Storage System Hardware Owner's Manual

Glossary 171
DDR — Double-data rate. A technology in memory modules that potentially doubles
the output.
device driver — A program that allows the operating system or some other program to
interface correctly with a peripheral. Some device drivers—such as network drivers—
must be loaded from the config.sys file or as memory-resident programs (usually, from
the autoexec.bat file). Others must load when you start the program for which they
were designed.
DHCP — Dynamic Host Configuration Protocol. A method of automatically
assigning an IP address to a client system.
diagnostics — A comprehensive set of tests for your system.
DIMM — Dual in-line memory module. See also memory module.
DIN — Deutsche Industrie Norm.
directory — Directories help keep related files organized on a disk in a hierarchical,
“inverted tree” structure. Each disk has a “root” directory. Additional directories that
branch off the root directory are called subdirectories. Subdirectories may contain
additional directories branching off them.
DMA — Direct memory access. A DMA channel allows certain types of data transfer
between RAM and a device to bypass the processor.
DMI — Desktop Management Interface. DMI enables the management of your
system’s software and hardware by collecting information about the system’s
components, such as the operating system, memory, peripherals, expansion cards, and
asset tag.
DNS — Domain Name System. A method of translating Internet domain names, such
as www.dell.com, into IP addresses, such as 143.166.83.200.
DRAC — Dell Remote access controller.
DRAM — Dynamic random-access memory. A system’s RAM is usually made up
entirely of DRAM chips.
DVD — Digital versatile disc.
ECC — Error checking and correction.
EEPROM — Electronically erasable programmable read-only memory.
EMC — Electromagnetic compatibility.
EMI — Electromagnetic interference.
ERA — Embedded remote access. ERA allows you to perform remote, or "out-of-
band," server management on your network server using a remote access controller.
ESD — Electrostatic discharge.
Book.book Page 171 Monday, September 14, 2009 12:57 PM