Glossary 131
device driver—A program (called a “driver”) that permits a
computer to communicate with a device.
dialog box—An on-screen window displayed by the
operating system or an application giving a direction or
requesting input from the user.
Direct Current (DC)—The type of power usually supplied
by batteries. DC flows in one direction. Compare
Alternating Current (AC).
Direct Memory Access (DMA)—A dedicated channel,
bypassing the CPU, that enables direct data transfer
between memory and a device.
directory—See
folder.
disable—To turn a computer option off. See also
enable.
disc—A round, flat piece of material, designed to be read
from and written to by optical (laser) technology, and
used in the production of optical discs, such as CDs and
DVDs. Compare
disk.
disk—A round, flat piece of material that can be
magnetically influenced to hold information in digital
form, and used in the production of magnetic disks,
such as hard disks. Compare
disc. See also
hard disk.
disk drive—The device that reads and writes information
and applications on external media or hard disk. It
rotates the disk at high speed past one or more
read/write head s.
document—Any file created with an application and, if
saved to disk, given a name by which it can be retrieved.
See also
file
.
double-click—To press and release the pointing device’s
primary button rapidly twice without moving the pointing
device. In the Windows® operating system, this refers to
the pointing device’s left button, unless otherwise
stated.