Service manual

Glossary-3
DAC Digital-to-analog converter. A mechanical or electronic device used to convert
discrete digital numbers to continuous analog signals.
data bus A set of hardware lines (wires) used for data transfer among the components of
a computer system.
DBZ Double-buffer plus Z.
DCE Data communication equipment. A type of hardware, such as a modem, that is
responsible for encoding a digital signal for delivery to a compatible DCE
connected by a data link.
default An alternative value, attribute, or option assumed when none has been
specified.
diagnostics The diagnostic firmware contained in the boot PROM. These diagnostics
include the Power-On Self Test (POST) and on-board diagnostics.
DMA Direct memory access. The transfer of data directly into memory without
supervision of the processor. The data is passed on the bus directly between
the memory and another device.
dpi Dots per inch.
DPS Data path scheduler. Controls all data flow coordinating the activity of the
BMX chips.
DRAM Dynamic random-access memory. A read/write dynamic memory in which the
data can be read or written in approximately the same amount of time for any
memory location.
DSIMM DRAM single in-line memory module. A small printed circuit card that
contains dynamic random access memory (DRAM) chips.
DTAG Dual tag or data tag.
DTE Data terminal equipment. That part of a data station that serves as a data
source, data sink, or both, and provides for the data communication control
function according to protocols.
ECC Error checking and correction. The detection, in the processing unit, and
correction of all single-bit errors, plus the detection of double-bit and some
multiple-bit errors.
EEPROM Electrically erasable PROM. A non-volatile PROM that may be written to as
well as read from. An EEPROM is used to hold information about the current
system configuration, alternate boot paths, and so on.
EMI Electromagnetic interference. An electromagnetic phenomena which, either
directly or indirectly, can contribute to a degradation in performance of an
electronic system.
ESD Electrostatic discharge.