IBM DS5020 204

StandardArchitecture (ISA) system bus on the IBM PC

ATcomputer. Equivalent to integrated drive electronics

(IDE).

auto-volume transfer/auto-disk transfer (AVT/ADT).

Afunction that provides automatic failover in case of

controller failure on a storage subsystem.

AVT/ADT. Seeauto-volume transfer/auto-disk transfer.

AWT. See Abstract Windowing Toolkit.

basic input/output system (BIOS). The personal

computer code that controls basic hardware operations,

such as interactions with diskette drives, hard disk

drives, and the keyboard.

BIOS. See basic input/output system.

BOOTP. Seebootstrap protocol.

bootstrap protocol (BOOTP). In Transmission Control

Protocol/Internet Protocol (TCP/IP) networking, an

alternative protocol by which a diskless machine can

obtain its Internet Protocol (IP) address and such

configuration information as IP addresses of various

servers from a BOOTP server.

bridge. Astorage area network (SAN) device that

provides physical and transport conversion, such as

Fibre Channel to small computer system interface

(SCSI) bridge.

bridge group. Abridge and the collection of devices

connected to it.

broadcast. The simultaneous transmission of data to

more than one destination.

cathode ray tube (CRT). Adisplay device in which

controlled electron beams are used to display

alphanumeric or graphical data on an

electroluminescent screen.

client. Acomputer system or process that requests a

service of another computer system or process that is

typically referred to as a server.Multiple clients can

share access to a common server.

command. Astatement used to initiate an action or

start a service.A command consists of the command

name abbreviation, and its parameters and flags if

applicable.A command can be issued by typing it on a

command line or selecting it from a menu.

community string. The name of a community

contained in each Simple Network Management

Protocol (SNMP) message.

concurrent download. Amethod of downloading and

installing firmware that does not require the user to stop

I/O to the controllers during the process.

CRC. See cyclic redundancy check.

CRT. Seecathode ray tube.

CRU. See customer replaceable unit.

customer replaceable unit (CRU). An assembly or

part that a customer can replace in its entirety when any

of its components fail. Contrast with field replaceable

unit (FRU).

cyclic redundancy check (CRC). (1)A redundancy

check in which the check key is generated by a cyclic

algorithm. (2)An error detection technique performed at

both the sending and receiving stations.

dac. See disk array controller.

dar. Seedisk array router.

DASD. See direct access storage device.

data striping. See striping.

default host group. Alogical collection of discovered

host ports, defined host computers, and defined host

groups in the storage-partition topology that fulfill the

following requirements:

vAre not involved in specific logical drive-to-LUN

mappings

vShare access to logical drives with default logical

drive-to-LUN mappings

device type. Identifier used to place devices in the

physical map, such as the switch, hub, or storage.

DHCP. SeeDynamic Host Configuration Protocol.

direct access storage device (DASD). Adevice in

which access time is effectively independent of the

location of the data. Information is entered and retrieved

without reference to previously accessed data. (For

example, a disk drive is a DASD, in contrast with a tape

drive, which stores data as a linear sequence.) DASDs

include both fixed and removable storage devices.

direct memory access (DMA). The transfer of data

between memory and an input/output (I/O) device

without processor intervention.

disk array controller (dac). Adisk array controller

device that represents the two controllers of an array.