Software Tools

UNIT-5
Software tools : Specification methods, interface – Building Tools. 8
Interaction Devices –Keyboard and function keys – pointing devices – speech
recognition digitization and generation –image and video displays – drivers.
 Software tools used in HCI are applications or programs that help designers and
developers create user interfaces, test their usability, and evaluate their
performance. Some of the commonly used software tools in HCI are

Specification methods - These are methods used to specify the GUI, such as
grammars, state transition diagrams, or task models. They provide a way to describe
the structure, behavior, and functionality of the interface.
Interface building tools - These are tools that allow designers to create and modify
the interface using graphical or textual elements, such as widgets, menus, buttons,
etc. They can be either low-fidelity (such as paper sketches or mockups) or high-
fidelity (such as interactive prototypes or final products).
Interaction devices - These are devices that enable users to interact with the
interface, such as keyboards, mice, touch screens, speech recognition, etc. They can
affect the usability and accessibility of the interface, depending on the user’s
preferences and needs.
Evaluation tools - These are tools that help measure and improve the quality of the
interface, such as usability testing, user feedback, analytics, etc. They can provide
quantitative or qualitative data on the user’s satisfaction, efficiency, effectiveness,
and errors.
 What is Software Tool?
• A software tool is a system program that interfaces a program with the entity
generating its input data or interfaces the results of a program with the entity
consuming them.

• It is a set of computer programs used by developers to create, maintain, debug, or

support other applications and programs.
It can be code editors, language libraries, debuggers, performance analysis tools, GUI
designers, etc.

• There are some factors that need to be considered before selecting a software tool
like the usefulness of the tool, company criteria, integration of one tool with another,
etc.
• Software tools assist in all the activities of the software lifecycle.

• These are used to accomplish and investigate the business processes, document the
development process, and optimize all the processes.

• These help developers easily maintain the workflow of the project.

 Evolution of Software Development Tools

• The evolution of software development tools

has been driven by the need to improve
efficiency, accuracy, and collaboration in the
software development process. As software
development has become more complex and
specialized, tools have been developed to
address specific needs and challenges.
software development tools have evolved significantly over the past several decades, as advances
in technology have led to new capabilities and improved performance. Here are some key
milestones in the evolution of software development tools:
The 1960s: The first computer programming languages, such as FORTRAN and COBOL, are
developed, along with early text editors and compilers.
The 1970s: The rise of personal computers and the development of new programming languages,
such as C and Pascal, lead to the creation of more advanced software development tools,
including integrated development environments (IDEs) and debuggers.
The 1980s: The introduction of graphical user interfaces (GUIs) and the widespread adoption of
personal computers leads to the development of tools that are easier to use and more
visually appealing.The
The 1990s: The emergence of the World Wide Web and the development of new programming
languages, such as Java and Python, led to the creation of tools for web development,
including web browsers and HTML editors.
The 2000s: The rise of mobile devices and the development of new platforms, such as iOS and
Android, lead to the creation of tools for mobile app development, including IDEs and
emulators.
The 2010s: The proliferation of cloud computing and the emergence of new programming
languages, such as Go and Swift, lead to the development of tools for cloud development,
including cloud IDEs and containerization tools.
The 2020s: The rise of artificial intelligence and machine learning leads to the development of
tools for developing and deploying machine learning models, such as notebooks and model
serving platforms.
 Common Software Development Tools Types

Software tools are programs or applications that assist in

the development, testing, and maintenance of
software. Some common software development tools
include:
Integrated Development Environments (IDEs): IDEs are
specialized software tools that provide a complete
environment for software development, including a text
editor, compiler, debugger, and other tools.
Source Code Management (SCM) tools: SCM tools allow
developers to manage and track changes to their source
code, as well as collaborate with other team members.
Debugging tools: Debugging tools allow developers
to identify and fix errors in their code.
Test automation tools: Test automation tools allow
developers to automate the testing process,
making it more efficient and accurate.
Project management tools: Project management
tools help developers to plan, track, and manage
their software development projects.
Collaboration tools: Collaboration tools allow
developers to communicate and work with other
team members remotely.
Static code analysis tools: Static code analysis tools
analyze source code for potential issues, such as
security vulnerabilities or coding errors.
Performance analysis tools: Performance analysis tools
help developers to identify and optimize the
performance of their software.
Documentation tools: Documentation tools help
developers to create and maintain documentation for
their software projects.
Configuration management tools: Configuration
management tools help developers manage and track
software configuration changes.
Why do Software Development Tools Matter?

Below are some of the reasons for using software

development tools:
Increases productivity: Software development tools matter
because they help developers to be more productive,
efficient, and accurate. They also help to ensure the
quality and reliability of the software being developed.
Helps to create quality software efficiently: Software
development tools are important because they help
developers create high-quality software more efficiently
and effectively. These tools can help with tasks such as
writing and organizing code, debugging and testing code,
and collaborating with other team members.
Saves time and effort: Good software development tools can save time
and effort by automating repetitive tasks and providing helpful features
such as code completion, refactoring, and debugging tools. This can
allow developers to focus on more important tasks, such as solving
complex problems and implementing new features.
Helps to write reliable and maintainable code: Software development
tools can help developers write more reliable and maintainable code by
providing features such as static analysis, unit testing, and integration
testing. This can help prevent bugs and other issues from being
introduced into the codebase and can make it easier to catch and fix
problems when they do occur.
Supports team collaboration: Many software development tools include
features that support team collaboration, such as version control
systems, code review tools, and project management tools. These tools
can help teams work together more effectively, by allowing them to
track changes to the codebase, coordinate their work, and share ideas
and feedback.
Range of tools provides variety: Different software development tools are better suited to
different types of projects, programming languages, and platforms. Having a range of
tools available can allow developers to choose the best tool for the job, and can make it
easier to adapt to changing needs or requirements.
Where are Development Tools found?
Software development tools can be found in a variety of places, including online
marketplaces, software development platform websites, and as standalone applications
that can be downloaded and installed on a local machine.
Online marketplaces: Some popular online marketplaces for software development tools
include the Apple App Store, Google Play Store, and Microsoft Store. These
marketplaces offer a wide range of tools, including IDEs, text editors, version control
systems, and more.
Software development platform websites: Software development platform websites, such
as GitHub, GitLab, and Bitbucket, also offer a range of tools that are specifically
designed for use with their platform. These tools may include version control systems,
collaboration tools, and integrations with other software development tools.
Free or open-source tool: Standalone software development tools can also be downloaded
and installed on a local machine. These tools may be available as free or open-source
software, or they may require a purchase or subscription. Some popular standalone
software development tools include IDEs, text editors, and version control systems..
 10 Best Software Development Tools
Below are some of the software development tools:
1. Git: A version control system that allows developers to track changes to their
code and collaborate with other team members. Features include branching,
merging, and merging conflicts.
2. IntelliJ IDEA: A popular integrated development environment (IDE) for Java
development, with support for a wide range of programming languages and
frameworks. Features include code completion, refactoring, and debugging
tools.
3. Eclipse: Another popular IDE, with a focus on Java development but support for
a range of other languages as well. Features include code completion,
refactoring, and debugging tools.
4. Visual Studio: A comprehensive IDE from Microsoft, with support for a wide
range of programming languages and platforms. Features include code
completion, refactoring, debugging, and integration with other Microsoft tools.
5. PyCharm: An IDE specifically designed for Python development, with support for
scientific computing and data science tools. Features include code completion,
debugging, and integration with version control systems.
6. Xcode: The IDE for Apple’s platforms, including macOS, iOS, iPadOS, watchOS, and
tvOS. Features include code completion, debugging, and integration with Apple’s
development tools.
7. Android Studio: The official IDE for Android development, with support for building,
testing, and debugging Android apps. Features include a visual layout editor,
emulator, and integration with Google’s developer tools.
8. Node.js: A JavaScript runtime built on Chrome’s V8 JavaScript engine, allowing
developers to run JavaScript on the server side. Features include support for
asynchronous programming and a large ecosystem of open-source libraries.
9. npm: The default package manager for the Node.js runtime, allowing developers to
easily install and manage third-party libraries and dependencies. Features include
version management and automatic dependency resolution.
10. Gradle: A build automation tool for Java and other programming languages,
allowing developers to automate the process of building, testing, and deploying
their code. Features include support for multiple languages and platforms and
integration with a range of tools.
 Interactive device
• QWERTY Layout
Dvorak layout
• ABCD Style Keyboard
• Interaction Devices- Keyboard Layouts
• QWERTY layout
• – 1870 Christopher Latham Sholes
• – good mechanical design and a clever placement of the letters that
• slowed down the users enough that key jamming was infrequent
• – put frequently used letter pairs far apart, thereby increasing finger
• travel distances
• Dvorak layout
• – 1920
• – reduces finger travel distances by at least one order of magnitude
• – Acceptance has been slow despite the dedicated efforts of some
• devotees
• – it takes about 1 week of regular typing to make the switch, but most
• users have been unwilling to invest the effort
• ABCDE style
• – 26 letters of the alphabet laid out in alphabetical order no typists
will
• find it easier to locate the keys
• Additional keyboard issues
• – IBM PC keyboard was widely criticized because of the placement
of a
• few keys
• • backslash key where most typists expect SHIFT key
• • placement of several special characters near the ENTER key
• – Number pad layout
• – wrist and hand placement
 Keys

• – 1/2 inch square keys

• – 1/4 inch spacing between keys
• – slight concave surface
• – matte finish to reduce glare finger slippage
• – 40- to 125-gram force to activate
• – 3 to 5 millimeters displacement
• – tactile and audible feedback important
• – certain keys should be larger (e.g. ENTER, SHIFT,CTRL)
• – some keys require state indicator, such as lowered position or light
• indicator (e.g. CAPS LOCK)
• – key labels should be large, meaningful, permanent
• – some "home" keys may have additional features, such as deeper cavity
• or small raised dot, to help user locate their fingers properly (caution -
• no standard for this)
 Direct-control pointing devices light pen

• – enabled users to point to a spot on a screen and to perform

a select,
• position, or another task
• – it allows direct control by pointing to a spot on the display
• – incorporates a button for the user to press when the cursor
is resting on
• the desired spot on the screen
• – light pen has three disadvantages: users' hands obscured
part of the
• screen, users had to remove their hands from the keyboard,
and users had to pick up the light pen.
• Touch screen
• – allows direct control touches on the screen using a finger
• – early designs were rightly criticized for causing fatigue, handobscuring-
• the- screen, hand-off-keyboard, imprecise pointing, and the
• eventual smudging of the display
• – lift-off strategy enables users to point at a single pixel
• – the users touch the surface
• – then see a cursor that they can drag around on the display
• – when the users are satisfied with the position, they lift their fingers off
• the display to activate
• – can produce varied displays to suit the task
• – are fabricated integrally with display surfaces
 Indirect pointing devices

• mouse
– the hand rests in a comfortable position, buttons on the mouse are easily
pressed, even long motions can be rapid, and positioning can be precise
• trackball
– usually implemented as a rotating ball 1 to 6 inches in diameter that moves
cursor
• joystick
– are appealing for tracking purposes
• Graphics tablet
– A touch-sensitive surface separate from the screen
• Touchpad
– built-in near the keyboard offers the convenience and precision of a touch
screen while keeping the user's hand off the display surface
 Function Keys on Keyboard

• Function keys are on keyboard which cause operating system

to command interpreter or an application to perform certain
actions on the screen. There are 12 keys on the keyboard from
F1 to F12. All keys are having different functions to perform. If
you are using laptop then you have to press Fn key along with
other keys from F1 to F12 for use.
• Previously, Apple Macintosh computers lacked function keys.
Their new keyboards, on the other hand, have F1 through F12
or F1 through F19 keys at the top. Some MacBook models
include a Touch Bar, which displays digital function keys when
the Fn key is pressed.
• F1 through F12 are the function keys on today’s standard PC
keyboards. Some customized PC keyboards include 24
function buttons labeled F1 through F24.
• F1 through F19 are the function keys on many Apple desktop
computer keyboards with a number pad.
 Use of Keyboard Function Keys (F1 – F12)

• F1 Key
• F1 key is used to open help center. If you are using keyboard of your computer, then only
pressing F1 will work, but if you are using your laptop keyboard then pressing Function key
(FN) with F1 will open help center. With this help center, if you want to know about any
software or application or anything you can get help from there.
• F2 Key
• F2 key is used to rename folder or file. If you want to change name of folder, then you don’t
have to right-click on it, and then find rename option. You can simply click F2, and it will
work properly. This function key will save time of use.
• Alt + Ctrl + F2 command opens document window in Microsoft Office. In Microsoft office
Ctrl + F2 displays print preview window. In Microsoft excel Alt + F2 opens ‘Save As’ window.
Shift + F2 add comment box in Microsoft Excel.
• F3 Key
• F3 key is used to search application on computer or laptop. If you are doing it on your
laptop, then pressing function key (FN) and F3 together will work. It will take you to search
box where you can search application.
• Another use of F3 is that if you want to search text while using web browser, then also this
key is used to search text. In Microsoft Word, Shift + F3 transform text from upper case to
lower case or all capital letters.
• F4 Key
• F4 key does not work alone. Pressing only F4 will not work whether it is on computer or
laptop. Pressing Alt + F4 together works to close current application which is open on
screen. Also, pressing both keys together while on desktop screen, then there shut
down, restart option appears.
• Alt + F4 used to close current window. If no program is open, it shutdown dialog box.
Ctrl + F4 used to close active window.
• F5 Key
• F5 key is used to refresh screen. When you want to refresh screen, you have to go to
desktop screen and then click refresh button, but F5 will simply do this work. Going to
web browser, you want to refresh that website or that screen, F5 will refresh that. This
will save time of user.
• F6 Key
• F6 key is used to decrease volume if you are using this on laptop. If you are searching on
web browser, and want to jump to any URL, then F6 will work. In Microsoft word, Ctrl +
F6 toggles between various documents
• F7 Key
• F7 key is used basically in MS Office apps like PowerPoint, excel to find grammar
mistakes in it. In Microsoft Office, Shift + F7 opens Research window.
• F8 Key
• F8 key is used to go in safe mode. For example, if you are starting your laptop, then
pressing F8 there will help you to go in safe mode. If you are using this key on word, then
• F9 Key
• F9 key alone has no work in Windows. It is basically used in MS Word with Alt
and Shift. In Microsoft Word, Ctrl + F9 and Alt + F9 build mail merge
document.
• F10 Key
• F10 key also does not have any use in Windows. It is used in MS Word with
Shift. Pressing these both keys together, shortcut menu appears on screen.
Shift + F10 used to open up the menu window, similar to right-click on mouse.
• F11 Key
• F11 key is used for full screen. If you want to use your browser then open that
browser and press F11, for full-screen mode and can be get back to original
screen by pressing ESC.
• Shift + F11 adds a new sheet in Microsoft Excel, Ctrl + F11 used to add new
macro to the workbook. In MS Office program Alt + F11 invokes Microsoft
Visual Basic window.
• F12 Key
• When pressed, without FN key on laptop, then laptop will go in flight mode.
F12 key basically does not have any use on computers. It is used in MS Word.
When pressed, it automatically shows dialog box to save file.
• In MS Office, Shift + Ctrl + F12 open Print window. Ctrl + F12 used to open a
• How the keys are organized
• The keys on your keyboard can be divided into several groups based on function:
• Typing (alphanumeric) keys. These keys include the same letter, number,
punctuation, and symbol keys found on a traditional typewriter.
• Control keys. These keys are used alone or in combination with other keys to
perform certain actions. The most frequently used control keys are Ctrl, Alt, the
Windows logo key , and Esc.
• Function keys. The function keys are used to perform specific tasks. They are
labeled as F1, F2, F3, and so on, up to F12. The functionality of these keys differs
from program to program.
• Navigation keys. These keys are used for moving around in documents or webpages
and editing text. They include the arrow keys, Home, End, Page Up, Page Down,
Delete, and Insert.
• Numeric keypad. The numeric keypad is handy for entering numbers quickly. The
keys are grouped together in a block like a conventional calculator or adding
machine.
 Pointing Devices

• In the early days of computers, commands and data were input via a keyboard. On early
computer monitor screens, the text entry position was denoted by a blinking underscore or
vertical bar, called a cursor. At first, users had no control over the location of this cursor;
later, directional arrow keys and key commands allowed users to select text entry points. In
more recent operating systems that utilize a graphical user interface (GUI) , the cursor still
indicates the point where text may be entered, but it is also a visible and moving on-screen
pointer controlled with an input device, such as a mouse. The computer operator uses
the pointing cursor to establish where the position indicator cursor should be placed, or to
select a program to run or file to view. Typically, the pointing cursor appears on the screen
as an arrow.
• Since early computer use keyboard commands were difficult to learn and cryptic to non-
computer specialists, computer manufacturers and software developers quickly embraced
the point-and-click interfaces first popularized by the Apple Macintosh. However, keyboard
arrows were no longer adequate as a way to move a cursor around the screen. The point-
and-click concept required the user to move something that would cause a corresponding
movement on the screen. This led to the development of input devices such as the mouse,
the joystick, and other tools for controlling on-screen movement of the cursor. Although
the mouse and its descendants are not replacements for the keyboard, they do
supplement the keyboard in tasks for which it is ill suited.
• Common Pointing Devices
Common pointing devices used to control on-screen movement include computer
mice, touch pads, touch screens, joysticks, graphics tablets, and trackballs. Some of
these devices, including the mouse and the joystick, can be added to a computer
system according to the needs of a user. Other devices, such as touch screens, are
integrated into specialized computer systems designed for particular purposes.
• Computer Mouse.
A computer mouse is a small, hand-held, interactive input pointing device that,
when rolled over a flat surface, controls placement of the cursor on a computer
display. A computer mouse is analogous to a live mouse in that it is palm-size and
mouse-shaped, with rounded corners. Originally, all mice were connected to
computers with a wire suggestive of a tail; however, cordless mice are also
available now.
• A mouse can be a one-, two-, or three-button device. After a user positions the
cursor on the computer display by moving the mouse, screen action can be
controlled by single or multiple clicks of the mouse buttons. Screen icons can be
activated with one click, or dragged across the computer display by a single click
that is held as the mouse is moved from one location to another.
• Touchpads.
• Where using a mouse would be awkward, such as in a laptop computer configuration,
or cursor movement is more important than characters, touchpads have become
popular. These are generally built into a computer unit, and they often include clickable
buttons that correspond to the buttons of a mouse. Beneath the top layer of the
touchpad are two or more layers separated by a non-conducting dielectric ; each layer
contains a grid of electrode rows and columns. The different layers create a capacitance
(electric field) between them that may be drastically changed by the electric field of a
human finger either touching or moving near the touchpad. Changes in capacitance are
measured 100 times a second and translated into cursor movement.
• Touch Screens.
• A touch screen is a computer display screen that is sensitive to human touch, allowing
the screen to function as an input pointing device. The user touches the screen itself to
cause some action to take place.
• There are three types of touch screen technology. A resistive touch
screen panel is coated with a thin, metallic, electrically conductive
and resistive layer that causes a change in the electrical current
that is registered as a touch event and sent to the controller for
processing. A surface wave touch screen uses ultrasonic waves that
pass over the touch screen panel. When the panel is touched, a
portion of the wave is absorbed and this change in the ultrasonic
waves registers the position of the touch event and sends this
information to the controller for processing. A capacitive touch
screen panel is coated with a material that stores electrical charges.
When the panel is touched, a small amount of charge is drawn to
the point of contact. Circuits located at each corner of the panel
measure the charge and send the information to the controller for
 Speech recognition

Speech recognition is an interdisciplinary subfield

of computer science and computational linguistics that
develops methodologies and technologies that enable
the recognition and translation of spoken language
into text by computers. It is also known as automatic
speech recognition (ASR), computer speech
recognition or speech to text (STT). It incorporates
knowledge and research in the computer
science, linguistics and computer engineering fields.
The reverse process is speech synthesis.
 History
• Pre-1970
• 1952 – Three Bell Labs researchers, Stephen Balashek, R. Biddulph, and K. H. Davis built
a system called "Audrey" for single-speaker digit recognition. Their system located
the formants in the power spectrum of each utterance.
• 1960 – Gunnar Fant developed and published the source-filter model of speech
production.
• 1962 – IBM demonstrated its 16-word "Shoebox" machine's speech recognition
capability at the 1962 World's Fair.
• 1966 – Linear predictive coding (LPC), a speech coding method, was first proposed
by Fumitada Itakura of Nagoya University and Shuzo Saito of Nippon Telegraph and
Telephone (NTT), while working on speech recognition.
• 1969 – Funding at Bell Labs dried up for several years when, in 1969, the
influential John Pierce wrote an open letter that was critical of and defunded speech
recognition research.This defunding lasted until Pierce retired and James L. Flanagan
took over.
• Raj Reddy was the first person to take on continuous speech recognition as a graduate
student at Stanford University in the late 1960s. Previous systems required users to
pause after each word. Reddy's system issued spoken commands for playing chess.
• mid-1980s IBM's Fred Jelinek's team created a voice activated
typewriter called Tangora, which could handle a 20,000-word
vocabulary Jelinek's statistical approach put less emphasis on
emulating the way the human brain processes and understands
speech in favor of using statistical modeling techniques like
HMMs. (Jelinek's group independently discovered the
application of HMMs to speech.) This was controversial with
linguists since HMMs are too simplistic to account for many
common features of human languages. However, the HMM
proved to be a highly useful way for modeling speech and
replaced dynamic time warping to become the dominant
speech recognition algorithm in the 1980s
• 1987 – The back-off model allowed language models to use
multiple length n-grams, and CSELT used HMM to recognize
languages (both in software and in hardware specialized
processors, e.g. RIPAC).
• 1984 – was released the Apricot Portablewith up to 4096 words
support, of which only 64 could be held in RAM at a time.
• 1987 – a recognizer from Kurzweil Applied Intelligence
• 1990 – Dragon Dictate, a consumer product released in
1990 AT&Tdeployed the Voice Recognition Call Processing
service in 1992 to route telephone calls without the use of a
human operator. The technology was developed by Lawrence
Rabiner and others at Bell Labs.
• In the 2000s DARPA sponsored two speech
recognition programs: Effective Affordable
Reusable Speech-to-Text (EARS) in 2002
and Global Autonomous Language
Exploitation(GALE).
• Dynamic time warping (DTW)-based speech
recognition
 Speech generation

– Michaels and Wiggins (1982) suggest that speech generation is

"frequently preferable" under these circumstances:
• The message is simple.
• The message is short.
• The message will not be referred to later.
• The message deals with events in time.
• The message requires an immediate response.
• The visual channels of communication are overloaded.
• The environment is too brightly lit, too poorly lit, subject to
severe vibration, or otherwise unsuitable for transmission of
visual information.
• The user must be free to move around.
• The user is subjected to high G forces or anoxia
 Audio tones, audio libation, and music

• – Sound feedback can be important:

• • to confirmations
• • offer warning
• • for visually impaired users
• • music used to provide mood context, e.g. in games
• • can provide unique opportunities for user, e.g. with
• simulating various musical instruments
• Displays – Small and Large
• • The display has become the primary source of feedback to the user
• from the computer
• – The display has many important features, including:
• • Physical dimensions (usually the diagonal dimension and depth)
• • Resolution (the number of pixels available)
• • Number of available colors, color correctness
• • Luminance, contrast, and glare
• • Power consumption
• • Refresh rates (sufficient to allow animation and video)
• • Cost
• • Reliability
 Usage characteristics distinguish displays:

• • Portability
• • Privacy
• • Saliency
• • Ubiquity
• • Simultaneity Display technology
• • Monochrome displays
• – are adequate, and are attractive because of their
lower cost
• • RGB shadow-mask displays
 Display Devices in Computer Graphics
• The display device is an output device used to represent the information
in the form of images (visual form). Display systems are mostly called
a video monitor or Video display unit (VDU).
• Display devices are designed to model, display, view, or display informatio
n. The purpose of display technology is to simplify information sharing.
• Today, the demand for high-quality displays is increasing.
• There are some display devices given below:
• Cathode-Ray Tube(CRT)
• Color CRT Monitor
• Liquid crystal display(LCD)
• Light Emitting Diode(LED)
• Direct View Storage Tubes(DVST)
• Plasma Display
• 3D Display
Cathode-ray Tube (CRT): Here, CRT stands for Cathode ray tube. It is a technology which is used in traditional
computer monitor and television.
Cathode ray tube is a particular type of vacuum tube that displays images when an electron beam collides on
the radiant surface.
Component of CRT
Electron Gun: The electron gun is made up of several elements, mainly a heating filament (heater) and a
cathode. The electron gun is a source of electrons focused on a narrow beam facing the CRT.
Focusing & Accelerating Anodes: These anodes are used to produce a narrow and sharply focused beam of
electrons.
Horizontal & Vertical Deflection Plates: These plates are used to guide the path of the electron the beam. The
plates produce an electromagnetic field that bends the electron beam through the area as it travels.
Phosphorus-coated Screen: The phosphorus coated screen is used to produce bright spots when the high-
velocity electron beam hits it.
There are two ways to represent an object on the screen:
Raster Scan: It is a scanning technique in which the electron beam moves along the screen. It moves from top
to bottom, covering one line at a time.
A raster scan is based on pixel intensity control display as a rectangular box on the screen called a raster.
Picture description is stored in the memory area called as Refresh buffer, or Frame Buffer.
Frame buffer is also known as Raster or Bitmap. Raster scan provides the refresh rate of 60 to 80 frames per
second.
For Example: Television
The beam refreshing has two types:
Horizontal Retracing
Vertical Retracing
When the beam starts from the top left corner and reaches bottom right, and again
return to the top left, it is called the vertical retrace.
It will call back from top to bottom more horizontally as a horizontal reversal.
Advantages:
Real image
Many colors to be produced
Dark scenes can be pictured
Disadvantages:
Less resolution
Display picture line by line
More costly
2. Random Scan (Vector scan): It is also known as stroke-writing display or calligraphic
display.In this, the electron beam points only to the area in which the picture is to be
drawn.
It uses an electron beam like a pencil to make a line image on the screen. The image is
constructed from a sequence of straight-line segments. On the screen, each line
segment is drawn by the beam to pass from one point on the screen to the other,
where its x & y coordinates define each point.
After compilation of picture drawing, the system cycle back to the first line and create
 What are Display Drivers?

• Display Drivers are the components that make the

interaction between your computer and your hardware
possible. Some programs require the use of specialized
display drivers, such as video games and image
manipulation applications. Advanced display drivers are
necessary for media programs that rely on the visual
display to function properly. Without them, a software
program may crash, fail to load, or crash altogether. In
these situations, it is important to have the proper
display driver installed before continuing to use your
computer.
• A display driver is a software or hardware interface
that provides the necessary connection between
your computer’s display and the microprocessor or
controller. Many devices come with display drivers
built in, and some have driver verification built-in. In
some cases, software upgrades detect your device
and provide an updated driver. In such cases, you
might not need to update your display driver every
time you install a new version of your software. But
it is important to always update your display driver
to ensure it works with your computer.