1. Web Browser & External
Devices
DEEPAK JOHN, ASSISTANT LECTURER
DEPARTMENT OF COMPUTING , LYIT
2. Topics to be Covered
1. Introduction To Web Browser
2. Working Of Web Browser
3. Familiarization of top 5 browsers
4. External Devices (Scanner, Printer, Webcam)
5. Conclusion
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3. Introduction to Web Browser
➢ A Web browser acts as an interface between
the user and Web server.
➢ Software application that reside on a
computer and is used to locate and display
pages .
➢ It accesses information provided by web
servers
➢ examples :Google Chrome, Safari, Internet
Explorer(IE)/Edge, Firefox, and Opera.
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1. User Interface
✓ Space where interaction between users and the browser occurs.
✓ this includes the address bar, back/forward button , bookmarking menu etc.
2. Browser Engine
✓ Piece of code that communicates the inputs of user interface with the rendering
engine.
✓ Responsible for querying and manipulating the rendering engine according to
the inputs from various user interfaces
6. 3. Rendering Engine
✓ Rendering, that is display of the requested contents on the browser screen. By
default the rendering engine can display HTML and XML documents and
images.
4. Networking
✓ The fraction of the code written in the browser, responsible to send various
network calls.For example sending the http requests to the server.
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7. 5. Java Script Interpreter
✓ It is the component of the browser written to interpret the java script code
presented in a web page.
6. UI Backend
✓ This draws basic widgets on the browser like combo boxes, windows, etc.
7. Data Storage
✓ It is small database created on the local drive of the computer where the browser
is installed. This database stores various files like cache, cookies, etc.
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HOW WEB BROWSER WORKS
➢Web page has a unique address called a Uniform Resource Locator
(URL).
➢URLs typically include the protocol and the Internet resource (server or
host name).
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1. Browser divides the URL into three parts: protocol, server and domain
name.
2. Browser contacts a domain name server to translate server name into an
IP address.
3. Browser uses IP address to connect to server.
4. Browser uses HTTP to request a page from the server.
5. Server sends the requested page (coded in HTML) to the browser as a
response.
6. Browser reads and interprets the HTML, and displays the Web page.
11. Criteria's for a good browser
➢ Speed: It’s true that many factors, including website design, content and Internet
connection, contribute the loading speed and performance of a website.
➢Compatibility: The browser should be able to load whatever content the website
you’re trying to visit has—without compromising the layout and design as well as
the overall functionality.
➢ Security. Look for a browser that allows you to surf the Internet without the fear
of exposing your personal and private information to various threats and risks.
➢Feature Set. A good Web browser should be able to provide practical features for
their users.
➢Help & Support. Being able to talk to someone regarding issues that you are
experiencing is a huge deal.
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12. Google Chrome
▪ Google Chrome is a web browser developed by Google
▪ Secure, fast and stable faster than other web browser
• Chrome uses up a lot of memory (RAM) when running it.
• If you accidently close the browser, Chrome will close all the tabs opened
without warning.
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13. Safari
▪ Safari is a graphical web browser developed by Apple and included as part of
the Mac OS X operating system.
▪ very good performance with MAC systems
▪ Does not have a restore session feature
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14. Internet Explorer (IE) & Microsoft Edge
▪ According to Microsoft, Microsoft Edge is the fastest browser on the market
with very good performance .
▪ integrates with the Cortana Digital Assistant to offer voice control, search and
personalized info to users.
▪ comes with improved Security
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15. Mozilla Firefox
➢One of the faster and secure way to surf the web
➢ it doesn't allow the user to set the Security Level. The developers designed it
for maximum security level. Firefox uses Googles Blacklist of Phishing and
Malware Sites.
➢ Firefox is easy to use.
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16. Opera
▪ most innovative web browser and Internet suite
▪ It was the first browser to introduce speed dialling, pop-up blocking,
reopening recently closed pages, private browsing, etc.
▪ It has a built-in ad blocker.
▪ "Battery Saver" mode
▪ It has built-in VPN
▪ Opera Turbo: a built-in data compression system
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17. Mobile Browsers
▪ Also called a micro browser, mini browser or wireless internet browser(WIB)
▪ It is a web browser designed for use on a mobile device such as a mobile phone
or PDA.
▪ The two most popular mobile browsers across the globe are Safari and Chrome,
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18. External Hardware Devices
➢ Computer hardware refers to the physical parts of a computer and related
devices. Internal hardware devices include motherboards, hard drives, and RAM.
External hardware devices include monitors, keyboards, mice, printers, and
scanners.
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19. Scanner
➢ The device that translates hard copy into soft copy or converting a document into
digital format.
➢ Components
i. Glass Plate and Cover
ii. ii. Scanning head
1. Light source and mirror
2. Stabilizer bar
3. CCD (Charge Coupled Device) or CIS (Contact Image Sensor)
iii. Stepper Motor
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20. Considerations for Scanner Selection
1. Centralized or De-Centralized Scanning
2. Document Type
3. Cost/Speed/Size
4. Imaging Quality
5. Software Compatibility
6. Service Cost/Ease of Service/Warranty
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21. Flatbed scanners
▪ also known as desktop scanners.
▪ most widely used one
▪Similar to Xerox machine. The image
or document must be placed face down
on the glass plate of the scanner.
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22. Sheet Fed Scanners
▪ This scanner is used for scanning
sheets of papers.
▪ It can not scan bound documents.
We can not scan books. Document
should be fed into the scanner.
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23. Slide Scanners
▪ We can scan photo with the help of a slide
scanner.
▪ The basic use of these scanners is digitalization of
photographs.
▪ Cost and effectiveness of scanning is high.
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24. Drum scanners
▪ The costly and high quality application
scanner.
▪ widely used for commercial graphics
production as well as applications that turn
photos into posters and wall-sized images.
▪ It captures the image with analog light,
producing the most detail possible in each
color channel and then converts it to a
digital file.
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25. Printer
➢A printer is an output device that produces text and graphics on paper.
➢We can connect a printer to computer by using printer cable or a USB cable or
Bluetooth or Wi-Fi.
➢In addition, a few modern printers can directly interface to electronic media
such as memory card, or to image capture devices such as digital camera.
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26. Components of printer
1. Control panel: Controls various printer functions.
2. Cartridge cover: Hold the ink cartridges in place. Open only when installing
or replacing ink cartridges.
3. Print head: Delivers ink to the paper.
4. USB / card slots
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27. ➢Type Of Printer: divided into two main groups,
1. impact printer: produces text and images when tiny wire pins on print head
strike the ink ribbon by physically contacting the paper.
2. Non-impact printer :produces text and graphics on paper without actually
striking the paper.
➢ Printers can also be categorized based on the print method or print technology.
The most popular ones are inkjet printer, laser printer, dot-matrix printer and
thermal printer.
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28. Factors affecting print quality
1. DPI: It is a measurement of printer’s resolution indicating how many ink dots can be
placed by the printer in one square inch. The higher the DPI, the sharper is image.
2. Type of printer: Each type of printer has its own capabilities of printing. Some types
of printers produce high quality print while other produce low quality print.
3. Print Mode: The printing mode may also affect the quality. For example the draft
mode increases the print rate but quality is reduced.
4. Toner: The quality and amount of toner also affects print quality
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29. Dot Matrix Printer
▪ The term dot matrix refers to the process of
placing dots to form an image.
▪ This is the cheapest and the most noisy
printer and has a low print quality.
▪The dot matrix forms images one character
at a time as the print head moves across the
paper.
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30. How Dot-Matrix works
▪Uses tiny pins to hit an ink ribbon and the paper much as a
typewriter does.
▪ This printer arranges dots to form characters and all kinds of
images.
▪ 9 to 24 vertical column pins are contained in a rectangular
print head.
▪ When print head moves across the paper, pins are activated to
form a dotted character image.
▪ These printers can produce carbon copies along with the
originals.
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31. Ink-Jet Printer
▪It is a non-impact printer producing a high quality print.
▪A standard Inkjet printer has a resolution of 300dpi. Newer models have further
improved dpi.
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32. How Inkjet Printer works
1. Print head having four ink cartridges moves .
2. Software instructs where to apply dots of ink, which colour and what quantity
to use.
3. Electrical pulses are sent to the resistors behind each nozzle.
4. Vapor bubbles of ink are formed by resistors and the ink is forced to the paper
through nozzles.
5. A matrix of dots forms characters and pictures.
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33. Laser Printer
▪ Laser printers can print text and images in high speed and high quality
resolution, ranging from 600 to 1200 dpi.
▪ A laser beam projects an image of the page to be printed onto an electrically
charged rotating drum coated with selenium.
▪ Laser printers produce very high-quality print and are capable of printing an
almost unlimited variety of fonts.
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34. How Laser printer Works
1. Paper is fed and the drum rotates.
2. A laser beam conveys information from the computer to a rotating mirror and thus an
image is created on the drum.
3. The charges on the drum are ionized and the toner sticks to the drum.
4. Toner is transferred from drum to paper.
5. Heat is applied to fuse the toner on the paper.
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35. Thermal Printer
▪ Thermal printers are inexpensive
printers mostly used in fax machines and
barcode priting .
▪The heat activates the thermo-sensitive
colouring layer of the thermo-sensitive
paper, which manifests a pattern of
colour change in response.
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36. Multi-function printer
▪ A MFP is an all purpose device that
prints, faxes, copies and scans.
▪ A single multi function printer can replace
several bulky devices.
▪ These printers use inkjet technology and
provide high quality print but at slow
speed.
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37. Web cam
▪ Webcam is a device used to capture images, audio and videos.
▪ Webcam are either inbuilt or can be externally attached with the laptop or the
computer.
▪ frame rate determines the quality of webcam
▪Frame rate indicates the number of pictures the software can grab and transfer in
one second. For streaming video, you need a minimum rate of at least 15 frames
per second (fps), and 30 fps is ideal.
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38. There are two types of webcams
1. Basic webcams :These are not a good choice
to stream 24/7, high quality, real-time video
as they are typically intended for video chat
and only work if they are connected to a
computer.
2. IP Network Webcams: Also known as
network cameras. Network cameras has own
IP-address These can be placed anywhere on
an IP network and do not require a
computer. These cameras can be used
wirelessly and are the industry standard in
live webcam streaming.
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