PC Basics 9 Figure 1-3 Motherboard ■ Read-only memory (ROM)—A type of computer memory in which data has been prerecorded. After data has been written onto a ROM chip, it cannot be removed and can only be read. A version of ROM known as EEPROM (electron- ically erasable programmable read-only memory) can be written to. It is called Flash memory or firmware. The basic input/output system (BIOS) in most PCs is stored in EEPROM. ■ Expansion slot—An opening in a computer, usually on the motherboard, where an expansion card can be inserted to add new capabilities to the computer (see Figure 1-4). ■ System unit—The main component of the PC system. It includes the case, chassis, power supply, microprocessor, main memory, bus, expansion cards, disk drives (floppy, CD hard disk, and so on), and ports. The system unit does not include the keyboard, the monitor, or any other external devices connected to the computer. ■ Power supply—Supplies power to a computer. 1102.book Page 9 Tuesday, May 20, 2003 2:53 PM 10 Chapter 1: Introduction to Networking Figure 1-4 Expansion Slot Motherboard Components The motherboard is the computer’s main circuit board. It is crucial because it is the nerve center of the computer system. Everything else in the system plugs into it, is con- trolled by it, and depends on it to communicate with other devices in the system. The following list describes the motherboard’s various components: ■ Backplane—A large circuit board that contains sockets for expansion cards. ■ Memory chips—RAM chips on memory cards plug into the motherboard. ■ Network interface card (NIC)—A printed circuit board that provides network communication capabilities to and from a PC. Many newer desktop and laptop computers have an Ethernet NIC built into the motherboard. ■ Video card—A board that plugs into a PC to give it display capabilities. Video cards typically include onboard microprocessors and additional memory to speed up and enhance graphics display. ■ Sound card—An expansion board that handles all sound functions. ■ Parallel port—An interface that can transfer more than 1 bit at a time. It is used to connect external devices, such as printers. ■ Serial port—An interface used for serial communication in which only 1 bit is transmitted at a time. The serial port can connect to an external modem, plotter, or serial printer. It can also be used to connect to networking devices such as routers and switches as a console connection. ■ Mouse port—Connects a mouse to a PC. ■ Keyboard port—Connects a keyboard to a PC. N O TE Some computers have a network card, sound card, video card, and other cards integrated into the motherboard. 1102.book Page 10 Tuesday, May 20, 2003 2:53 PM PC Basics 11 ■ Power cord—Connects an electrical device to an electrical outlet to provide power to the device. ■ Universal Serial Bus (USB) port—This interface lets peripheral devices such as mice, modems, keyboards, scanners, and printers be plugged in and unplugged without resetting the system. USB ports eventually might replace serial and paral- lel ports. Desktop Versus Laptop Laptop and notebook computers are becoming increasingly popular. The main differ- ence between desktop PCs and laptops, other than the fact that laptop components are smaller than those found in a PC, is that laptops offer more mobility and portability than desktop PCs. The expansion slots are called Personal Computer Memory Card International Association (PCMCIA) card slots or PC card slots in laptop computers. The PC card slots are where devices such as NICs, modems, hard drives, and other useful devices (usually the size of a thick credit card) are connected. Figure 1-5 shows a PC card adapter for a wireless local-area network (WLAN). Figure 1-5 PC Card Lab Activity PC Hardware This lab helps you become familiar with the basic peripheral components of a PC system and their connections, including network attachment. You examine the internal PC configuration and identify major components. You also observe the boot process for the Windows operating system and use the Control Panel to find out information about the PC hardware. 1102.book Page 11 Tuesday, May 20, 2003 2:53 PM 12 Chapter 1: Introduction to Networking Network Interface Cards As shown in Figure 1-6, a NIC is a printed circuit board that provides network com- munication capabilities to and from a PC. Also called a LAN adapter, a NIC plugs into a motherboard and provides a port for connecting to the network. The NIC consti- tutes the computer interface with the LAN. Figure 1-6 Network Interface Card The NIC communicates with the network through a cable and with the computer via an expansion slot. When a NIC is installed in a computer, it requires an interrupt request (IRQ) for service from the CPU, as well as an input/output (I/O) address, a memory space for the operating system (such as Linux or Windows), and drivers to perform its function. An IRQ is a signal that informs a CPU that an event needing its attention has occurred. An IRQ is sent over a hardware line to the microprocessor. An example of an interrupt being issued is a key being pressed on the keyboard. The CPU must move the character from the keyboard to RAM. An I/O address is a location in memory used to enter data into or retrieve data from a computer using an auxiliary device. When selecting a NIC for a network, consider the following: ■ Type of network—Different types of networks use different types of NICs. For example, Ethernet NICs are designed for Ethernet LANs. Some other types of networks include Token Ring and Fiber Distributed Data Interface (FDDI). Ethernet is by far the most common. ■ Type of medium—The type of port or connector used by the NIC for network connection is specific to the medium type, such as twisted-pair, coaxial, fiber- optic, or wireless. Coaxial is becoming increasingly rare. 1102.book Page 12 Tuesday, May 20, 2003 2:53 PM PC Basics 13 ■ Type of system bus—There are different types of system buses, such as PCI and ISA. Because PCI slots are faster than ISA slots, the latter are being phased out. NIC and Modem Installation Connectivity to the Internet requires an adapter card, which might be a modem or NIC. A modem is an electronic device that is used for computer communications through telephone lines. It allows data transfer between one computer and another over the Public Switched Telephone Network (PSTN). Figure 1-7 shows an example of an external modem. Typically, modems send data in blocks of bytes. After each block, basic math is performed to analyze the block, and the computer on the receiving end is asked whether it agrees with the results. If any differences appear, the block is sent again. The modems convert digital data to analog signals for transmission over the PSTN and then convert analog signals back to digital data on the receiving end. Figure 1-7 External Modem The term modem derives from the function of this device. The process of converting digital signals to analog and back again is called modulation/demodulation (hence the term modem). Modems can be installed internally or attached to the computer via a serial or USB interface externally. Modems connect a computer to the network by dial- ing the telephone number of another computer’s modem, typically that of the Internet service provider (ISP). The NIC lets hosts connect to the network. The NIC is considered a key component. NICs are available in different types, depending on the individual device configuration. Notebook computers can have a built-in interface or use a PCMCIA card. Desktop systems can use a built-in or adapter card-type NIC. 1102.book Page 13 Tuesday, May 20, 2003 2:53 PM 14 Chapter 1: Introduction to Networking Situations that require NIC installation include the following: ■ Adding a NIC to a PC that does not already have one ■ Replacing a bad or damaged NIC ■ Upgrading from a 10-megabits per second (Mbps) NIC to a 10/100-Mbps NIC To install a NIC, as shown in Figure 1-8, you need the following resources: ■ Knowledge of how the adapter is configured, including jumpers and plug-and-play software. Most modern NICs do not require jumpers and are plug-and-play, requiring little or no configuration. They can be configured using software that comes with the NIC if necessary. ■ Use of network card diagnostics, including the vendor-supplied diagnostics and loopback test (see the card’s documentation). ■ The ability to resolve hardware resource conflicts, including IRQ, I/O base address, and direct memory address (DMA), which is used to transfer data from RAM to a device without going through the CPU. Figure 1-8 Installing a NIC Overview of High-Speed and Dialup Connectivity In the early 1960s, modems were introduced to provide data communications connec- tivity for dumb terminals to a centrally based computer. Many companies rented com- puter time because owning an onsite system was cost-prohibitive. The connection rate was very slow—300 bits per second (bps), which translates to about 30 characters per second. As PCs became affordable in the 1970s, Bulletin Board Systems (BBSs) appeared, allowing users to connect and post or read messages on a discussion board. Running at 300 bps was acceptable, because this exceeds the speed at which most people can read or type. BBSs did not become widely used until the early 1980s, and the transfer of 1102.book Page 14 Tuesday, May 20, 2003 2:53 PM Testing Connectivity with Ping 15 files and graphics began to be desirable. The 300 bps speed quickly became intolerable, and modem speeds started to increase. By the 1990s, modems were running at 9600 bps. They reached the current standard of 56 kbps (56,000 bps) by 1998. Inevitably, the high-speed services used in the corporate environment, such as digital subscriber line (DSL) and cable modem access, migrated to the consumer market. These services no longer required expensive equipment or a second phone line. They are also always-on services and therefore provide instant access that does not require a connection to be established for each session. This results in greater reliability and flex- ibility. It has also led to the ease of Internet connection sharing and small office and home networks. TCP/IP Configuration TCP/IP is a set of protocols or rules developed to allow cooperating computers to share resources across a network. A computer must be running the TCP/IP protocol suite to access the Internet. To enable TCP/IP on the workstation, it must be config- ured using the operating system tools. The PC requires an IP address, subnet mask, default gateway, DNS (domain name server) information. These can be assigned man- ually or obtained from a Dynamic Host Configuration Protocol (DHCP) server. The information necessary to configure TCP/IP on a computer is typically obtained from a network administrator or an ISP. The process is similar whether you’re using a Windows or Apple Macintosh operating system. TCP/IP, DHCP, and DNS are covered in subsequent chapters. Testing Connectivity with Ping Ping is a program that is useful for verifying a successful TCP/IP installation. It is named after the sonar operation used to locate and determine the distance to an underwater object. Ping stands for Packet Internet Groper. The ping command works by sending multiple IP packets to a specified destination. Each packet sent is a request for a reply. The output response for a ping contains the success ratio and round-trip time to the destination. From this information, you can Lab Activity PC TCP/IP Network Settings This lab introduces you to the methods of discovering your computer’s net- work connection, host name, MAC (Layer 2) address, and network (Layer 3) address. 1102.book Page 15 Tuesday, May 20, 2003 2:53 PM 16 Chapter 1: Introduction to Networking determine if there is connectivity to a destination. The ping command is used to test the NIC transmit/receive function, the TCP/IP configuration, and network connectivity. The following are some usages of the ping command: ■ ping 127.0.0.1 (internal loopback test)—This verifies the operation of the TCP/IP stack and NIC transmit/receive function. Figure 1-9 shows the ping 127.0.0.1 test. ■ ping IP address of host computer—Verifies the TCP/IP address configuration for the local host. ■ ping default-gateway IP address—Verifies whether the router that connects the local network to other networks can be accessed. ■ ping remote destination IP address—Verifies connectivity to a remote host. Figure 1-9 ping 127.0.0.1 Web Browsers and Plug-Ins A web browser acts on a user’s behalf by ■ Contacting a web server ■ Requesting information ■ Receiving information ■ Displaying the results on the screen Lab Activity Using ping and tracert In this lab, you learn to use the TCP/IP ping and traceroute commands to test connectivity in a network. In the process, you see name resolution occur. 1102.book Page 16 Tuesday, May 20, 2003 2:53 PM Web Browsers and Plug-Ins 17 A web browser is software that interprets Hypertext Markup Language (HTML), one of the languages used to code web page content. Other markup languages, such as SGML and XML, provide more advanced features for creating dynamic and interac- tive web pages than does HTML. HTML, the most common markup language, can display graphics and play sound, movies, and other multimedia files. Hyperlinks are computer program commands that point to other HTML files on a web server or other places in the same documents, which provide shortcuts to other web pages and files. Two of the most popular web browsers are Internet Explorer (IE) and Netscape. Although they are identical in the task they perform, there are differences between them. Some websites might not support the use of one or the other, so it can be beneficial to have both programs installed on the computer. Table 1-1 compares the characteristics of these two web browsers. Standard web browsers cannot display many special, or proprietary, file types. To view these files, the browser must be configured to use plug-in applications. These applica- tions work in conjunction with the browser to launch the program required to view the special files. Here are some of the more popular proprietary plug-ins: ■ Flash Player/Shockwave Player—A plug-in that plays multimedia files created by Macromedia Flash. ■ Adobe Acrobat Reader—A software program that allows the user to view and print Adobe Portable Document Format (PDF) files. ■ Windows Media Player—A software program that allows the user to play audio and video files. ■ Quicktime—A software program created by Apple that allows the user to play video and audio files. ■ Real Player—A software program that allows the user to play audio files. Table 1-1 Microsoft Internet Explorer Versus Netscape Communicator IE Communicator Integrated with other Microsoft products First popular browser Takes up more disk space Takes up less disk space Displays HTML files and performs e-mail, file transfers, and other functions Displays HTML files and performs e-mail, file transfers, and other functions 1102.book Page 17 Tuesday, May 20, 2003 2:53 PM 18 Chapter 1: Introduction to Networking Other Common Computer Applications Computers perform many other useful tasks. In business, employees regularly use a set of applications that come in the form of an office suite, such as Microsoft Office or Lotus Smart Suite. Office applications typically include the following: ■ Spreadsheet software—An application that lets users construct spreadsheets consisting of columns and rows. It is often used with formulas to process and analyze data. ■ A word processor—An application that lets users create and edit text documents. Modern word processors allow the user to create sophisticated documents that include graphics and richly formatted text. ■ Database software—An application that lets users store, maintain, organize, sort, and filter records. A record is a collection of information identified by a common theme, such as a customer name. ■ Presentation software—An application that lets users design and develop presen- tations to deliver at meetings, classes, or sales presentations. ■ Personal information managers—Applications that can include features such as e-mail, contact lists, a calendar, and a to-do list. Binary Numbers This section introduces the way in which data is represented inside a computer and the form in which it is transmitted across a network. You also learn about the various number systems and logic used with computers. Lab Activity Web Browser Basics In this lab, you learn how to use a web browser to access Internet sites, become familiar with the concept of a URL, and use a search engine to locate informa- tion on the Internet. You access selected websites to learn the definitions of net- working terms and use hyperlinks to jump from the current website to other websites. Lab Activity The Basic PC/Network Troubleshooting Process In this lab, you apply the basic troubleshooting model to simple and common network problems. You also become familiar with the more common hard- ware and software problems. 1102.book Page 18 Tuesday, May 20, 2003 2:53 PM . Windows operating system and use the Control Panel to find out information about the PC hardware. 11 02. book Page 11 Tuesday, May 20 , 20 03 2: 53 PM 12 Chapter 1: Introduction to Networking Network Interface. connection, host name, MAC (Layer 2) address, and network (Layer 3) address. 11 02. book Page 15 Tuesday, May 20 , 20 03 2: 53 PM 16 Chapter 1: Introduction to Networking determine if there is connectivity. not become widely used until the early 19 80s, and the transfer of 11 02. book Page 14 Tuesday, May 20 , 20 03 2: 53 PM Testing Connectivity with Ping 15 files and graphics began to be desirable. The