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dynamic random access memory (DRAM). A
storage in which the cells require repetitive application
of control signals to retain stored data.
E_Port. An expansion port that connects the switches
for two fabrics (also used for McData ES-1000 B ports).
ECC. See error correction coding.
EEPROM. See Electrically Erasable Programmable
Read-Only Memory.
EGA. See enhanced graphics adapter.
electrically eErasable programmable read-only
memory (EEPROM). A type of non-volatile storage
device that can be erased with an electrical signal.
Writing to EEPROM takes much longer than reading. It
also can only be reprogrammed a limited number of
times before it wears out. Therefore, it is appropriate for
storing small amounts of data that are changed
infrequently.
electrostatic discharge (ESD). The flow of current
that results when objects that have a static charge
come into close enough proximity to discharge.
enhanced graphics adapter (EGA). An IBM video
display standard that provides text and graphics with a
resolution of 640 x 350 pixels of 16 colors. It emulates
the Color/Graphics Adapter (CGA) and the Monochrome
Display Adapter (MDA) and was superseded by the
Video Graphics Display (VGA).
enhanced small disk interface (ESDI). A hard disk
controller standard that allows disks to communicate
with computers at high speeds. ESDI drives typically
transfer data at about 10 megabits per second, although
they are capable of doubling that speed.
error correction coding (ECC). A method for
encoding data so that transmission errors can be
detected and corrected by examination of the data on
the receiving end. Most ECCs are characterized by the
maximum number of errors they can detect and correct.
error detection coding. A method for encoding data
so that errors that occur during storage or transmission
can be detected. Most error detection codes are
characterized by the maximum number of errors they
can detect. The simplest form of error detection is by
using a single added parity bit or a cyclic redundancy
check. Adding multiple parity bits can detect not only
that an error has occurred, but also which bits have
been inverted, thereby indicating which bits should be
re-inverted to restore the original data.
ESD. See electrostatic discharge.
ESDI. See enhanced small disk interface.
eXtended graphics array (XGA). An IBM advanced
standard for graphics controller and display mode
design introduced in 1990. XGA, used mostly on
workstation-level systems, supports a resolution of 1024
x 768 pixels with a palette of 256 colors, or 640 x 480
with high color (16 bits per pixel). XGA-2 added 1024 x
768 support for high color and higher refresh rates,
improved performance, and supports 1360 x 1024 in 16
colors.
F_Port. A port that supports an N_Port on a Fibre
Channel switch.
fabric group. A collection of interconnected SAN
devices discovered by the SANavigator tool and
displayed with a blue background on the Physical and
Data Path Maps.
Fibre Channel. A bi-directional, full-duplex,
point-to-point, serial data channel structured for high
performance capability. Physically, Fibre Channel
interconnects devices, such as host systems and
servers, FC hubs and disk arrays, through ports, called
N_Ports, in one of three topologies: a point-to-point link,
an arbitrated loop, or a cross point switched network,
which is called a fabric. FC can interconnect two
devices in a point-to-point topology, from two to 126
devices in an arbitrated loop. FC is a generalized
transport mechanism that can transport any existing
protocol, such as SCSI, in FC frames.
Fibre Channel Protocol for SCSI (FCP). A high-level
Fibre Channel mapping layer (FC-4) that uses
lower-level Fibre Channel (FC-PH) services to transmit
SCSI command, data, and status information between a
SCSI initiator and a SCSI target across the FC link by
using FC frame and sequence formats.
field replaceable unit (FRU). An assembly that is
replaced in its entirety when any one of its components
fails. In some cases, a FRU might contain other field
replaceable units.
FRU. See field replaceable unit.
general purpose interface bus (GPIB). An 8-bit
parallel bus developed for the exchange of information
between computers and industrial automation
equipment.
GPIB. See general purpose interface bus..
graphical user interface (GUI). A type of computer
interface that presents a visual metaphor of a real-world
scene, often of a desktop, by combining high-resolution
graphics, pointing devices, menu bars and other menus,
overlapping windows, icons, and the object-action
relationship.
GUI. See graphical user interface.
HBA. See host bus adapter.
hdisk. An AIX term representing a logical unit number
(LUN) on an array.
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Glossary
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