148 Glossarycontroller—A device that controls the transfer of data from acomputer to a peripheral device and vice versa. Forexample, disk drives, monitors, keyboards, and printers allrequire controllers.CPU—SeeCentral Processing Unit (CPU).CPU cache—A section of very fast memory residing betweenthe CPU and the computer’s main memory that temporarilystores data and instructions the CPU will need to executecommands and programs. See alsocache,L1 cache,L2cache.cursor—An on-screen symbol (usually a flashing vertical line)that indicates the position where characters will appearwhen you enter data.D Desktop—Offers the traditional look and feel of the Windows®desktop found in Windows® 7 and earlier releases of theWindows® operating system.default—The setting selected by a program when the user doesnot specify an alternative setting.device—A component attached to the computer. Devices maybe external (outside the computer’s case) or internal (insidethe computer’s case). Printers, disk drives, and modems areexamples of devices.device driver—A program (called a “driver”) that permits acomputer to communicate with a device.dialog box—An on-screen window displayed by the operatingsystem or a program giving a direction or requesting inputfrom the user.Direct Current (DC)—The type of power usually supplied bybatteries. DC flows in one direction. CompareAlternatingCurrent (AC).Direct Memory Access (DMA)—A dedicated channel,bypassing the CPU, that enables direct data transferbetween memory and a device.directory—Seefolder.disable—To turn a computer option off. See alsoenable.
