Dell PowerEdge R900 - Manual (Page 175)

Glossary 175
H
— Hexadecimal. A base-16 numbering system, often used in programming to
identify addresses in the system’s RAM and I/O memory addresses for devices. In text,
hexadecimal numbers are often followed by h.
H E A D L E S S S YS T E M
— A system or device that functions without having a keyboard,
mouse, or monitor attached. Normally, headless systems are managed over a network
using an Internet browser.
H O S T A D A P T E R
— A host adapter implements communication between the system’s
bus and the controller for a peripheral device. (Hard-drive controller subsystems
include integrated host adapter circuitry.) To add a SCSI expansion bus to your
system, you must install or connect the appropriate host adapter.
H
Z
— Hertz.
I/O — Input/output. A keyboard is an input device, and a monitor is an output
device. In general, I/O activity can be differentiated from computational activity.
ID — Identification.
IDE — Integrated drive electronics. A standard interface between the system board
and storage devices.
I N T E G R A T E D M I R R O RI N G
— Provides simultaneous physical mirroring of two drives.
Integrated mirroring functionality is provided by the system’s hardware. See also
mirroring.
I N T E RN A L P RO C E S SO R C A C H E
— An instruction and data cache built into the
processor.
IP — Internet Protocol.
IPX — Internet package exchange.
IRQ — Interrupt request. A signal that data is about to be sent to or received by a
peripheral device travels by an IRQ line to the processor. Each peripheral connection
must be assigned an IRQ number. Two devices can share the same IRQ assignment,
but you cannot operate both devices simultaneously.
J U M PE R
— Small blocks on a circuit board with two or more pins emerging from
them. Plastic plugs containing a wire fit down over the pins. The wire connects the
pins and creates a circuit, providing a simple and reversible method of changing the
circuitry in a board.
K — Kilo-; 1000.
K
B
— Kilobit(s); 1024 bits.