Accessibility Features, Networking, and Internet Security
Accessibility Features in Microsoft Windows
StickyKeys
StickyKeys is an accessibility feature to help computer users with physical disabilities. It is also used by others as a means to reduce repetitive strain.
FilterKeys
FilterKeys is a feature of Microsoft Windows. It is an accessibility function that tells the keyboard to ignore brief or repeated keystrokes, making typing easier for people with hand tremors.
ToggleKeys
ToggleKeys is also a feature of Microsoft Windows. It is an accessibility function designed for people who have vision impairment or cognitive disabilities. When ToggleKeys is turned on, the computer emits sound cues when the locking keys (Caps Lock, Num Lock, or Scroll Lock) are pressed. A high sound is emitted when the keys are switched on and a low sound is emitted when they are switched off.
SoundSentry
SoundSentry is designed to help users with auditory impairments. SoundSentry generates visual warnings, such as a blinking title bar or a flashing border, whenever the computer generates a sound.
ShowSounds
ShowSounds instructs applications that convey information by sound to also provide information visually, through text captions or informative icons.
High Contrast
High Contrast is an accessibility feature to assist people with vision impairment. You can change the size and color of fonts and the background for ease of viewing.
Cursor Options
Cursor Options is also an accessibility feature that assists people with vision impairment by changing the blink rate and width of the cursor.
MouseKeys
MouseKeys is an accessibility feature that assists people who have difficulty using a mouse. This option uses the keyboard (especially the numeric keypad) as a pointing device instead of a mouse.
SerialKeys
SerialKeys is an accessibility feature that assists people that have difficulty using a keyboard or a mouse (or both). They can use special devices such as sip, puff, and breath switches to provide input to the computer through serial ports.
Computer Networks and the Internet
Introduction to Networking
A computer network is a collection of computers and other hardware components interconnected by communication channels (cables or satellites) that allow sharing of resources and information. This section introduces you to the basic fundamental concepts of networking and the internet and using different types of internet connection.
Types of Networks
Peer-to-Peer (P2P) Networks
In peer-to-peer (P2P) networks, all computers have an equal status. Generally, in such a network, each terminal has an equally competent CPU.
Client-Server Networks
In client-server networks, certain computers have special dedicated tasks, providing services to other computers in the network. The computer(s) which provide services are called servers and the ones that use these services are called clients.
Local Area Network (LAN)
A local area network (LAN) connects computers and devices in a limited geographical area such as a home, school, computer laboratory, office building, or closely positioned group of buildings. Usually, local area networks offer very high speeds and are used for connecting computers and peripherals such as printers, scanners, etc.
Wide Area Network (WAN)
A wide area network (WAN) covers a broad area (i.e., any network that links across metropolitan, regional, or national boundaries). The internet is the most popular WAN and is used by businesses, governments, non-profit organizations, individual consumers, artists, entertainers, and many others.
The Internet
The internet is a global system of interconnected computer networks that use the standard internet protocol suite to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks.
World Wide Web (WWW)
The World Wide Web (abbreviated as WWW or W3, commonly known as the web) is a system of interlinked hypertext documents accessed via the internet. With a web browser, one can view web pages that may contain text, images, videos, and other multimedia, and navigate between them via hyperlinks. Information is stored on web servers. Pages are retrieved by using a web browser such as Firefox on the local computer. A web browser is software used to view websites and acts as an interface between the user and the World Wide Web. A web server is a computer that stores websites and their related files for viewing on the internet.
Advantages of Networking
- Data Sharing: One of the most important uses of networking is to allow the sharing of data. Users can send text files, spreadsheets, documents, presentations, audio files, video files, etc. to other users.
- Hardware Sharing: Hardware components such as printers, scanners, etc. can also be shared. For example, instead of purchasing 10 printers for each user, one printer can be purchased and shared among multiple users, thus saving cost.
- Internet Access Sharing: You can purchase a single internet connection and share it among other computers in a network instead of purchasing multiple internet connections for each computer. This is very commonly found in internet cafes (browsing centers), schools, colleges, companies, etc.
- Usage of network-based applications such as web browsers, email clients, chat applications, audio and video calling, etc. is another advantage.
Internet Connections and Service Providers
To use the internet, you need an internet connection. Internet connections are provided by internet service providers (ISPs) such as Bharat Sanchar Nigam Limited (BSNL), Airtel, MTS, Vodafone, Tata Docomo, etc.
An internet service provider (ISP) is an organization that provides you with access to the internet via a dial-up (using a modem) or direct (hard-wired) or wireless connection.
Modem
A modem is a device that converts digital computer signals into a form (analog signals) that can travel over phone lines. It also re-converts the analog signals back into digital signals. The word modem is derived from its function: modulator/demodulator.
Dial-up
Dial-up internet access is a form of internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an internet service provider (ISP) via telephone lines using a device called a modem. Users dial a particular number provided by the ISP and gain access to the internet. Dial-up connections are extremely slow and in most cases, it is replaced by a high-speed connection such as DSL or cable modem.
DSL
Digital Subscriber Line (DSL) provides internet access by transmitting digital data over wires of a local telephone network. DSL service is delivered along with wired telephone service on the same telephone line. On the customer premises, a DSL filter removes the high-frequency interference, enabling simultaneous use of the telephone and data transmission. For using a DSL connection, you need a DSL modem and a subscription.
Cable Internet Access
Cable internet access is a form of broadband internet access that uses the cable television infrastructure. Cable internet access is provided through existing cable TV networks; this is similar to DSL that is provided over existing telephone lines.
3G
3G, short for 3rd Generation, is a set of standards used for mobile devices and mobile telecommunication services and networks. High-Speed Downlink Packet Access (HSDPA) is a 3G mobile telephony communications protocol that allows higher data transfer speeds and capacity. If support for 3G is available on your mobile phone, you can subscribe to the 3G connectivity with your ISP to get a high-speed internet connection on your phone.
WiMAX
WiMAX (Worldwide Interoperability for Microwave Access) is a wireless communications standard designed to provide mobile broadband connectivity across cities and countries through a variety of devices. WiMAX is a long-range system, covering many kilometers and is typically used where DSL or cable internet access cannot be used; this could be due to difficulty in laying out cables for homes or offices located in remote locations but need access to the internet.
Wi-Fi
Wi-Fi is a popular technology that allows an electronic device such as computers or mobile phones to exchange data wirelessly over a network, including high-speed internet connections. Wi-Fi devices such as personal computers, smartphones, video game consoles, etc. can connect to a network resource such as the internet through a device called the Wireless Access Point (WAP). Wi-Fi is used where cables cannot be run (such as old buildings, outdoor areas) to provide network and internet access. Wi-Fi can also be used where users require mobile connectivity.
Data Transfer on the Internet
The data is broken up into bits of same-sized pieces called packets. A header is added to each packet explaining where the data has come from, where it should end up, and where it fits in with the rest of the packets. Each packet is sent from computer to computer until it finds its destination. Each computer on the way decides where next to send the packet. All packets may not take the same route. At the destination, the packets are examined. If any packets are missing or damaged, a message is sent asking for them to be re-sent. This continues until all packets have been received intact. The packets are now reassembled into their original form. All this is done in seconds!
Accessing Wi-Fi
To access Wi-Fi, you need an access point with an active internet connection. Usually, when you subscribe to an internet connection, the ISP provides options to purchase or rent a Wi-Fi router that can act as both an internet connectivity device and an access point for Wi-Fi connectivity. Setting up a Wi-Fi network requires technical expertise; however, you can access the Wi-Fi network by connecting to an access point that is already set up for use.
Instant Messaging (IM)
Instant messaging (IM) is a form of communication over the internet that offers an instantaneous transmission of text-based messages from sender to receiver.
Key Features of Instant Messaging
- Text messages can be sent to one or more persons (similar to SMS)
- Audio calling and conferencing
- Video calling and conferencing
- File transfers (not limited to documents, spreadsheets, audio files, video files, etc.)
- Message history (save messages for future reference)
Types of Instant Messaging Software
- Application-based: Downloaded and installed on the user’s computer. Examples: Google Talk, Yahoo! Messenger, Skype, Windows Live Messenger, Rediff Bol, etc.
- Web-based: Accessed using browsers such as Internet Explorer, Mozilla Firefox, Google Chrome, etc. Examples: Meebo, Yahoo! Messenger for the web, MSN Web Messenger, IMO, etc.
Blogs
A blog is a discussion-style site used by non-technical (and technical) users for creating personal web pages. Blogs are similar to an online personal diary and simple to use. You can use a blog to convey messages about events, announcements, news, reviews, etc. Blogs are usually managed using a web browser and this requires an active internet connection. You can also use offline blog software to create content first and later publish the content when an active internet connection is available.
Offline Blog Editors
If you do not have an active internet connection, you can create blogs using a blog application and publish the blog whenever internet connectivity is available. There are several free offline blog editors available that can be downloaded and installed on the local computer such as: Quamana, Windows Live Writer, Blogdesk.
Online Shopping
Online shopping is a form of electronic commerce where customers can buy or sell goods over the internet. Customers need to have an active internet connection for viewing goods or services offered by a seller; customers can pay online using a credit or debit card.
Internet Security
Internet security is a branch of computer security specifically related to the internet, often involving browser security but also network security. Its objective is to establish rules and measures to use against attacks over the internet. The internet represents an insecure channel for exchanging information leading to a high risk of intrusion or fraud, such as phishing. This section introduces you to internet security concepts and how to secure online and network transactions.
Best Practices for Internet Security
You can reduce the risks by using best practices such as using antivirus software, antispyware software, firewalls, strong passwords, etc. in addition to spreading awareness of the best practices.
Strong Passwords
- Keep the length of the password at least 12-14 characters if permitted.
- Avoid keeping passwords based on repetition, dictionary words, letter or number sequences, usernames, relative or pet names, etc.
- Include numbers and symbols in passwords if allowed.
- Use capital and lower-case letters.
- Avoid using the same password for multiple sites or purposes.
- Avoid using something that the public or workmates know you strongly like or dislike.
- Use random password generators if possible.
Data Backup
Always keep copies of personal data in additional media such as compact discs, pen drives, etc. This could be helpful in situations when there is a loss of data. Keep the data away from unauthorized users. Use encryption software (usually available within the operating system) to protect your data from unauthorized users. If encryption software is not available within the operating system, use third-party software.
Keeping Your Username and Password Private
Never save your username or password on computers that are used in shared environments such as internet cafes. Browsers may save your personal data on the local computer that can be used by another user using the same computer.
Registering with Websites
Read the privacy statement or policy whenever you register with a website. The statement or policy will include information about how the website uses personal data.
Do Not Share Personal Information
Websites require you to fill out forms containing fields such as name, gender, age, email address, school, etc. Be cautious when filling out such forms; research and verify if it’s a trustworthy website. Your email address could be used by unauthorized users to send you fake or unwanted emails; think twice or thrice before providing information to any website and decide if it is really necessary.
Secure Transactions
If you’re using online shopping or transactions, websites even store your credit card or online banking personal information such as your credit card number, account details, etc. This information can be tracked and used by unauthorized users, often known as hackers, to misuse this information. Again, ensure the website is legitimate and uses secure practices for performing and maintaining online transactions. Since information such as credit card details or personal information is sent over the network, it is always recommended to use only secure websites for such transactions. Verify if the website uses secure transactions; usually, it is indicated through a digital certificate represented as a golden lock in the web browser’s address bar.
Use Antivirus and Antispyware Software
Computers are prone to attacks from software known as malware that could harm your computer. Malware tracks browsing behavior or transmits personal data from your computer; programs such as keyloggers could be installed on your computer to track and transmit every key that is pressed on a keyboard (keystrokes) to unauthorized users. Antivirus and antispyware programs also offer real-time protection, monitoring your computer for any changes by malware software. Keep your antivirus and antispyware software always up to date; this can help in protecting your computer from recent threats.
Do Not Immediately Respond to Emails from Unknown Users
It may be a fake email trying to gather personal information such as your bank account details, home address, etc. Some emails could promise you jobs or announce lottery results which in turn could compromise the user. And in some cases, viruses or scripts that are dangerous could be attached to the email; never open the attachment from an unknown source.
Clear Browser Cookies Frequently
Cookies are programs that are created on your local computer when you visit websites. Though cookies are meant for storing data based on your activity performed during your earlier visit such as login details, details of a shopping cart, visited pages in a website, etc., they could also be tracked by unauthorized users and possibly gain access to your personal information.
Keep the Operating System and Software Applications Up to Date
Though operating systems and applications are designed, tested, and distributed, sometimes they may have security holes through which a hacker can take advantage; they may track and gather information or even damage the whole computer. In general, most vendors notify the users whenever a security hole is identified and an update is available to address that particular issue. You can also visit the respective vendor’s website to check if there are any updates available, download and keep your operating system and software applications up to date, free from security holes.
Install Firewalls
Firewalls could be software or hardware and can assist in keeping a computer and a network secure. Firewalls analyze the network traffic and determine if the traffic should be allowed or not. In most cases, operating systems such as Linux, Windows, or Mac include firewall software as a part of the operating system, thus keeping the computer secure. In rare cases, you may need to configure your firewall for additional security.
Never Install Software from Unknown Sources
As they might not be trustworthy; download only from well-known or reputed websites. Verify the source if it is legitimate by searching the internet or referring to comments from other users before downloading them; understand the nature and the purpose of the software before attempting to download and install them.
Remove Unwanted or Unknown Software Applications
These might have gotten installed without your knowledge when you have visited some websites. Unwanted software could get installed as they might have been bundled along with necessary software. Some programs such as toolbars get installed usually through bundled software and are programmed to send personal data without your consent.
MS-Excel
AutoSum
AutoSum is used for adding the values given in cells automatically without writing the formula to perform the operation.
Conditional Formatting
Conditional formatting allows you to change the formatting (font color, border, shading) of the cells based on the values in it. Yes, you can do that manually, but it can be a tiresome task if you have a huge amount of data. So, you specify a condition for the values in the cell, and if the condition is satisfied then automatically the formatting of the cell changes. This feature would be very useful if you were working on a profit and loss spreadsheet, or a temperature variance spreadsheet, or a marksheet. You could highlight cells that have values greater than a defined rule with one color and those less than another with a different color. Basically, you can select one or more cells, and create rules (conditions) for when and how those cells are formatted. The conditions can be based on the selected cell’s contents, or based on the contents of another cell. You can control the following formats:
- Number format
- Font, font style, and font color (but not font size)
- Fill color and fill pattern
- Border color and border style (but not border thickness)
Freezing Rows and Columns
Freezing rows and columns is another helpful feature in a spreadsheet. When you’re dealing with a huge amount of data that spans several rows or columns, you may want the headers to remain constant (frozen) while you scroll through the data so that you can see the identifying names of the rows/columns.
Hiding Rows and Columns
- In order to hide any row or column you can either select the particular row or column that is to be hidden or just one cell in the corresponding row or column (for example B3).
- Click on the Format option available under the Cells group in the Home tab.
- A dropdown list appears.
- Click on Hide & Unhide > Hide Rows.
- In order to unhide the row or column that is hidden you have to select any cells before and after the cell that is hidden then click Unhide Rows in the Format option available under the Home tab.
Freezing Rows and Columns
- Open a new spreadsheet.
- In order to freeze rows or columns click on the Freeze Panes option available under the Window group in the View tab.
- A drop-down list appears. Click on Freeze Panes. Doing so will freeze all the rows above and all the columns to the left of the selected cell.
Page Layout Options
To set the page layout options, do the following:
- Click on the Page Layout option under the Workbook Views group on the View tab.
- You can set the following:
- Margins
- Orientation
- Page headers and footers
- Hide or display gridlines
- Size of the page
- Define the print area
- Specify the background
- Click on the Margins option under the Page Setup group, a dropdown list will appear.
- You can either select any one of the predefined margin options available or else you can define your own margin settings by clicking the Custom Margins option. A dialog box appears.
- You can set the margin values manually from the options available under the dialog box.
- You can set the orientation of the page to either portrait or landscape by clicking the Orientation option under the Page Setup group in the Page Layout tab.
- You can set the size of the page by clicking the Size option under the Page Setup group in the Page Layout tab.
- You can specify the area to be printed by selecting the area and then clicking the Print Area option under the Page Setup group in the Page Layout tab. A drop-down list appears.
- Click on Set Print Area to set the selected area to get printed. You can also clear the print area by clicking the Clear Print Area option.
- You can specify a background for your sheet using the Background option under Page Setup in the Page Layout tab.
Spreadsheet Views
There are five types of views available in the spreadsheet:
- Normal View: The default view of the spreadsheet application is the normal view. It’s a collection of cells arranged in the work area.
- Page Layout View: You can select the page layout view to quickly fine-tune a worksheet that contains many charts or huge amounts of data and achieve professional-looking results.
- Page Break Preview: This option is similar to the page layout option except you can set the area that is to be set as a page after inserting a page break.
- Custom Views: If you would like to view selected areas of a document, you can use the custom view option. For example, if you would like to point out a certain row and column, you can add that to the custom view.
- Full Screen: Selecting this option makes the workbook cover the entire screen. All tabs are hidden from view. To get back the tabs, click on File > Restore.
Multiple Windows
Additionally, in a spreadsheet, you can open multiple windows that display the current spreadsheet and then arrange those windows in a variety of ways. You can also open and arrange multiple workbook windows.
Charts
A chart is a graphical representation of data, in which the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart. A chart can represent tabular numeric data, functions, or some kinds of qualitative structures. A spreadsheet enables you to create, modify and format charts based on the data given in the spreadsheet. In this exercise, you will learn how to create, modify and format charts using the spreadsheet.
Chart Elements
A chart has many elements; however, only some of the elements are displayed by default. Following is a description of the elements used in the above chart:
- Chart Area of the Chart
- Plot Area of the Chart
- Data Points that are plotted in the chart
- Horizontal and Vertical Axis in the chart
- Legend of the chart
- Chart and Axis Title used in the chart
- Data Label for identifying details of the data point in the chart
Chart Types
- Bar Charts: A bar chart (horizontal bars) emphasizes the comparison between items at a fixed period of time. This chart type also includes cylinder, cone, and pyramid subtypes.
- Column Charts: A column chart, unlike a bar chart to which it is often compared, emphasizes variation over a period of time. This chart type also includes cylinder, cone, and pyramid subtypes.
- Line Charts: A line chart shows the relationship of the changes in the data over a period of time.
- Pie Charts: Pie charts contain just one chart data series. A pie chart shows the relationship of the parts to the whole.
- Area Charts: An area chart shows the relative importance of values over time.
- XY (Scatter) Charts: Scatter charts are useful for showing a correlation among the data points that may not be easy to see from data alone.
Sort and Filter
Sort is a feature that helps you arrange the selected data either in ascending or descending order. Filter is a feature used for extracting particular data using some conditions. Spreadsheets offer both these features for sorting and filtering data in the spreadsheet.