009)
The basic two types monitors are:
Cathode Ray Tube (CRT) Liquid Crystal Display (LCD)

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 CATHODE RAY TUBE (CRT):

The first is the typical monitor that you see on a desktop computer. It is
look like T.V screen and works the same way. This type uses large vacuum tube,
called a CRT. A Computer monitor that uses an electron gun (Cathode) to emit a
beam of electrons that paint the phosphors on the screen as the beam sweeps
across.

 LIQUID CRYSTAL DISPLAY (LCD):

A flat panel monitor on which an image is created when the Liquid
Crystal becomes charged used primarily in notebook and laptop computer
because they are light weight, portable and use little power.

CLASSIFICATIONS OF MONITORS, IN TERMS OF COLOR
CAPABILITIES: (2010)
Monitors can be divided into three main classifications:

1) Monochrome monitors.
2) Gray-scale monitors.
3) Colour monitors.

 MONOCHEROME MONITORS:-

A monochrome monitor can only display two colours, one for the
background and one for the foreground. These colours are normally black and
white, green or amber and black.

 GRAY-SCALE MONITORS:-

A gray-scale monitor is a special type of monochrome monitor that can
display different shades of Grey.

 COLOUR MONITORS:-

A color monitor can display from 16 to 1 million different colors. Color
monitors are sometimes called RGB (Red, Green, Blue) monitors because they
accept three separate digitals - red, green and blue.

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A monitor's quality include the following:

The picture on a monitor is made up of thousands of tiny coloured
dots called pixels. The quality and detail of the picture on a monitor
depends on the, resolution it is capable of displaying. Resolution is
measured in pixels going across and down the screen. A high-resolution
monitor can show much finer detail on the screen than, a low-resolution
monitor because its pictures are made up of a much larger number of
pixels. Resolutions can range from 800x 600 to 1600x 1200 pixels.

Most PCs are supplied with a color 15, 17 inch Super Video Graphics
Array (SVGA) monitor with a resolution of 1024 x 768 pixels. Other
factors that determine a monitor's quality include the following:

FACTORS DETERMINING A MONITOR'S QUALITY:(2010)

(1) Resolution:

A measurement usually expressed in linear Dots Per Inch (dpi),
horizontally and vertically of the sharpness of an image generated by an
output device such as monitor or printer. In monitor, resolution is
expressed as the number of pixels displayed on-screen.

(2) Bandwidth:

A measurement, expressed in Cycles per Second (hertz) or Bits per
Second (BPS) of the amount of information that can flow through a
channel.

(3) Refresh rate:

How many times per second the screen is refreshed. To avoid
flickering the refresh rate should be at least 72Hz.

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(4) Dot Pitch:

The size of the smallest dot that a monitor can display on-screen Dot

pitch determines a monitor's maximum resolution.

(5) Convergence:

The clarity and sharpness of each pixel.

 Advantage of the Monitors (VDU):

(1) Permits interactive computing, where the computer produces an
immediate response to the user.

(2) The screen may be used as both input and output, e.g. when
selecting items from a menu with a mouse, or modifying a drawing
with a light pen or digitizer /graphics tablet. Information retrieval,
e.g. to check if an item is in stock, will produce an immediate output
on the screen.

(3) The VDU is fast, silent and is usually very clear and attractive
compared with paper.

Disadvantages of the Monitors:

(1) There is no permanent record of the output.
(2) There is some evidence of health risks, such as headaches and

eyestrain.

Softcopy:

Softcopy is data that is shown on a display screen or is in audio or voice

form this kind of output is not tenable, it cannot be touched.

3.2.2 PRINTERS:(2014, 2012, 2011)
A printer is an output device that produces a printout or a hard copy of

the output from a computer. There are many different types of printers

available and which one you choose will depend on how much you want to pay

for the printer, the cost of the paper and ink that it uses, what quality of print

you want and whether you are going to print just text, graphics, or graphics and

text - together. The most common types of printer are dot matrix, inkjet and

laser.

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 TYPES OF PRINTERS:(2014, 2012)

Printer can be divided into two main categories IMPACT and NON-

IMPACT. An impact printer produces images by striking the paper. Dot matrix

printers are impact printers. A non-impact pr inter does not strike the paper

when it is printing. Inkjet and laser printers are non-impact printers.

 IMPACT PRINTERS :{ 2011, 2009}

Impact printers are also known as noisy printers. It is term applied to
any printer where the standard typewriter action is used. This means that
these printers print by striking the ribbon against the paper. Impact printers are
also known as noisy printers because they produce much noise during the
printing.

 TYPES OF IMPACT PRINTERS:- (2009)

some of the commonly used impact printers are:

(a) Doc matrix printer (b) Daisy Wheel Printer (c) Line Printer

(a) DOT MATRIX PRINTER:

A dot matrix printer prints characters and graphics on the paper by
producing patterns of dots. if you look closely at a printout from a dot matrix
printer you will see the tiny dots, which make up the printout. Dot matrix
printers can print up to 500 CPS. Dot matrix printers, are limited to one or a
few founts. Dot matrix printers are relatively cheap and so is the stationery
that they use. Because they are impact printers with the dots being printed by
pins striking a ribbon against the paper, it is possible to print 2 or 3 copies. The
quality of dot matrix printouts depends upon how many pins there are in the
print head. "9 pin" printer will produce much poorer quality printouts than a
"24-pin" printer. Dot matrix printers can be quite noisy and often need a
special acoustic cover to reduce the amount of sound that they produce.

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 Advantages of Dot Matrix Printers:

 Relatively high speed (typically 200 characters per second, but more
expensive dot- matrix printers approach 500 cps in draft mode).

 Pictures (graphics) may be printed using a screen dump program.
 Relatively cheap.

 Disadvantages:

• Quality not acceptable for some purposes (e.g. legal documents,
publishing, and business correspondence).

(b) DAISYWHEEL PRINTER:

The daisy wheel printer employs exactly the same design of printing
mechanism as the electronic typewriter. The daisywheel consists of a complete
set of characters attached to spokes around a central hub. As the daisywheel is
moved across the paper, it is continually rotated to bring the required letters
into position. A complete character is printed on the paper by striking the
appropriate petal onto an inked ribbon. Daisy wheel printers can print only
text. The daisywheel printer is frequently used with a microcomputer for word-
processing, as an alternative to the typewriter.

 Advantage of the Daisywheel Printers:

The main advantage of the daisywheel is that perfectly typed letters
may be produced.

Disadvantages of the Daisywheel Printers:

1. The daisywheel printer is very slow (8-100 cps)
2. Printing is very noisy and acoustic hoods are sometimes needed for

sound proofing in an office environment.
3. Daisywheel printers are the least versatile of all printers fonts can only

be changed by fitting a different daisywheel, e.g. a single word cannot
he highlighted in italics the middle of a sentence.
4. Graphics or pictures are not possible.

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(1) LINE PRINTER:

Line printer prints one complete line of output at a time. These printers
are almost universally of the fully formed character, (Text) impact type. They
are high-speed, high by fitting a different daisywheel, e.g. a single word cannot
he highlighted in italics in capacity devices, with output speed of between 200
and 3000 lines printer.

(2) NON-IMPACT PRINTERS:(2011, 2009)

Non-impact printers are much faster than the impact printer an produce
high quality characters. These printers produce the output result on the paper
without striking the paper because these printers print on paper without
striking. Therefore they produce very low noise and these are also known as
quiet printers.

TYPES OF NON IMPACT PRINTERS: (2009)

These printers fall primarily in the following categories.
 Thermal Printers
 Ink Jet Printers.
 Laser Printer.

 THERMAL PRINTERS:

The thermal printers use heat-sensitive paper to produce the characters
from a pattern of dots. A stylus is used instead of pins as in the dot matrix, and
this bums away the top of the paper to form the letters. The thermal printer is
slow (about 30 characters per second.)

 INK-]ET PRINTERS:

Ink-jet printers are similar to Dot-Matrix printers, but instead of small
needles being, forced against a ribbon, ink is sprayed out of tiny nozzles to
form characters from a series of spots. Since there is no impact the ink jet
printer is fast and quite. A main feature is that text and graphics can be
produced in many different colors. Ink-Jet printers are capable of printing an
almost unlimited variety of fonts.

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 LASER PRINTER:

Laser printers give very high-quality printed output of both text and
graphics very quickly and quietly. Most laser printers will produce between 4
and 20 pages per minute. Laser printers are generally more expensive to buy
than inkjet printers and the toner cartridges are more expensive, but they are
very suitable for large. Volume printouts because of their speed. Color laser
printers are however extremely expensive. Laser printers are capable of
printing an almost unlimited variety of fonts.

 LCD and LED:

Similar to a laser printer, but uses liquid crystals or light emitting diodes
rather than a laser to produce an image on a drum.

3.2.3 PLOTTERS:(2008)

A plotter is another type of output device, which will produce a hard
copy of the output from a computer. The main difference between a plotter
and a printer is that a plotter uses a pen to draw the computer output onto the
paper. Some plotters use a set of colored pens to produce color output.
Plotters produce very accurate drawings and are often used in Computer
Aided Design or CAD.

TYPES OF PLOTTERS:

Plotters can be of two types:

1. Pen Plotters.
2. Electrostatic Plotters.

PEN PLOTTERS:

Pen plotters have an ink pen attached to draw the image. There are two
types of pen plotters.

i) Flatbed Plotter:

This is the most common and is a fixed, flat table or bed on which the
writing pen can move over the paper, up (to move without drawing), down (to
draw) and in North, South, West, East, directions.

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ii) Drum Plotter:

Here a roll of paper, mounted on a drum, can be moved back and forth
whilst the pen moves across the paper. A combination of drum and pen
movements allows a line to be drawn anywhere on the paper.

ELECTROSTATIC PLOTTER:

This, type of plotter produces a faster image by changing the paper
with high voltage. This voltage attracts toner, which is then melted on to the
paper with heat. This type of plotter is fast, but the quality is generally
considered to be-poor when compared to pen plotters.

DIFFERENCES BETWEEN PRINTERS AND PLOTTERS

PRINTERS PLOTTERS

1 ) Printers do not use a pen to draw 1) Plotters draw lines using a pen.
lines.

2) They are smaller in size as 2) They are bigger in size as compared
compared to plotters. to printers.

3) They are inexpensive in cost. 3) They are expensive in cost.

4) They are fast in speed. 4) They are slow in speed.

DIFFERENCE BETWEEN INPUT DEVICES AND OUTPUT DEVICES

INPUT DEVICES OUTPUT DEVICES

1) The most commonly used or 1) The most commonly used or
primary input device is Keyboard. primary output device is monitor.

2) The devices that are used to feed 2) The devices that are used to display
data Into the computer are called the, result to the order world of the
input devices. computer are called output devices.

3) A variety of input device are used 3) A variety of output devices are
with the computer. Depending on the used with computer. Depending on
type and purpose input information. the type and purpose of output.

4) They have two modes of input. 4) They have two modes of output.
i) Manual input mode (Keyboard) i) Soft copy output (monitor)
ii) Direct input mode (OMR, RCR) ii) Hard copy output (printer)

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3.3 DUAL PURPOSE DEVICES (INPUT IOUTPUT DEVICES) (2012)

Dual purpose devices are devices that are used as input and output
devices at the same time e.g. Disk Drive and CD- Writer.

3.3.1 DISK DRIVE:

Disk drive is a peripheral device that reads or writes the disks (hard disks,
floppy disks, etc.) that store information. Disk drives are called "storage
devices" because they store information on portable or permanent disks. The
drive contains a motor to rotate the disk at a constant rate and one or more!
Write heads, which are positioned over the, desired track. When the disk drive
is used to read some data from the disk, it will fall in the category of input
devices; while during writing data onto, the disk it will be considered as an
output device.

3.3.2 CD WRITER:

A CD writer a device connected to your computer which can write on
CD-RW and CD-R discs. CD-RW discs may be written, erased and rewritten,
while CD-R discs may be written only once. CD writer performance is
measured in "X" units, where 1 X = 150 kilobytes/second. This allows users to
"master" a CD-ROM or audio CD for publishing. CD-R drives-can also read CD-
ROMS and plays audio CDs.

The CD writer is also called a CD-R drive (Compact Disk-Recordable drive

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3.4 EXERCISE:

Q No. 1 what do you mean by pointing input devices? Write some
examples of such devices.
The pointing device corresponding movement being
communicated to the computer to control cursor position on
screen. It enables computers to be used by none expects in a
"user-friendly" fashion. It cannot be used for entering numeric
or text data.
The most common pointing input devices are:
1) Mouse 2) Track Ball 3) Joystick 4) Light Pen

Q No.2 what is the difference between Hardcopy and Softcopy?

DIFFERENCE BETWEEN HARDCOPY AND SOFTCOPY

SOFT COPY HARD COPY

1) Output on screen is called a soft copy 1) Output on paper is called a hard copy.

2) It is a temporary form of output. 2) It is a permanent form of output.

3) Soft copy is fixed. 3) Hard copy is moveable.

4) It cannot be touchable. 4) It can be touchable

5) It cannot be moveable. S) It can be moveable.

Q No.3 what is the use of Cursor Movement keys in a keyboard?

Ans. Cursor Movement Keys that move the on-screen cursor. With
most programs the arrow keys on the numeric keypad move the
cursor in the directions of the arrows. You can move the cursor one
character left or right or one line up or down. Like the keys in the
typing area, these keys are auto repeat keys. If you hold down the
key, the cursor keeps moving in the direction indicated. The newest
keyboards often include a separate cursor keypad with keys
that perform the same function as the arrows keys on the numeric
keypad. These keys include HOME, END, PAGE UP and PAGE DOWN

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Q No.4 What is the Major difference between Mouse and Track Ball?

 MOUSE:

We do not use a mouse by rolling the ball with our palm or
finger, we use a flat surface. It requires much space to use it.

TRACK Ball:-

We use a trackball by rolling the ball with our palm or finger. It
does not require much space to use it.

Q No.5 Define different types of Scanners?

 TYPES OF SCANNERS:

Depending on the volume and type of material to be scanned,

you can use Flatbed scanner, Sheet-fed scanner and even small

Hand-held scanners.

(i) Flatbed Scanners:

They are most versatile and commonly used scanners. They are the
stationary scanners that hold the data (image documents) in place while the
scanning mechanism passed over it. This type of scanner has a flat piece of
glass. A flatbed scanner like a photocopying machine.

(ii) Sheet-fed scanners:

A sheet-fed scanner looks like a small portable printer. A scanner that
feed each sheer of paper across a nonmoving scan head; this is different from
the flatbed scanner in which the paper is laid on a sheet of glass and the scan
head moves. This scanner cannot be used to scan pages, books or magazines.

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