The speed at which a computer performs basic operations, usually given in MegaHertz (millions of cycles per second). The clock speed of a computer is determined by the frequency of vibration of a quartz crystal which sends pulses to the CPU. The clock speed of a computer is determined by the frequency of vibration of a quartz crystal which sends pulses to the CPU. Clock speed can be misleading when used to compare the performance of different types of computers; benchmarks try to take other variables into account.

CD-ReWritable drive. A CD-ROM drive that can write, erase, and rewrite to a CD-ROM. CD-RW is considered by many to be the perfect bridge from CD to DVD technology because of its backward and forward compatibility with existing CD and future DVD platforms.

Accelerated Graphics Port. A bus specification from Intel that gives graphics cards faster access to main memory than the PCI bus, thus greatly speeding up graphics display and texture rendering, especially virtual reality and 3D rendering and display. AGP allows efficient use of frame buffer memory, thereby helping 2D graphics performance as well. The coherent memory management design allows scattered data in system memory to be read in rapid bursts. The PCI graphics accelerator bus has a data transfer rate of up to 133 MBps. Because it is directly on the motherboard's chipset and has a direct pipeline connection to the computer's main memory, AGP is much faster. AGP is available in two speeds: 1X transfers data at a rate of 264 MBps; 2X transfers data at 528 MBps. The AGP 4X, coming in 1999, will double the bandwidth peak again to 1 GBps.

A cookie is a set of data that a Web site server gives to a browser the first time the user visits the site, that is updated with each return visit. The remote server saves the information the cookie contains about the user and the user's browser does the same, as a text file stored in the Netscape or Explorer system folder. Not all browsers support cookies. Cookies store information such as user name and password and what parts of the site were visited; this information can be updated with each visit. The browser only shares each cookie with the server that originated it; other servers can only read their own cookies. Netscape can be set up to alert the user when a cookie is being sent so the user can accept it or not, by means of the Network Preferences window. There are also downloadable applications that eat cookies such as Cookie Killers, Cookie Monster (Mac), and Kill Cookie Batch File (PC).

1. Device drivers are programs that extend the operating system to support a device such as a disk or tape drive; or programs that enable an application to use a device such as a printer driver. Hardware devices such as sound cards, printers, scanners, and CD-ROM drives must each have the proper driver installed in order to run. 2. A line driver is a circuit that is used to increase the signal current in order to send data over long distances or to many circuits. It must be at each end of the transmission line.

An open specification from Intel for a motherboard that is a further evolution of the Baby AT, giving more space for expansion slots and Input/Output. The motherboard is rotated 90 degrees in its chassis. The ATX supports multimedia and USB (Universal Serial Bus). In this design, the power supply blows air over the processor chip instead of pulling air through the chassis.

If a computer has 32-bit addressing, it means that each address in memory can have 32 numbers. Since each number could be a 1 or a 0, that means that 2^32 (four billion) addresses are available. The computer could theoretically address up to 4 gigabytes of memory; however, many computers with 32-bit addressing have far less than 4 gigabytes of memory.

Typewritten pictures of facial expressions, used in e-mail and when communicating on the Internet, to indicate emotion. They are also called smileys :-) . See the emoticon list in this dictionary for examples.

A channel where information is stored on magnetic or optical media. Tracks come in three forms: 1. The concentric rings on a floppy disk or hard disk. Tracks are recorded onto a floppy disk during formatting; a high-density floppy has 160 tracks. Disk storage is organized in tracks and sectors, which are pie-shaped slices. A combination of two or more sectors on a single track makes a cluster or block, the minimum unit used to store information. 2. On CDs and videodiscs, tracks are in spiral form. 3. On magnetic tape, tracks run parallel to the length of the tape, or diagonally for helical scan tracks.

The development of computers began in the late 1940s and early 1950s with huge mainframes that used vacuum tube technology. The second generation of computers were built with discrete transistors, from the mid-1950s through the mid-1960s. Third-generation computers were built using integrated circuits after the mid-1960s; during this time period, minicomputers were developed. The fourth generation of computers are the microcomputers which use large-scale integration or very large-scale integration. The fifth generation of computers, beginning in the late 1990s, is expected to greatly expand the use of artificial intelligence. See also first generation computer, second generation computer, third generation computer, fourth generation computer, fifth generation computer.