IBM TotalStorage NAS 300, Справочник пользователя

Страница: 189 / 200

electromagnetic compatibility (EMC). The design and test of products to meet legal and corporate specifications
dealing with the emissions and susceptibility to frequencies in the radio spectrum. Electromagnetic compatibility is the
ability of various electronic equipment to operate correctly in the intended electromagnetic environment.
electrostatic discharge (ESD). An undesirable discharge of static electricity that can damage equipment and
degrade electrical circuitry.
EMC. See electromagnetic compatibility .
engine. The unit that contains the processors that respond to requests for data from clients. The operating software
for the IBM TotalStorage appliance resides in the engine.
equivalent paths. A collection of paths to the storage device. The paths have no switchover time penalty when
changing from one path group to another while accessing the storage device.
error. A discrepancy between a computed, observed, or measured value or condition and the true, specified, or
theoretically correct value or condition (A) (I). Contrast with failure .
ESD. See electrostatic discharge .
Ethernet. A standard protocol for a 10-Mbps baseband local area network (LAN) that allows multiple access and
manages contention by using carrier sense multiple access with collision detection (CSMA/CD) as the access method.
Ethernet network. A baseband LAN with a bus topology in which messages are broadcast on a coaxial cable using
a carrier sense multiple access/collision detection (CSMA/CD) transmission method.
expansion slot. In personal-computer systems, one of several receptacles in the rear panel of the system unit into
which a user can install an adapter.
Extended Industry Standard Architecture (EISA). The PC bus standard that extends the AT bus (ISA bus) to 32
bits and provides support for bus master. It was announced in 1988 as a 32-bit alternative to the Micro Channel that
would preserve investment in existing boards. PC and AT cards (ISA cards) can plug into an EISA bus.
F
fabric. A complex network using hubs, switches and gateways. For example, Fibre Channel uses a fabric to connect
devices. A fabric can be as simple as a single cable connecting two devices.
failback. The restoration of an appliance to its initial configuration after detection and repair of a failed network or
component.
failover. (1) The automatic recovery of resources in the event of a network outage, or failure of the hardware or
software. (2) A cluster event in which the primary database server or application server switches to a backup system
due to the failure of the primary server.
Fast Etherchannel (FEC). A proprietary technology developed by Cisco that creates a team of two to four 10/100
Ethernet adapters or ports to increase transmission and reception throughput. Adapter fault tolerance is also supported
by this technology.
feature code. A code used by IBM to process hardware and software orders.
FEC. See Fast Etherchannel .
fiber optic cable. See optical cable .
field-replaceable unit (FRU). An assembly that is replaced in its entirety when any one of its components fails. In
some cases, a FRU may contain other FRUs. Contrast with customer-replaceable unit .
flash memory. A type of non-volatile storage device that must be erased in fixed blocks rather than single bytes.
FRU. See field-replaceable unit .
Glossary of terms and abbreviations
175