Barrons Publishing Dictionary of Computer and Internet Terms 10th

One important measure of the capability of a microprocessor is the number of bits that each internal register can contain. For example, the classic Z80 microprocessor had 8-bit registers. The Intel 8088, used in the original IBM PC, had 16-bit registers but only an 8-bit bus, leading to some confusion as to whether it should really have been called a 16bit processor. Newer microprocessors have 32 or 64 bits per register. In general, a processor with a greater number of bits per instruction can process data more quickly (although there are other factors to consider that also determine a computer’s speed). See also MICROPROCESSOR.

The number of colors that can be displayed is sometimes given by listing the number of bits used to represent a color. For example, a 24bit color system uses 8 bits for red, 8 for green, and 8 for blue, so it can display 28 = 256 different levels of each of the three primary colors, or 224 = 16,777,216 different mixtures of colors. See COLOR.

The term bit is also used to indicate the quality of digitized sound, as in 8 bit or 16 bit. See SAMPLING RATE.

bit bucket (slang) a place where data is lost. For example, under UNIX, the filename /dev/null can be used as a bit bucket; anything written to it will be ignored, but the program will think it is successfully writing to a file.

bit depth in graphics, the number of bits that are used to record the intensity and color of each pixel. For example, 1-bit graphics can distinguish only black and white; 8-bit graphics can distinguish 256 shades of gray or 256 colors; and 24-bit graphics can distinguish more than 16 million colors. Sometimes bit depth denotes the number of levels of each color; for example, an image in which each pixel has 8 bits each for red, green, and blue might be called either a 24-bit image or an 8-bit RGB image.

bitblt (bit-block transfer, pronounced “bitblit”) the rapid copying of a block of memory or a portion of an image from one place to another.

Compare BLIT.

bitlocker a security feature of Vista that encrypts data on a hard drive, using an encryption key contained in a separate microchip in the computer, or provided on a flash drive.

bitmap a graphical image represented as an array of brightness values. For example, if 0 represents white and 1 represents black, then

00000000

01111110

01000010

01000010

01111110

00000000

is a bitmap of a black rectangle on a white background. Each point for which there is a value is called a PIXEL. See also DIGITAL IMAGE PROCESSING.

Bitmaps can be imported into other application programs such as word processors and page layout programs, but you will not be able to edit bitmaps in those environments. You must use a PAINT PROGRAM to change bitmaps. Contrast VECTOR GRAPHICS. See also DRAW PROGRAM;

PAINT PROGRAM.

bitmap graphics a method of displaying pictures on a computer. The picture is treated as a large array of pixels (see PIXEL), each of which is stored in a specific memory location. The picture is drawn by specifying the color of each pixel. Contrast VECTOR GRAPHICS. See also BITMAP; DRAW PROGRAM; PAINT PROGRAM.

bitness (slang) the property of using a specific number of bits. For example, a single-precision integer and a double-precision integer differ in bitness.

BITNET a wide-area network linking university computer centers all over the world. It originated in the northeastern United States in the early 1980s and was later combined with the Internet. Its most common use was to transmit electronic mail among scholars who were working together.

BitTorrent a peer-to-peer file sharing system that reduces dependency on the original host (or the SEED) by having everyone who downloads the file also offer it for anonymous upload to others. The more people who download the file (and therefore host the pieces they already have), the faster the file is downloaded. This format is especially useful for large files such as rich media (movies, music, etc.). See www.bittorrent.com.

.biz a suffix indicating that a web or e-mail address belongs to a business (in any country). Contrast .COM. See also ICANN; TLD.

black hat someone who attempts to break into computers maliciously; a villain (like the characters in old Western movies who wore black hats).

Contrast WHITE HAT.

BlackBerry a wireless device produced by Research In Motion, Inc., which is a combination cellular telephone, PDA, and web browser. Web address: www.blackberry.com. See also PDA.

Blackberry thumb an informal name for painful repetitive stress injuries caused by excessive typing on small keyboards like the ones on Blackberries or cellular phones. See CARPAL TUNNEL SYNDROME.

Blackcomb Microsoft’s code name for the version of Windows that will succeed Windows Vista. Blackcomb is better known as Windows 7.

blacklist a list of senders or sites from which messages will not be accepted. Synonyms: IGNORE LIST; KILL FILE.

blend

1.a drawing program command that computes the intermediate shapes between two selected objects. You would use the blend command to make the smooth highlights on a rendering of a three-dimensional object.

In many ways, the blend command is like the morphing special effects we see on television commercials. You could make the letter C turn into a cat, for example. However, blend has practical applications as well as the playful ones. You can use it to create equally spaced objects, such as lines for a business form. Align two identical objects, and then set the intermediate blend steps to the desired number.

2.a paint program filter that smooths colors and removes texture over a selected area.

3.A piece of digital art where several images have been combined seamlessly into a visually interesting whole. Figures and objects are often layered so that it takes several seconds to identify what you are seeing.

FIGURE 33. Blend (in a draw program)

blind copies see BCC.

blit block image transfer, the rapid copying of a portion of an image (or, sometimes, any type of memory contents) from one place to another. Compare BITBLT.

blittable capable of being copied rapidly by BLIT.

bloatware (slang) bloated software; inefficient, slow software that requires unreasonable amounts of disk space, memory, or CPU speed. Too many added features can make bloatware difficult to use (see CREEPING FEATURISM) and prone to crashes. Many critics claim that much modern software is designed to sell computers larger and faster than are actually needed to do the computations efficiently.

block move the operation of moving a section of a file from one place to another within the file. See EDITOR.

block protect to mark a block of text so that it will not be split across pages when printed out. This is useful to prevent a table or formula from being broken up.

blog a “web log”; a type of personal column posted on the Internet. Most blogs consist of small, plentiful entries. Some blogs are like an individ-

ual’s diary while others have a focused topic, such as recipes or political news.

Blogger a web site (www.blogger.com) providing one of the most popular and oldest web log services. Anyone can maintain a BLOG there and update it from any computer with an Internet connection. Blogger has been owned by GOOGLE since 2003. Compare LIVEJOURNAL; WORDPRESS;

XANGA.

blogosphere The world of BLOGs; the very loosely-knit community of blog writers and their audiences. The blogosphere provides important forums for political discussion and news reporting separate from the established news media.

Blu-Ray disc an optical disc similar to a DVD and the same size, but read and written with a blue or violet laser, whose shorter wavelength makes a higher data density possible. Blu-Ray discs can hold 25 GB (single layer) or 50 GB (double layer). Contrast HD DVD.

Blue Screen of Death (slang) (sometimes written BSOD) in Windows, a serious error message displayed in white type on a blue screen, without any use of windows or graphics (see Figure 34). It usually means that the entire operating system has become inoperative. The memory addresses and filenames it displays are sometimes explained on www.microsoft.com, but they are usually meaningful to only the authors of Windows.

After experiencing a “Blue Screen of Death,” one should always restart the computer in order to load a fresh copy of the

FIGURE 34. Blue Screen of Death

operating system into memory. Windows Vista usually reboots after a serious error of this type, often bypassing the blue screen.

Bluetooth a standard for wireless networking of relatively slow devices in the same room; for details see www.bluetooth.org. The name alludes to a medieval Danish king. Contrast 802.11.

blur a paint program filter that throws the image slightly out of focus. Blur can be repeated until the desired effect is achieved. See also MOTION BLUR.

FIGURE 35. Blur filter

.bmp the filename extension for files in Microsoft Windows that contain bitmap representations of images. See BITMAP.

BNC connector a push-and-twist connector (see Figure 36) used to join coaxial cables in thinwire Ethernet networks and in some types of video equipment. See 10BASE-2; COAXIAL CABLE; ETHERNET. Contrast RCA PLUG.

FIGURE 36. BNC connectors

board

1.a printed circuit board for a computer, the MOTHERBOARD, or an addon board, sometimes also called a card. Most computers contain expansion slots where you can add additional boards to enhance the capabilities of the machine.

2.a bulletin board system (BBS) or similar discussion forum. See BBS.

boat anchor (slang) obsolete, useless machine.

BODY tag used in HTML to indicate the main part of the material for a web page, as opposed to the HEAD. For an example see HTML.

BOF (birds of a feather) an informal meeting of a group of computer professionals with an interest in common, held as part of a larger convention.

bogus (slang. obsolescent) fake, incorrect, or useless. (In computer slang, this word covers a much wider range of meanings than in ordinary English; it can be applied to almost anything that is defective in any way.)

bold a type style that appears heavier and darker than normal type. The entry terms in this dictionary are set in bold type. See WEIGHT.

bomb (slang) to fail spectacularly (either computer programs or human performers); to CRASH. When a program bombs on a Macintosh, an alert box containing a picture of a bomb appears—the computer must be restarted and all changes made since the last “Save” will be lost.

Contrast FREEZE UP; HANG.

bookmark

1.a remembered position in a file that is being edited. Some editors let the user set bookmarks in order to return quickly to specific points in the file.

2.a remembered address on the WORLD WIDE WEB. Web browsers normally let the user record the addresses of web pages in order to go directly to them in the future without having to type the address.

3.a placeholder that allows one to return to a specific point in a multimedia presentation.

Boole, George (1815–1864) the mathematician who discovered that logical reasoning can be represented in terms of mathematical formulas (BOOLEAN ALGEBRA). Boole’s work is the basis of modern digital computing.

Boolean algebra the study of operations carried out on variables that can have only two values: 1 (true) and 0 (false). Boolean algebra was developed by George Boole in the 1850s; it was useful originally in applications of the theory of logic and has become tremendously important in that area since the development of the computer.

Boolean query a query formed by joining simpler queries with and, or, and not. For example: “Find all books with author ‘Downing’ and subject ‘Computers’ and not published before 1987.” See also

SEARCH; SEARCH ENGINE.

Boolean variable a variable in a computer program that can have one of two possible values: true or false. See BOOLEAN ALGEBRA.

Boolean variables are useful when the results of a comparison must be saved for some time after the comparison is done. Also, they can be operated on repeatedly to change their values. For example, the following Java program segment reads numbers in an n-element array called a (which has already been defined) and reports whether a number over 100 was encountered; the Boolean variable is used somewhat as an integer would be used to keep a running total.

boolean b=false;

for (int i=0; i<=n-1; i++)

{

b = (b | (a[i]>100)); /* vertical line means OR */

}

System.out.println(”Was there a number over 100?”); if (b)

{

System.out.println(”There was a number over 100.”);

}

FIGURE 37. Boolean variable in Java

boot to start up a computer. The term boot (earlier bootstrap) derives from the idea that the computer has to “pull itself up by the bootstraps,” that is, load into memory a small program that enables it to load larger programs.

The operation of booting a computer that has been completely shut down is known as a dead start, cold start, or cold boot. A warm start or warm boot is a restarting operation in which some of the needed instructions are already in memory.

boot disk a disk, diskette, or CD that can be used to BOOT (start up) a computer.

boot image see IMAGE (definition 2).

Borland International (briefly renamed Inprise Corporation in the late 1990s) a manufacturer of microcomputer software, founded by Philippe Kahn and headquartered in Scotts Valley, California. Its first products were Turbo Pascal, an extremely popular Pascal compiler released in 1984 (see TURBO PASCAL), and Sidekick, a set of IBM PC utilities that are always resident in RAM and can be called up at any time, even in the middle of another task. Later products include compilers for C and C++, the spreadsheet program Quattro, the database program Paradox, and, most recently, Delphi, Kylix, and Java development tools. Web address: www.borland.com.

boron chemical element (atomic number 5) added to silicon to create a P-type SEMICONDUCTOR.

bot (slang) see ROBOT (definition 2).

bottleneck the part of a computer system that slows down its performance, such as a slow disk drive, slow modem, or overloaded network. Finding and remedying bottlenecks is much more worthwhile than simply speeding up parts of the computer that are already fast.

The Von Neumann bottleneck is a limit on computer speed resulting from the fact that the program and the data reside in the same memory. Thus, at any moment the CPU can be receiving a program instruction or

brittle working correctly but easily disrupted by slight changes in conditions; the opposite of ROBUST.

broadband covering a wide range of frequencies; permitting fast data transfer. In this sense, ADSL lines, T1 lines, and all kinds of Internet connections that are appreciably faster than a modem are often described as broadband.

In a narrower sense, broadband denotes systems of modulating many signals onto different high-frequency carriers so that they can share the same cable. Cable television is a simple example; many video signals are delivered at once, on different frequencies. Broadband Ethernet allows many networks, or a network and other types of signals, to coexist on the same cable by using different high-frequency carriers. Contrast BASEBAND.

broadcast flag a code embedded in a DIGITAL TELEVISION broadcast that is intended to prevent copying or recording by the recipient. In the United States, the FCC issued a rule requiring television receivers (including video recorders and computers) to obey the broadcast flag. This rule was overturned by the U.S. Court of Appeals in 2005 (American Library Association, et. al. v. Federal Communications Commission). The court ruled that the FCC did not have the authority to regulate the use of electronic devices when they were not receiving a broadcast signal (such as when they were playing back a recording). However, Congress could require the use of the broadcast flag by legislation. The issue is a matter of ongoing dispute.

broken hyperlink a link in a web page that points to a document that is no longer at that address. See also DEAD LINK.

broken pipe a communication failure between two programs that are running concurrently. Typically, a broken pipe occurs when a network connection is lost or one of the programs terminates while the other is still trying to communicate with it. See PIPE (definition 1).

brownout an extended period of insufficient power-line voltage. It can damage computer equipment. See POWER LINE PROTECTION.

browse

1.to explore the contents of the World Wide Web or, more generally, the Internet. See BROWSER.

2.to explore the contents of a disk drive or a computer network.

browse master in Windows, the computer on the local area network that tells the other computers what shared resources are available. The browse master is chosen automatically from the computers that are on the network at a particular time.

browser a computer program that enables the user to read HYPERTEXT in files or on the WORLD WIDE WEB (Figure 41). Popular World Wide Web browsers include Firefox and Microsoft Internet Explorer. See WORLD WIDE WEB; HTML; VRML; FIREFOX; INTERNET EXPLORER; OPERA.