FIT Unit 1 Chapter 1 and 3.pdf huii hjjji uuu
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About This Presentation
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Slide Content
Fundamentals of Information Technology Unit -1
Geetha Poornima K
Assistant Professor
Dept of Computer Science
St Philomena College Puttur
Geetha Poornima K
Assistant Professor
Dept of Computer Science
St Philomena College Puttur
Data Processing
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Data coded in
computer
understandable
form
Input via input device
Information
stored and
retrieved from
secondary
storage
Output via output device
Processed
data to the
output device
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Data coded in
computer
understandable
form
Input via input device
Information
stored and
retrieved from
secondary
storage
Output via output device
Processed
data to the
output device
Importance of Input/Output Devices
Steps in data processing
Step 1: Data input via an input device
Step 2: Processing of Data
Step 3: Data output via an output device
Input device is important as the processing depends on the input
Output also depends on input
When proper input is given we get proper output
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Steps in data processing
Step 1: Data input via an input device
Step 2: Processing of Data
Step 3: Data output via an output device
Input device is important as the processing depends on the input
Output also depends on input
When proper input is given we get proper output
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Input Devices
Two types
Manual: Data is entered toa computer using hands. Example Keyboard,
Mouse
Direct: Data is sent automatically from a source to the computer. Example
MICR
Some commonly used input devices: Keyboard, mouse, joystick, digital
camera, scanner, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Two types
Manual: Data is entered toa computer using hands. Example Keyboard,
Mouse
Direct: Data is sent automatically from a source to the computer. Example
MICR
Some commonly used input devices: Keyboard, mouse, joystick, digital
camera, scanner, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Keyboard
Used to input text and commands
Resembles regular typewriter with a few additional keys. Most
commonly used type of keyboard is QWERTY.
AZERTY, DVORAK are some other types of keyboards
Number of keys varies form 84 to 104 depending on manufacturers
It is the easiest input device that does not need any special skills
Data entry is slow as user may have to manually type all text
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Used to input text and commands
Resembles regular typewriter with a few additional keys. Most
commonly used type of keyboard is QWERTY.
AZERTY, DVORAK are some other types of keyboards
Number of keys varies form 84 to 104 depending on manufacturers
It is the easiest input device that does not need any special skills
Data entry is slow as user may have to manually type all text
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Pointing Devices
In some applications keyboard is not sufficient.
For example, if the user wants to select an item from a list, the user can
identify that item's position by selecting it through the keyboard.
However, this action could be performed quickly by pointing at the
correct position.
A pointing device is used to communicate with the computer by
pointing to locations on the monitor screen.
Such devices do not require keying of characters; instead the user can
move a cursor on the screen and perform move, click, or drag
operations.
Example: Mouse, Trackball, Joystick, Light pen, Touch screen and
Trackpad.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
In some applications keyboard is not sufficient.
For example, if the user wants to select an item from a list, the user can
identify that item's position by selecting it through the keyboard.
However, this action could be performed quickly by pointing at the
correct position.
A pointing device is used to communicate with the computer by
pointing to locations on the monitor screen.
Such devices do not require keying of characters; instead the user can
move a cursor on the screen and perform move, click, or drag
operations.
Example: Mouse, Trackball, Joystick, Light pen, Touch screen and
Trackpad.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Mouse
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Mouseis a small hand-held pointing device which can be used to
input commands or information.
•Pointing device that translates the motion of mouse into signals.
•It contains two or three buttons and by pressing one of the buttons,
the mouse either marks a place on the screen or makes selections
from the data on the screen.
•Click, double click, right click, drag and drop are the operations
that can be done using a mouse.
•It may be classified as a mechanicalmouseor an opticalmouse
based on the technology it uses.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Mouseis a small hand-held pointing device which can be used to
input commands or information.
•Pointing device that translates the motion of mouse into signals.
•It contains two or three buttons and by pressing one of the buttons,
the mouse either marks a place on the screen or makes selections
from the data on the screen.
•Click, double click, right click, drag and drop are the operations
that can be done using a mouse.
•It may be classified as a mechanicalmouseor an opticalmouse
based on the technology it uses.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Mouse
Mouse
Mouse
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Mechanical mouse has a rubber ball at the bottom.
•When the user moves the mouse along the flat surface, the ball rolls.
•The distance, speed, direction is tracked.
•Inside the mouse are three rollers.
•One of them, which is mounted at a 45
0
angle to the other two (mounted at 90 degree
to each other), is spring loaded.
•It is there to hold the ball against the other two rollers. When mouse ball rotates, rollers
also rotate.
•The rollers are connected to axels, and the axels are connected to a small sensor that
measures how fast the axel is turning.
•Both sets of information are passed to the electronics inside the mouse.
•This information is passed via mouse cord, where the operating system then moves the
pointer accordingly.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Mechanical mouse has a rubber ball at the bottom.
•When the user moves the mouse along the flat surface, the ball rolls.
•The distance, speed, direction is tracked.
•Inside the mouse are three rollers.
•One of them, which is mounted at a 45
0
angle to the other two (mounted at 90 degree
to each other), is spring loaded.
•It is there to hold the ball against the other two rollers. When mouse ball rotates, rollers
also rotate.
•The rollers are connected to axels, and the axels are connected to a small sensor that
measures how fast the axel is turning.
•Both sets of information are passed to the electronics inside the mouse.
•This information is passed via mouse cord, where the operating system then moves the
pointer accordingly.
Trackball
A pointing device that resembles a nestled ball in a square cradle
It serves as an alternative to mouse
The ball can be rotated easily and based on its rotation, the cursor moves
It comes in various sizes and shapes but its functioning is same.
It is also used same way as that of mouse whereas mouse is moved but trackball is
stationary only the ball is moved not the entire device
Used by gamers and graphic designers
Requires less space than mouse
May contain several buttons.
Not supplied with the computer.
To use them some sort of expertise is needed
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
A pointing device that resembles a nestled ball in a square cradle
It serves as an alternative to mouse
The ball can be rotated easily and based on its rotation, the cursor moves
It comes in various sizes and shapes but its functioning is same.
It is also used same way as that of mouse whereas mouse is moved but trackball is
stationary only the ball is moved not the entire device
Used by gamers and graphic designers
Requires less space than mouse
May contain several buttons.
Not supplied with the computer.
To use them some sort of expertise is needed
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Joystick
It moves in all directions and controls the movement of the cursor
It is a stick attached to a plastic base with a flexible rubber cover
The plastic base contains the circuitry
Movement of the stick from its central position sends signals to the CPU
Comes in three variants: Digital, Glide an Direct.
Digital offers limited movement like up, down, left and right
Glide and direct allow 360
0 movement
Direct has added ability to control velocity of the screen cursor movement
Used by gamers, flight simulators, CAD/CAM and graphic designers
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It moves in all directions and controls the movement of the cursor
It is a stick attached to a plastic base with a flexible rubber cover
The plastic base contains the circuitry
Movement of the stick from its central position sends signals to the CPU
Comes in three variants: Digital, Glide an Direct.
Digital offers limited movement like up, down, left and right
Glide and direct allow 360
0 movement
Direct has added ability to control velocity of the screen cursor movement
Used by gamers, flight simulators, CAD/CAM and graphic designers
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Light Pen
Also called as mouse pen
It is a hand-held electro-optical pointing device
Facilitates drawing images on the screen
It does not emit light but its photo sensitive diode senses the light from the screen
Can be used the same way as that of a mouse
Users can interact more easily
Allows users to make menu selections, draw and perform other input operations
Perfect where desk space is limited
Useful to identify specific location on the screen
Does not recognize anything when kept at blank portion of the screen
Affordable and need no maintenance
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Also called as mouse pen
It is a hand-held electro-optical pointing device
Facilitates drawing images on the screen
It does not emit light but its photo sensitive diode senses the light from the screen
Can be used the same way as that of a mouse
Users can interact more easily
Allows users to make menu selections, draw and perform other input operations
Perfect where desk space is limited
Useful to identify specific location on the screen
Does not recognize anything when kept at blank portion of the screen
Affordable and need no maintenance
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Touch Screen
A special kind of input device that allows direct
selection with the touch of finger
Needed when information is to be accessed with
minimum effort
Not suitable for input of a large amount of data
Used in hospitals, supermarkets, railway reservation
counters, airlines, amusement parks, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
A special kind of input device that allows direct
selection with the touch of finger
Needed when information is to be accessed with
minimum effort
Not suitable for input of a large amount of data
Used in hospitals, supermarkets, railway reservation
counters, airlines, amusement parks, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Trackpad
It is also called as touchpad
It is a stationary pointing device that works by sensing the movement of finger
across a small sensitive surface
Small in size (1.5 to 2 inches)
Is generally used in laptops
Sometimes attached to Personal Digital Assistants (PDAs) such as iPod.
Consist of 2-3 buttons that work same as that of mouse
Many trackpads are strike-sensitive. Users can tap on trackpad to maximize and
minimize window, selecting an object, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It is also called as touchpad
It is a stationary pointing device that works by sensing the movement of finger
across a small sensitive surface
Small in size (1.5 to 2 inches)
Is generally used in laptops
Sometimes attached to Personal Digital Assistants (PDAs) such as iPod.
Consist of 2-3 buttons that work same as that of mouse
Many trackpads are strike-sensitive. Users can tap on trackpad to maximize and
minimize window, selecting an object, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Speech Recognition
It is the most interactive way to communicate with the computer
Requires a microphone and speech recognition software
This technology converts words, phrases spoken by humans to digital signals which are
transformed into signals
They are speaker dependent. They are to be trained for each user
If the computer performs speech recognition, no need to type the documents
Speech recognition systems are used to create documents such as e-mails, text
documents, etc.
The speech recognition system allows user to interact directly without the need of mouse
and keyboard
The computer should have microphone, speech recognition software and Sound card
The reliability of a speech recognizer is lesser
It is not suitable for noisy places
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It is the most interactive way to communicate with the computer
Requires a microphone and speech recognition software
This technology converts words, phrases spoken by humans to digital signals which are
transformed into signals
They are speaker dependent. They are to be trained for each user
If the computer performs speech recognition, no need to type the documents
Speech recognition systems are used to create documents such as e-mails, text
documents, etc.
The speech recognition system allows user to interact directly without the need of mouse
and keyboard
The computer should have microphone, speech recognition software and Sound card
The reliability of a speech recognizer is lesser
It is not suitable for noisy places
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Digital Camera
Stores images in digital format
The images can be transferred into a computer and processed using
sophisticated software
They can also be printed using a printer
Photos are inexpensive, easy to process as there is no processing of film
Images can be viewed on a large-screen TV
Image data can be immediately used on a PC, without processing.
Editing is easy using a photo editing software
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Stores images in digital format
The images can be transferred into a computer and processed using
sophisticated software
They can also be printed using a printer
Photos are inexpensive, easy to process as there is no processing of film
Images can be viewed on a large-screen TV
Image data can be immediately used on a PC, without processing.
Editing is easy using a photo editing software
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Webcam
It is another name for web camera
It is a portable video camera that captures live videos
Most laptops contain a webcam or it can be connected through a USB port
Two types
Streaming : Captures moving images (30 images per second)
Snapshot : Captures only still images (Once every 30 seconds)
Extensively used in video conferencing, live chats, etc.
Used by educational institutions to conduct distance classes
It is easy to install and use
Affordable. If it has additional features like auto focus, face tracking, etc., its cost may
increase
It can produce only real images. Hence it cannot be used unless attached with a PC.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It is another name for web camera
It is a portable video camera that captures live videos
Most laptops contain a webcam or it can be connected through a USB port
Two types
Streaming : Captures moving images (30 images per second)
Snapshot : Captures only still images (Once every 30 seconds)
Extensively used in video conferencing, live chats, etc.
Used by educational institutions to conduct distance classes
It is easy to install and use
Affordable. If it has additional features like auto focus, face tracking, etc., its cost may
increase
It can produce only real images. Hence it cannot be used unless attached with a PC.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Webcam Vs Digital Camera
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Webcam Digital Camera
Does not contain any built-in memoryContains a memory card to store the
images and videos
Captures images and sends them to the
network immediately
Stores the images in its memory card
Designed to capture low-resolution
images
Designed to capture high-quality images
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Webcam Digital Camera
Does not contain any built-in memoryContains a memory card to store the
images and videos
Captures images and sends them to the
network immediately
Stores the images in its memory card
Designed to capture low-resolution
images
Designed to capture high-quality images
Microphone
It is an input device to input sound that is then stored in a digital form
IT is used for applications such as adding sound to a multimedia
presentation or for mixing music
It is used in recordingaudiofor a video, Voice recognition, Computer
gaming, Online chatting, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It is an input device to input sound that is then stored in a digital form
IT is used for applications such as adding sound to a multimedia
presentation or for mixing music
It is used in recordingaudiofor a video, Voice recognition, Computer
gaming, Online chatting, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Scanners
A scanner is an input device that converts a document into
electronic format that can be stored on the disk.
Electronic image can be edited, stored and combined and printed
easily
They are called optical scanners as light beam is used to scan the
input
Scanners come with a software that allows the scanned images to be
communicated to computer
They can store images in both greyscale and color mode.
Two types
Hand-held scanners
Flatbed scanners
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
A scanner is an input device that converts a document into
electronic format that can be stored on the disk.
Electronic image can be edited, stored and combined and printed
easily
They are called optical scanners as light beam is used to scan the
input
Scanners come with a software that allows the scanned images to be
communicated to computer
They can store images in both greyscale and color mode.
Two types
Hand-held scanners
Flatbed scanners
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Hand-held Scanners
It contains LEDs which are placed over documents to be scanned
It is small in size
Available either in color or in grayscale mode
Scanning is done slowly from top to bottom
The document scanned will be converted into image
When scanning, the scanner is dragged over the document slowly
and steadily
Resolution is 800 dpi
Used to read data in price tags, shipping labels and ISBNs on books
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It contains LEDs which are placed over documents to be scanned
It is small in size
Available either in color or in grayscale mode
Scanning is done slowly from top to bottom
The document scanned will be converted into image
When scanning, the scanner is dragged over the document slowly
and steadily
Resolution is 800 dpi
Used to read data in price tags, shipping labels and ISBNs on books
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Working of Hand-held Scanners
When the scan button of handheld scanner is pressed, an LED illuminates.
The inverted angled mirror on the scanner reflects the image onto the lens of the
scanner located at the back
Lens focuses a single line of image into a charged coupled device (CCD)
CCD contains a row of light detectors
When light shines on these detectors they record the amount of light as voltage
Voltages are sent to analog chip which corrects color detection errors if any
The single line of image is then sent to an analog to digital converter (ADC)
which converts analog signals into binary format
Then it is sent to the computer
Converter clears itself to accept the next line and so on.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
When the scan button of handheld scanner is pressed, an LED illuminates.
The inverted angled mirror on the scanner reflects the image onto the lens of the
scanner located at the back
Lens focuses a single line of image into a charged coupled device (CCD)
CCD contains a row of light detectors
When light shines on these detectors they record the amount of light as voltage
Voltages are sent to analog chip which corrects color detection errors if any
The single line of image is then sent to an analog to digital converter (ADC)
which converts analog signals into binary format
Then it is sent to the computer
Converter clears itself to accept the next line and so on.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Flatbed Scanners
It looks similar to a photocopier machine.
It consists of a box containing a glass plate on its top and a lid that covers the
glass plate.
The glass plate is used for placing the document to be scanned.
The light beam is placed below the glass plate and when it is activated,it
moves horizontally from left to right.
After scanning one line, the light beam moves in order to scan the next line
and the procedure is repeated until all the lines are scanned.
Scanning an A4 size document takes about 20 seconds.
They can scan black and white as well as color images.
They are larger in size and more expensive than hand-held scanners.
Produce better quality images because they employ better scanning
technology
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It looks similar to a photocopier machine.
It consists of a box containing a glass plate on its top and a lid that covers the
glass plate.
The glass plate is used for placing the document to be scanned.
The light beam is placed below the glass plate and when it is activated,it
moves horizontally from left to right.
After scanning one line, the light beam moves in order to scan the next line
and the procedure is repeated until all the lines are scanned.
Scanning an A4 size document takes about 20 seconds.
They can scan black and white as well as color images.
They are larger in size and more expensive than hand-held scanners.
Produce better quality images because they employ better scanning
technology
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Working of a Flatbed Scanner
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•To scan a document, it is placed on the glass plate and the cover is closed.
•A lamp is used to illuminate the document. The scan head (mirrors, lens, filter and
CCD array constitutes a scan head) is moved slowly across the document by a belt
that is attached to a stepper motor.
•The head is attached to a stabilizer bar to ensure that there is no wobble or
deviation in the pass.
•In scanning terms, a pass means that the scan head has completed a single complete
scan of the document.
•The image of the document is reflected by an angled mirror to another mirror.
•Each mirror is slightly curved to focus the image it reflects onto a smaller surface.
•The last mirror reflects the image onto a lens. The lens focuses the image through a
filter on the CCD array.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•To scan a document, it is placed on the glass plate and the cover is closed.
•A lamp is used to illuminate the document. The scan head (mirrors, lens, filter and
CCD array constitutes a scan head) is moved slowly across the document by a belt
that is attached to a stepper motor.
•The head is attached to a stabilizer bar to ensure that there is no wobble or
deviation in the pass.
•In scanning terms, a pass means that the scan head has completed a single complete
scan of the document.
•The image of the document is reflected by an angled mirror to another mirror.
•Each mirror is slightly curved to focus the image it reflects onto a smaller surface.
•The last mirror reflects the image onto a lens. The lens focuses the image through a
filter on the CCD array.
Optical Character Recognition
All OCR systems include a scanner for reading text
and sophisticated software for converting the text into
machine-readable form.
During OCR processing, the text is analyzed for light
and dark areas in order to identify each alphabetic
letter or numeric digit.
When a character is recognized, it is converted into an
ASCII code.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
All OCR systems include a scanner for reading text
and sophisticated software for converting the text into
machine-readable form.
During OCR processing, the text is analyzed for light
and dark areas in order to identify each alphabetic
letter or numeric digit.
When a character is recognized, it is converted into an
ASCII code.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Magnetic Inc Character Recognition (MICR)
MICR gives extra security against forgeries such as color copies of
payroll cheques or hand-altered characters on a cheque
If a document has been forged, say using a color print, the magnetic ink
line will either not respond to magnetic fields, or will produce an
incorrect code when scanned using a device designed to recover the
information in the magnetic characters.
Only a limited number of digits and character are available for encoding.
Reading speed of MICR is higher.
It is very efficient and time-saving
Avoids errors in banks
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
MICR gives extra security against forgeries such as color copies of
payroll cheques or hand-altered characters on a cheque
If a document has been forged, say using a color print, the magnetic ink
line will either not respond to magnetic fields, or will produce an
incorrect code when scanned using a device designed to recover the
information in the magnetic characters.
Only a limited number of digits and character are available for encoding.
Reading speed of MICR is higher.
It is very efficient and time-saving
Avoids errors in banks
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Barcode Reader
Barcode is a machine readable pattern of parallel vertical lines of
varying width
It is used for labelling goods in supermarkets
The device that senses the barcode is called barcode reader
The information read using a barcode reader is fed to the computer
that recognizes the information
There are two types of barcode readers
Hand-held : Used to read barcodes on stationary items
Fixed-mount scanners : Items having barcode are passed using a
conveyer belt in industries (Automatic inventory updating)
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Barcode is a machine readable pattern of parallel vertical lines of
varying width
It is used for labelling goods in supermarkets
The device that senses the barcode is called barcode reader
The information read using a barcode reader is fed to the computer
that recognizes the information
There are two types of barcode readers
Hand-held : Used to read barcodes on stationary items
Fixed-mount scanners : Items having barcode are passed using a
conveyer belt in industries (Automatic inventory updating)
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Barcode Reader
A barcode scanner can record five to seven times faster than a typist
It is accurate. Error rate is 1 in 3 millions
Reduces labour
Reduces data collection errors
Widely used in supermarkets, libraries and departmental stores
Barcode scanners are electro-optical devices
Light wave is converted from analog to digital forma and sent to a computer
The device contains a sensor that detects light reflected by the barcode and
converts light to electrical energy
The electrical signal is converted into alpha numeric format
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
A barcode scanner can record five to seven times faster than a typist
It is accurate. Error rate is 1 in 3 millions
Reduces labour
Reduces data collection errors
Widely used in supermarkets, libraries and departmental stores
Barcode scanners are electro-optical devices
Light wave is converted from analog to digital forma and sent to a computer
The device contains a sensor that detects light reflected by the barcode and
converts light to electrical energy
The electrical signal is converted into alpha numeric format
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Output Devices
Output is the data which is converted into information
It can be displayed on the monitor, printed on a printer or
listened using a speaker
There are two forms of output
Which is readily understood by humans
Which is stored on secondary storage devices for further
processing
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Output is the data which is converted into information
It can be displayed on the monitor, printed on a printer or
listened using a speaker
There are two forms of output
Which is readily understood by humans
Which is stored on secondary storage devices for further
processing
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Types of Output Devices
Hard copy
Soft copy
The physical form of output is known as hard copy.
It refers to the recorded information copied from a
computer onto paper or some other durable surface such as microfilm.
It is permanent and relatively stable form of output
This type of output is highly portable.
Paper is the most extensively used hard-copy medium
Examples for Hard copy: Printed documents, reports, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Hard copy
Soft copy
The physical form of output is known as hard copy.
It refers to the recorded information copied from a
computer onto paper or some other durable surface such as microfilm.
It is permanent and relatively stable form of output
This type of output is highly portable.
Paper is the most extensively used hard-copy medium
Examples for Hard copy: Printed documents, reports, etc.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Soft copy
The electronic version of an output, which usually resides in
computer memory and/or on disk, is known as soft copy.
Soft copy is not permanent.
It is transient and is usually displayed on the screen.
This kind of output is not tangible, that is, it cannot be touched.
Soft copy of outputs include digital form of reports,
presentations, audio and visual forms of outputs
Text or graphics displayed on a monitor also comes under this
category
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
The electronic version of an output, which usually resides in
computer memory and/or on disk, is known as soft copy.
Soft copy is not permanent.
It is transient and is usually displayed on the screen.
This kind of output is not tangible, that is, it cannot be touched.
Soft copy of outputs include digital form of reports,
presentations, audio and visual forms of outputs
Text or graphics displayed on a monitor also comes under this
category
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Examples
Hard copy devices:
Printers, plotters, microfilms
Soft copy devices
Monitors, Voice response systems, LCD
projectors, headsets, electronic
whiteboards, headphones
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Hard copy devices:
Printers, plotters, microfilms
Soft copy devices
Monitors, Voice response systems, LCD
projectors, headsets, electronic
whiteboards, headphones
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Printers
It produces the output from the computer on the paper.
It produces a hard copy i.e. permanent copy of the result which can be stored and
read later.
It prints 80 or 132 columns of characters in each line, and prints either on single
sheets or on a continuous roll of paper.
The quality of a printer is determined by its resolution.
For printers, the resolution is measured in dpi(dots per inch).
The more the dpi, the better will be the quality of image.
If a printer has 600 dpi resolution then it is capable of printing 360,000 dots per
square inch
The speed of early printers was measured in units of characters perminute(cpm)
for character printers, or lines perminute(lpm) for line printers. Modern printers
are measured in pages perminute(ppm)
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It produces the output from the computer on the paper.
It produces a hard copy i.e. permanent copy of the result which can be stored and
read later.
It prints 80 or 132 columns of characters in each line, and prints either on single
sheets or on a continuous roll of paper.
The quality of a printer is determined by its resolution.
For printers, the resolution is measured in dpi(dots per inch).
The more the dpi, the better will be the quality of image.
If a printer has 600 dpi resolution then it is capable of printing 360,000 dots per
square inch
The speed of early printers was measured in units of characters perminute(cpm)
for character printers, or lines perminute(lpm) for line printers. Modern printers
are measured in pages perminute(ppm)
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Types of printers
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Impact Printers
They work by physically striking a head or needle against an ink
ribbon to make on the paper.
They areprinterswhich works by creating a direct contact between
ink ribbon and paper.
They are noisy yet popular.
Impact printershave mechanical moving parts to conductprinting.
Example: Dot matrix printers, daisy wheel printers and drum
printers.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
They work by physically striking a head or needle against an ink
ribbon to make on the paper.
They areprinterswhich works by creating a direct contact between
ink ribbon and paper.
They are noisy yet popular.
Impact printershave mechanical moving parts to conductprinting.
Example: Dot matrix printers, daisy wheel printers and drum
printers.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Non-impact Printers
They use techniques other than physically striking the page to transfer ink onto the
page.
Example: Ink-jet Laser printers
They form characters and images without direct physical contact between the printing
mechanism and the paper.
For example, inkjet printers spray tiny drops of ink onto the page
Laser printers have a cylindrical drum that rolls electrically charged ink onto the
paper.
Non-impact printers use a cartridge filled with toner or liquid ink, which allows them
to produce fine-quality images.
When compared to dot-matrix printers, they are faster and quieter
They produce more clear output than dot-matrix printers.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
They use techniques other than physically striking the page to transfer ink onto the
page.
Example: Ink-jet Laser printers
They form characters and images without direct physical contact between the printing
mechanism and the paper.
For example, inkjet printers spray tiny drops of ink onto the page
Laser printers have a cylindrical drum that rolls electrically charged ink onto the
paper.
Non-impact printers use a cartridge filled with toner or liquid ink, which allows them
to produce fine-quality images.
When compared to dot-matrix printers, they are faster and quieter
They produce more clear output than dot-matrix printers.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
DOT MATRIX PRINTER
Also called wired matrix printers
Prints each characters and images as a pattern of dots.
Prints one character at a time.
Relatively low in cost.
Allows to print characters (any) of any font, and graphics(charts and graphs).
Speed is measured in character per second (cps).
Its speed is from 200 to over 500cps.
Print quality is determined by the number of pins which can vary from 9 to 24.
More pins per inch implies more resolution. More resolution implies more
clarity
Most of them have a resolution ranging from 72 to 360dpi.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Also called wired matrix printers
Prints each characters and images as a pattern of dots.
Prints one character at a time.
Relatively low in cost.
Allows to print characters (any) of any font, and graphics(charts and graphs).
Speed is measured in character per second (cps).
Its speed is from 200 to over 500cps.
Print quality is determined by the number of pins which can vary from 9 to 24.
More pins per inch implies more resolution. More resolution implies more
clarity
Most of them have a resolution ranging from 72 to 360dpi.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
DOT MATRIX PRINTER
They are inexpensive and low operating costs.
Printers are able to use different fonts, different line densities
and different types of paper.
They can print characters either from right or left (hence they
are bidirectional)
Print only in blue/ black color
They can not print graphic objects adequately.
We can take carbon copies of a print.
Here quality is not too important
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
They are inexpensive and low operating costs.
Printers are able to use different fonts, different line densities
and different types of paper.
They can print characters either from right or left (hence they
are bidirectional)
Print only in blue/ black color
They can not print graphic objects adequately.
We can take carbon copies of a print.
Here quality is not too important
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
WORKIMG OF DOT MATRIX PRINTER
The paper is pressed against a rubber-coated cylinder
and is pulled forward as printing progress.
Printer consists of an electro-magnetically driven print
head, which is made up of numerous print wires (pins).
The characters are formed by moving the electro-
magnetically driven print head across the paper, which
strikes the printer ribbon situated between the paper
and print head pin.
As the head stamps onto the paper through the inked
ribbon, a character is produced that is made up of these
dots.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
The paper is pressed against a rubber-coated cylinder
and is pulled forward as printing progress.
Printer consists of an electro-magnetically driven print
head, which is made up of numerous print wires (pins).
The characters are formed by moving the electro-
magnetically driven print head across the paper, which
strikes the printer ribbon situated between the paper
and print head pin.
As the head stamps onto the paper through the inked
ribbon, a character is produced that is made up of these
dots.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
DOT MATRIX PRINTER
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Dot Matrix Printer
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Dot Matrix Printer
ADVANTAGES AND DISADVANTAGES
•1) Can print on multi-part forms or carbon copies.
•2) Lowprintingcost per page.
•3) Can be used on continuous form paper, useful for data logging.
•4) Reliable, durable.
•1) Noisy.
•2) Limited print quality.
•3) Lowprintingspeed.
•4) Limited colorprinting.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•1) Can print on multi-part forms or carbon copies.
•2) Lowprintingcost per page.
•3) Can be used on continuous form paper, useful for data logging.
•4) Reliable, durable.
•1) Noisy.
•2) Limited print quality.
•3) Lowprintingspeed.
•4) Limited colorprinting.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
DAISY WHEEL PRINTERS
A daisy wheel printer is a specific type of mechanical
impact printer popular in the 1970s
It used individual letter, number and symbol keys to
imprint text on paper.
This innovation on the electric typewriter became
popular for its speed and quality, but later fell out of
fashion in the 1990s.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
A daisy wheel printer is a specific type of mechanical
impact printer popular in the 1970s
It used individual letter, number and symbol keys to
imprint text on paper.
This innovation on the electric typewriter became
popular for its speed and quality, but later fell out of
fashion in the 1990s.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Inkjet Printer
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Most common printer used in small business and home today.
•That places extremely small droplets of ink onto paper to create
an image.
•It does not touch paper while creating an image.
•It uses a series of nozzles to spray drops of ink directly onto the
paper.
•Originally they were monochrome. But now nozzles increased to
accommodate C(cyan),M(magenta),Y(yellow),K(black).
•They produce high quality graphics and text patterns.
•These are costlier than dot matrix printers, but quality is better.
•They print with a resolution of 600 dpi or more.
•Can print about 6 pages a minute.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Most common printer used in small business and home today.
•That places extremely small droplets of ink onto paper to create
an image.
•It does not touch paper while creating an image.
•It uses a series of nozzles to spray drops of ink directly onto the
paper.
•Originally they were monochrome. But now nozzles increased to
accommodate C(cyan),M(magenta),Y(yellow),K(black).
•They produce high quality graphics and text patterns.
•These are costlier than dot matrix printers, but quality is better.
•They print with a resolution of 600 dpi or more.
•Can print about 6 pages a minute.
Inkjet Printer
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•An ink-jet printer sprays extremely small droplets of ink onto the
paper to create a character or an image.
•It has a print cartridge with a small series of electrically heated
chambers.
•These chambers are attached to the print head with a series of small
nozzles that spray ink onto the surface of the paper.
•As the print head moves back and forth across the page, the
software gives instructions regarding the type and the quantity of
colours.
•It also tells the position where the dots of ink should be “sprayed”.
Nozzles
Cartridge
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•An ink-jet printer sprays extremely small droplets of ink onto the
paper to create a character or an image.
•It has a print cartridge with a small series of electrically heated
chambers.
•These chambers are attached to the print head with a series of small
nozzles that spray ink onto the surface of the paper.
•As the print head moves back and forth across the page, the
software gives instructions regarding the type and the quantity of
colours.
•It also tells the position where the dots of ink should be “sprayed”.
Nozzles
Cartridge
Disadvantages
Print head is less durable, prone to clogging and
damage.
Expensive replacement ink cartridges.
Not good for high volumeprinting.
Printingspeed is not as fast as laserprinters.
Ink bleeding, ink carried sideways causing blurred
effects on some papers.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Print head is less durable, prone to clogging and
damage.
Expensive replacement ink cartridges.
Not good for high volumeprinting.
Printingspeed is not as fast as laserprinters.
Ink bleeding, ink carried sideways causing blurred
effects on some papers.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Laser Printer
Provides highest quality text and images (with high resolution from
300 to 1200 dpi) for personal computers today.
It is fast printer (4-32 pages text only pages per minute for
microcomputers and up to 200 pages per minute for mainframes).
They are also called page printers because, they process and store
the entire page before they actually print it.
They are more expensive than ink-jet.
They produce sharp, crisp images of both text (with different font
sizes, type styles and sizes) and graphics, providing resolutions from
300 to 2400dpi.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Provides highest quality text and images (with high resolution from
300 to 1200 dpi) for personal computers today.
It is fast printer (4-32 pages text only pages per minute for
microcomputers and up to 200 pages per minute for mainframes).
They are also called page printers because, they process and store
the entire page before they actually print it.
They are more expensive than ink-jet.
They produce sharp, crisp images of both text (with different font
sizes, type styles and sizes) and graphics, providing resolutions from
300 to 2400dpi.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Advantages of Laser Printer
Speed: A laser can move very quickly, so it
can "write" with much greater speed than an
ink jet.
Precision : And because the laser beam has an
unvarying diameter, it can draw more
precisely, without spilling any excess ink.
Economy: suitable for mass printing at low
cost
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Speed: A laser can move very quickly, so it
can "write" with much greater speed than an
ink jet.
Precision : And because the laser beam has an
unvarying diameter, it can draw more
precisely, without spilling any excess ink.
Economy: suitable for mass printing at low
cost
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Disadvantages of Laser Printer
Large high initial investment
Color toner cartridge is expensive
Toner is harmful to humans
Causes environment pollution
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Large high initial investment
Color toner cartridge is expensive
Toner is harmful to humans
Causes environment pollution
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Plotter
It is a pen based output device that is attached to a computer for making
vector graphics using straight lines.
Used to draw high resolution charts, graphs, blueprints, maps, circuit
diagram etc.
Produces lines using pen(are continuous and very accurate) , but printers
produce lines by printing a closely spaced series of dots.
Multicolor plotters use different colored pens to draw different colors
(using CMYK).
Plotter is considered a very slow output device because, it requires
excessive mechanical movement to plot.
It is unable to produce solid fills and shading.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
It is a pen based output device that is attached to a computer for making
vector graphics using straight lines.
Used to draw high resolution charts, graphs, blueprints, maps, circuit
diagram etc.
Produces lines using pen(are continuous and very accurate) , but printers
produce lines by printing a closely spaced series of dots.
Multicolor plotters use different colored pens to draw different colors
(using CMYK).
Plotter is considered a very slow output device because, it requires
excessive mechanical movement to plot.
It is unable to produce solid fills and shading.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Plotter
They are expensive than printers, but can produce more printouts
than standard printers.
Mainly used for Computer Aided Design (CAD) and Computer Aided
Manufacturing (CAM) applications such as printing outs of houses or
car parts.
Also used with AUTOCAD.
Two types of plotters are: drum plotters (where paper moves) and the
flat-bed plotters (where paper is stationary).
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
They are expensive than printers, but can produce more printouts
than standard printers.
Mainly used for Computer Aided Design (CAD) and Computer Aided
Manufacturing (CAM) applications such as printing outs of houses or
car parts.
Also used with AUTOCAD.
Two types of plotters are: drum plotters (where paper moves) and the
flat-bed plotters (where paper is stationary).
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Drum
Plotter
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Flat-bed Plotter
Plotter
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Flat-bed Plotter
Working of Plotters
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Plotters create plots by moving a pen under computer control
over a drafting paper.
•The instructions that a plotter receives from a computer consist
of a color and beginning and end coordinates for a line.
•When an image is to be drawn, a specially designed holder picks
up a pen and takes it over to the start position.
•The pen is pushed down onto the paper and dragged over the
surface to produce straight or curved lines.
•If the product is to be in color, the pen is then replaced with a
new pen. The process continues until the image is complete.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Plotters create plots by moving a pen under computer control
over a drafting paper.
•The instructions that a plotter receives from a computer consist
of a color and beginning and end coordinates for a line.
•When an image is to be drawn, a specially designed holder picks
up a pen and takes it over to the start position.
•The pen is pushed down onto the paper and dragged over the
surface to produce straight or curved lines.
•If the product is to be in color, the pen is then replaced with a
new pen. The process continues until the image is complete.
Advantages
•Plotters can work on very large sheets of paper while
maintaining high resolution.
•They can print on a wide variety of flat materials including
plywood, aluminum, sheet steel, cardboard, and plastic.
•Plotters allow the same pattern to be drawn thousands of
times without any image degradation.
•Best suitable for engineering applications
•It is used to provide the high precision drawing.
•It can produce graphics of various sizes.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Plotters can work on very large sheets of paper while
maintaining high resolution.
•They can print on a wide variety of flat materials including
plywood, aluminum, sheet steel, cardboard, and plastic.
•Plotters allow the same pattern to be drawn thousands of
times without any image degradation.
•Best suitable for engineering applications
•It is used to provide the high precision drawing.
•It can produce graphics of various sizes.
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Disadvantages
•Plotters are quite large compared to a traditional
printer.
•Plotters are also much more expensive than a
traditional printer.
•They do not produce high-quality text printouts
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
•Plotters are quite large compared to a traditional
printer.
•Plotters are also much more expensive than a
traditional printer.
•They do not produce high-quality text printouts
Dept of Computer Science | St Philomena College, Puttur, D.K | [email protected] | www.spcputtur.org
Geetha Poornima K
Dept of Computer Science
St Philomena College Puttur
Dept of Computer Science
St Philomena College Puttur
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