Computer basics
A computer is defined as a device that accepts input, processes data, stores data, and produces output, all according to a series of stored instructions. Input is what is typed, submitted, or transmitted to a computer system, either by a person, the environment, or another person. Data represents facts, objects and ideas that can be processed or manipulated with computer programs known as software. Most of this processing takes place in a component known as the CPU – central processing unit, or the computer’s brain. Memory is the area within a computer that temporarily holds data for processing while the computer’s storage area is where data is stored on a more permanent basis. Output is what is produced by a computer.
Today’s computers work by loading a set of instructions into memory from a stored program and then allowing those instructions to be executed to produce output. This concept allows you to use your computer for multiple tasks, such as word processing, image editing, sending e-mails, and much more.
Nearly all of today’s computers use some type of microprocessor, or single chip CPU, so the older classifications of microcomputer, minicomputer, and mainframe computer to classify computers are no longer used today. Computers are now categorized based on their intended use and physical sizes. Typical categories include personal computers, handheld computers, workstations, videogame consoles, mainframes, supercomputers, and servers.
A personal computer is one designed to meet the computing needs of an individual person, usually those computers for e-mail, word processing, and internet access. Personal computers can be desktop computers, notebooks, or tablet computers. A personal computer system usually contains a system unit, display devices, keyboard, mouse, floppy disk drive, hard disk drive, CD and DVD drives, sound card and speakers, modem, and a printer. A detailed description and picture of each of these items can be found on page 10 of your textbook.
A desktop computer is one that is found in homes and offices and typically fits on or under a desk with a separate computer screen, keyboard, and mouse. A notebook computer, or laptop, is a small, lightweight personal computer that incorporates all of its parts in a single unit, also capable of operating on a battery. A tablet computer is a portable computer featuring a touch-sensitive screen that can be used or writing or drawing.
A handheld computer features a small keyboard or touch-sensitive screen and is designed to fit into your pocket. These types of computers, or PDAs (personal digital assistants) are designed for keeping track of addresses and appointments. More information about the latest PDA models, prices, software, and accessories can be found by visiting the PDA InfoWeb.
One definition of the computer category workstation is a powerful computer designed to do a particular task, such as medical imaging, computer-aided design, etc. Another definition of the category is any ordinary personal computer connected to a network. A computer network is two or more computers and other devices connected to share data, programs, and hardware, typically through a LAN (local area network), or a network located in a limited geographical area.
Videogame consoles such as Xbox, PlayStation, and GameCube are also computers. These computers are equipped with microprocessors and produce graphics that rival some powerful workstation computers.
Mainframe computers are large and expensive computer systems capable of processing data for hundreds of thousands of users. Mainframes are very expensive and are used when reliability, data security, and centralized control are necessary.
A supercomputer is one that when it is created, is one of the fastest in the world. Supercomputers are able to perform tasks that no other computer can do. Supercomputers are used to model world-wide weather systems, simulate nuclear explosions, etc. Supercomputers are typically constructed of thousands of microprocessors and can cost upwards of $100 million. Additional information about supercomputers can be found by visiting the Supercomputer InfoWeb.
Servers are computers or hardware devices whose purpose is to “serve” data to other computers connected through a network. A personal computer, workstation, or software package that requests data from a server is known as a client. Just about any computer can be configured to run as a server.
In terms of computers, data is defined as the symbols that represent people, events, things, and ideas. Data turns into information when it is presented in a format that people can understand and use. Data is stored within a computer in a digital form, or series of 1s and 0s. Each 1 or 0 is called a bit and it takes 8 bits to form a byte, which is equivalent to a single character – letter, number, or punctuation mark.
Files are a named collection of data that exists on a storage medium, such as a hard drive, floppy disk, or CD-ROM. Data files contain data for processing while executable files contain programs or instructions that tell the computer how to do something. You can determine what type of file a given file is by looking at its extension, or the last 3 letters after the dot (period) in the filename. Executable files typically have the .exe extension while data files will have a variety of extensions, determining their type.
Application software is a set of computer programs that help a person carry out a given task. An operating system is essentially the master controller of all activities that take place on a computer. Operating systems are classified as system software, not application software. Some of the most popular operating systems for personal computers today include Microsoft Windows and Mac OS. Linux and Unix are popular operating systems for servers.
Two of the most important factors that influence application and device compatibility that define a computer’s platform are the microprocessor and the operating system. PCs are based on the design of the original IBM PC and typically serve the Windows platform. Macs are based on a proprietary design manufactured by Apple Computer, Inc.

Internet basics
The Internet is a network of interconnected communications lines for transporting data around the world. The main routes of the Internet are known as the Internet backbone, and the backbone is constructed and maintained by companies such as AT&T and Sprint. Local telephone systems, cable television companies, etc. play a major role in creating regional Internet connection lines.
Communication is made possible through all of the devices connected to the various companies’ lines on the Internet through a standard called TCP/IP (Transmission Control Protocol/Internet Protocol), a standard set of rules for electronically addressing and transmitting data.
The information that is available on the Internet is stored on various servers worldwide, which are owned by businesses, schools, organizations, government agencies, and even individuals. Internet resources include Web sites, search engines, downloads and uploads, P2P (peer-to-peer) file sharing, e-mail, bulletin boards, blogs, chat groups and instant messaging, internet telephony, e-commerce, broadcasts, and remote access and control. If you would like to check out some of these resources, be sure to visit the Internet Resources InfoWeb.
To access everything that is available on the Internet, you must first connect your computer to the Internet. There are many different options available for connecting your computer to the Internet, including through a dial-up connection and a modem. A modem is a device in your computer system that converts a computer’s digital signals into analog for transmission across a phone line. When you wish to connect to the Internet through a modem, your computer dials a special access number, which is answered by an Internet modem. The fastest speed available to typical dial-up connections is 56Kbps, meaning 56,000 bits of data per second. This speed is good for e-mail, e-commerce, and chat, but not so good for Internet video and intense graphics.
Cable companies are now offering high-speed, broadband, connections to home users through coaxial cable lines. Cable modem service requires two pieces of equipment – a network card and a cable modem. The network card is a device designed to connect a personal computer to a LAN, which your computer becomes a part of with a cable modem service. The cable modem is a device that changes the signals from the computer into a form that can travel over cable TV lines. This type of service is referred to as an always-on connection because when your computer is on, it is connected to the Internet, whereas with a modem, you have to dial through a phone line and “hang up” your connection to talk on the phone. Cable modem speeds can reach 1.5Mbps (1.5 million bits per second), or about 25x faster than a dial-up connection.
Other high-speed access options that are available include ISDN (Integrated Services Digital Network) and DSL (Digital Subscriber Line). ISDN is not much faster than dial-up access, but costs substantially more, making it a low ranking technology in today’s times for home use. DSL can connect at speeds twice as fast up to 125x as fast as a 56Kbps modem. Both ISDN and DSL require a proximity to telephone switching stations, which means not everyone can gain access to these services. An alternative for those who live in a rural area is DSS (Digital Satellite Service) which can reach speeds up to 500Kbps.
To access the Internet, you also must connect to an Internet Service Provider (ISP). An ISP is a company that maintains Internet computers and equipment to provide access to businesses, home users, etc. typically for a monthly fee. A local ISP is a company that provides Internet access within a limited geographical region while a national ISP, such as AOL, can offer the same service across the country. To find a list of ISPs that provide access in your area, check your local Yellow Pages directory. Before selecting an ISP, you should consider a variety of factors, including geographical coverage, type of service, quality of service, cost of monthly service, cost of equipment and installation, extra services, and customer service, all of which are summarized on page 21 of your textbook.
Access to the Internet is usually restricted in various ways, including through the use of user IDs and passwords by ISPs. In this way, ISPs are able to limit access to their paying customers. A user ID is a series of characters that become a person’s unique identifier. A password is a different series of characters that verifies your identity. In most cases, a person is allowed to choose their own user ID, but some services will assign you a user ID, which may be case sensitive, meaning that the user IDs and password differentiate on lowercase and uppercase letters.
Usually, an ISP, or even your school, will assign you an initial password when you receive your user ID. This password should be changed to one that could not be “guessed” or “discovered” by someone else. Your password should be a sequence of characters that are easily remembered by you, but that would be difficult for someone else to guess. You should consider keeping two passwords – one for high-security use and one for low-security – because various Web sites that are available require the establishment of a password for site access. Page 23 of your textbook provides a nice summary of Dos and Don’ts for selecting a password.

Web basics
Once you have gained access to the Internet, you can then start to explore the many resources available to you, including the Web. The Web is short for the World Wide Web, which is a collection of files that can be accessed through HTTP (HyperText Transfer Protocol) using a software program called a Web browser. Web-based files are typically called Web pages these pages contain links, or hyperlinks, that allow users to click the links to move between pages. A series of Web pages can be grouped into a Web site, or virtual “place” on the Internet. Web sites are hosted by computers all over the world called Web servers.
Every Web page has its own unique address called a URL (Uniform Resource Locator). Most URLs begin with http:// to indicate that the page uses the HTTP protocol. Most Web sites will have a doorway to other pages in their Web site, and this doorway is accessed through their main URL. For example, CNN has a Web site that can be accessed via the URL http://www.cnn.com/. A particular Web page within CNN’s site may be accessed through the URL http://www.cnn.com/showbiz/movies.htm. HTTP is the Web protocol standard, www.cnn.com is the Web server name or domain name, showbiz is the folder name, and movies.htm is the name of the particular Web page being viewed. Remember that the slashes in a URL go in one direction, known as a forward slash. Web pages typically end in the .htm or .html file extension, which represents the fact that the page is an HTML document, a standard format for Web documents.
A Web browser is a software program that runs on your computer system that is used to access Web pages. Two of the most popular Web browsers today are Microsoft Internet Explorer and Netscape Navigator. For up-to-the-minute information on Web browsers, see the Browser InfoWeb.
Despite user interface differences and variations in terminology, Web browsers typically offer the same set of standard features to their users. Page 29 of your textbook contains a list of these standard features for working with Web pages.
When you want to view a Web page, you enter its URL into the address box of a browser and hit enter. If you have formatted the URL correctly, the server where the page is located is contacted and the contents of the file will be returned to your Web browser. The information returned contains the information you wish to view and the formatting codes for the page, called HTML tags. These tags tell your browser how to display the page. An example showing what the original HTML file looks like with tags as compared to how the page looks when displayed in a browser can be found on page 30 of your textbook.
You can copy sections from Web pages into your own documents, providing copyright clearance or proper citing, by highlighting text with your mouse in a Web page and selecting Copy from the Edit menu of the Web browser program. You can then paste this information into another program, such as a word processor, by going to that program’s Edit menu and selecting Paste.
To help you find Web pages related to various topics of interest to you, there are search engines on the Web, such as Google and Yahoo!, that allow you to find Web sites for visiting by entering queries. A query describes information you want to find by providing keywords, or search terms, to the search engine. Search engines store information about Web pages in a large database that is searched when you enter keywords into a search engine’s query area, but this can cause thousands of unmanageable results to be returned. To aid with searches, search engines also allow you to use search operators to define relationships between keywords to narrow the listing of results available. A listing of search operators is found on page 32 of your textbook. Additional information about search engines can be found at the Search Engine InfoWeb.
Topic directories are sites that list topics by category and hierarchically categorize sites based on topics and sub topics. An example of a topic directory is Yahoo! (http://www.yahoo.com/) which also serves as a search engine.
If you do not like the fact that you may have to enter a cryptic query into a search engine to find matching Web pages, you could try a site such as http://www.askjeeves.com/ which allows you to enter a question in English in the way that you would ask the question of a human.

E-mail basics
E-mail, or electronic mail, is the technology that caused the Internet to take off. The Internet delivers nearly 15 billion e-mails each year around the world. Anyone with an e-mail account can send and receive e-mail. An e-mail account provides you with an e-mail address and storage space for e-mail messages (mailbox). An e-mail address consists of a user ID, and @ symbol, and the name of the computer which stores the mailbox. A person’s e-mail user ID could be the same as the user ID they are issued by an ISP, or it could be assigned by a school, business, etc. For example, if Missy Morgan’s user ID at Marshall University was missy_morgan and Marshall’s server name was marshall.edu, her e-mail address would be missy_morgan@marshall.edu.
An e-mail message is a document composed on a computer consisting of a message header and body. The header contains who you are sending the e-mail to (their address), your return address, and a subject line. The body of the message contains the information you are sending to the recipient, including the possibility for sending them files from your computer system, called attachments.
Basic e-mail activity includes the composing (writing), reading, replying to, and forwarding of e-mail messages. If you receive a message that you wish to send to someone else, e-mail programs provide a button that says Forward that will allow you to send the message by just entering someone’s e-mail address without having to retype the message.
E-mail was originally developed to store and send ASCII text across the Internet, but since its inception, you can now covert any file you wish through MIME (Multi-Purpose Internet Mail Extensions) into ASCII code for sending across the Internet. Any file that travels with an e-mail message is known as an e-mail attachment.
Most e-mail programs will allow you to create e-mail messages in HTML, meaning you can format the messages as you type them, instead of sending them in plain text format. In addition to this formatting and the attaching of files to e-mail messages, most e-mail programs typically offer features that help you perform the tasks that are contained in the listing on page 38 of your textbook.
Because e-mail messages are composed without facial expressions, voice inflections, and body gestures, one must carefully consider their audience and message that is to be conveyed. Netiquette is online jargon for Internet etiquette, which can help you avoid some of the pitfalls with online communications. This series of customs or guidelines for maintaining communications are contained on page 39 of your textbook.
An e-mail system is defined as the equipment and software that carries and manipulates e-mail messages. This includes an e-mail server that stores, sorts and routes mail, and also the personal computers that send and receive the e-mail. E-mail is based on store-and-forward technology, which means that individuals cannot receive their messages directly from other senders without it first being stored on the e-mail server.
There are three types of e-mail systems that are used today – POP, IMAP, and Web-based mail. POP (Post Office Protocol) temporarily stores messages in your mailbox on a server. When you request the messages, they are downloaded to your PC. IMAP (Internet Messaging Access Protocol) is similar to POP, but you can leave your messages on the e-mail server so that they can be accessed from multiple computers. Web-based e-mail keeps your mail on a Web site instead of ever transferring it to your computer. To use Web-based e-mail, you need an e-mail account with a Web-based e-mail provider, such as Yahoo! or Hotmail. Most Web-based e-mail accounts are free. Additional information can be found on Web-based E-mail at the Web-based E-mail InfoWeb. Even though you can choose to use Web-based e-mail, you are usually forced to use either POP or IMAP depending on what your ISP offers. A POP server that stores POP messages requires users to use a POP e-mail client program, such as Microsoft Outlook Express or Qualcomm Eudora to access those messages. When sending messages from your e-mail client program, they are stored in an Outbox on your computer until they are routed through an SMTP server (Simple Mail Transfer Protocol) instead of a POP server. Think of POP for incoming and SMTP for outgoing. A nice illustration of this process can be seen on page 41 of your textbook.
One advantage of e-mail client programs and the POP protocol is that you can compose and read e-mail while you are not connected to the Internet, and once you have reconnected, the messages that you composed can be sent. However, with Web-based e-mail, you must be connected to the Internet in order to read and compose messages. So, which system should you choose to use? A POP or Web-based system? Your choice should be based on such factors as control, security, and travel, each of which are summarized on page 42 of your textbook.

Techtalk: The boot process
The sequence of events that take place between the time that you turn on your computer and that it is ready to use is known as the boot process. This process involves flashing lights, whirring noises, and beeping as your computer performs what is called a power-on self-test (POST). This boot process can warn you if something is wrong with your computer and also loads your operating system from the hard drive of a computer into the volatile random accessory memory (RAM) section of a computer’s memory.
There are six major events that take place during the boot process of a computer, including: power up, start the boot program, power-on self-test, identify peripheral devices, load the operating system, and check the configuration and customization.
If you were to boot your computer and the operating system will not load, you may see an error on your screen detected by the POST to let you know what happened. You may also hear a beep code if the screen is not functioning which will signal what problem you may be encountering. Beep codes are machine dependent and can be referenced through your computer’s reference manual.
The first time an error is encountered during the boot process, try rebooting your computer to see if the computer boots normally the second time. If it does not, you may want to check the manufacturer’s Web site for information, including any patches that may need to be made or installed, or contact your manufacturer’s technical support department.
If after a computer boots the operating system starts to act erratically, you may have to reinstall your operating system, or you may have contracted a computer virus (more on this in Chapter 4). In some cases, a computer may be booted in Safe Mode for the more technically savvy computer owners to solve their own problems. More on Safe Mode can be found through the Safe Mode InfoWeb.

Issue: E-mail privacy?
Have you ever worried about your e-mail being read by others before it reaches its intended recipient? Technically, it can be, but the Electronic Communications Privacy Act of 2000 prohibits the use of intercepted e-mail as evidence unless a judge approves a search warrant. However, the Patriot Act, passed in 2001, has provided the federal government a means for lowering fourth amendment standards for obtaining e-mail logs. The FBI has developed a technology known as Carnivore which can scan messages entering and leaving an ISP’s e-mail system to find e-mail associated with a person under investigation. Privacy advocates are concerned because the technology scans all messages.
What about employers? They have the right to monitor employees e-mail without a court order. Even if you delete an e-mail message, it can still be saved on an employer’s mail server. Like employees, students who use a school’s e-mail system cannot be assured of e-mail privacy. So why would an employer or school be concerned about your e-mail? Because the owner of the e-mail system can be held responsible for the contents of messages sent through its servers. This is why many businesses and schools have created e-mail privacy policies, and made those policies available to anyone with accounts on their servers.
Computers in context: Homeland security
Once a localized problem affecting the Middle East and South Asia, terrorism is now spreading around the globe. Governments in many countries are devoting significant resources to combat this growing threat. In the U.S., the Department of Homeland Security is responsible for reducing America's vulnerability to terrorism and leading a unified national effort to prevent terrorist attacks on American citizens and assets.
Technology is a key component of the DHS strategy. Electronic sniffing devices in airports detect explosives. The PROTECT system, designed to be deployed in subways, uses chemical detectors to sense toxic fumes, video surveillance cameras to monitor subway-train and passenger status, a computer program to predict the dispersion of toxic materials, and a wireless communications system to coordinate emergency responders.
Terrorists might use cell phones or e-mail to communicate and plan attacks. The National Security Agency uses electronic intercepts to monitor worldwide “chatter.”
Homeland security efforts are producing job opportunities in government agencies and the private sector.