HP A7173A PCI-X Dual Channel Ultra320 SCSI Host Bus Adapter Support Guide, August 2007

E
electronically
erasable
programmable
read-only
memory
(EEPROM)
A memory chip typically used to store configuration information. See Non-Volatile Random
Access Memory (NVRAM).
external SCSI
device
A SCSI device installed outside the computer cabinet. External SCSI devices are connected in
a chain using shielded cables.
F
Fast SCSI A standard for SCSI data transfers. It allows a transfer rate of up to 10 MBytes/sec over an 8-bit
SCSI bus, and up to 20 MBytes/sec over a 16-bit SCSI bus.
FCC Federal Communications Commission.
firmware Software that is permanently stored in ROM. In the case of PDC, it can be accessed during boot
time without the aid of an operating or file system.
H
hard disk A rigid disk permanently sealed into a drive cartridge. A hard disk can store very large amounts
of information.
host The computer system in which a SCSI host bus adapter is installed. It uses the SCSI host bus
adapter to transfer information to and from devices attached to the SCSI bus.
host bus adapter A circuit board and/or integrated circuit device that provides a SCSI bus connection to the
computer system.
I
internal SCSI
device
A SCSI device installed inside the computer cabinet. These devices are connected in a chain
using an unshielded ribbon cable.
interrupt request
channel (IRQ)
A path through which a device can get the immediate attention of the computer’s CPU. The
PCI bus assigns an IRQ path for each SCSI host bus adapter.
K
KByte (kilobyte) A measure of computer storage equal to 1024 bytes.
L
logical unit A subdivision, either logical or physical, of a SCSI device. Most devices have only one logical
unit, but up to sixteen are allowed for a 16-bit SCSI bus and eight for an 8-bit SCSI bus.
logical unit
number (LUN)
An encoded three-bit number for the logical unit.
Low Voltage
Differential
A robust design methodology that improves power consumption, data integrity, cable lengths,
and support for multiple devices while providing a migration path for increased I/O
sperformance.
LVD See Low Voltage Differential.
M
main memory The part of a computer’s memory that is directly accessible by the CPU (usually synonymous
with RAM).
mainboard A large circuit board that holds RAM, ROM, the microprocessor, custom integrated circuits,
and other components that make a computer work. It also has expansion slots for host bus
adapters and other plug-in boards.
78 Glossary