180 Glossary
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.
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.
ESM — Embedded server management.
expansion bus — Your system contains an expansion bus that allows the processor to
communicate with controllers for peripherals, such as NICs.