The following changes were made in the second printing of the textbook during the summer of 2002 (print number is the lowest number in the line of numbers shown at the bottom of the copyright page—page ii):
Chapter 4, page 153: The first four paragraphs under the heading "Linux" have been replaced with the following two paragraphs:
Linux (pronounced LEN-UKS) is one of the fastest-growing operating systems. Based on the UNIX operating system, it was created by a Finnish programmer named Linus Torvalds, who began developing the operating system as part of a research project. Torvalds designed Linux as an open-source software program, which means that the developer retains ownership but makes the programming code available free to users, who are encouraged to experiment with the software, make improvements, and share the improvements with the entire user community, including the original developer. Open-source software contrasts with another category called proprietary software, which includes the majority of programs in widespread use. Proprietary software programs are owned by a company or an individual and require a fee for using the software.
Like UNIX, Linux was designed mainly for use with servers and large computer systems, including midrange servers and mainframes. However, versions are available for smaller computers such as PCs. Linux can be downloaded via the Internet for free, and numerous utilities are also available. Torvalds now lives in California and continues to devote much of his time to refining his namesake operating system, although he delegates many of the tasks to staff members.
Chapter 6, page 223: In the first sentence of the second paragraph, the phrase "sometimes called dial-up modems" has been deleted. A new sentence has been added to the beginning of the fourth paragraph:
Most personal computers use a type of modem called a dial-up modem, which can dial a telephone number, establish a connection, and close the connection when it is no longer needed.
Chapter 6, page 225: The information under the heading "Twisted-Pair Cable" has been modified to read:
Twisted-pair cable, one of the older types of communications media, was originally developed for telephone networks. Early versions consisted of wires wrapped (twisted) around one another to reduce noise. Today, such cables used with computer networks typically consist of two parallel copper wires, each individually wrapped in plastic and bound together by another plastic casing (see Figure 6-6). The pairs are often bundled in packs of hundreds or thousands, buried in underground electrical conduits (pipes), and run to various locations, such as buildings and rooms, where they can be connected to standard phone jacks.
Twisted-pair cable can be used to connect computers in networks for transmitting data over relatively short distances. Millions of home computer owners use this medium with a modem because the cable is already in place. The advantages of twisted-pair cable are its availability and low price. To ensure more accurate transmissions over long distances, repeater stations may be positioned along the way to refresh (strengthen) the communication signals.
Chapter 6, page 227: In the first heading, "Internet Services Digital Network (ISDN) Lines," the word "Internet" has been changed to "Integrated."
Chapter 6, page 233: The opening sentence under the heading "Client/Server Architecture" has been revised into two sentences, as follows:
In client/server architecture (see Figure 6-13), networked personal computers, workstations, or terminals (clients) can send requests to, and receive services from, another typically more powerful computer called a server. The server can store programs, files, and data that are available to authorized users.
Chapter 6, page 242: The second sentence under the heading "Ring Topologies" has been revised as follows:
A type of ring technology called token ring uses a single electronic signal, or token, to pass information from the source computer to the destination.
Chapter 6, page 247: In the table called "Communications Protocols," the last item in the left column, "File Transfer Protocol (FTP)," has been placed in a light green band to show that it is a separate item.
In the final sentence of the paragraph immediately below Table 6-2, the clause "until all manufacturers adopt OSI" has been changed to "unless the OSI model becomes universally accepted by users."
Chapter 7, page 306: In question 5, the "d" answer has been changed from "downloads" to "packets."
Chapter 10, page 433: In question 9, the "d" answer has been changed from "SQL" to "HTTP."
Chapter 12, page 495: In Table 12-1, the Visual Basic language item is identified in the "Compiled" column as "Yes" rather than "No."
Chapter 13, page 529: In the paragraph under the heading "Creating the Content of the Work," the name of the digital format "Motion Picture Experts Group (MPEG)" has been changed to "Moving Picture Experts Group (MPEG)."