Specifications
the Model F10, including the ability to support a
separate expansion enclosure.
fabric. In fibre-channel technology, a routing structure,
such as a switch, receives addressed information and
routes to the appropriate destination. A fabric can
consist of more than one switch. When multiple
fibre-channel switches are interconnected, they are said
to be cascaded.
failback. Cluster recovery from failover following
repair. See failover.
failover. On the ESS, the process of transferring all
control of a storage facility to a single cluster when the
other cluster in the storage facility fails.
fast write. A write operation at cache speed that does
not require immediate transfer of data to a disk drive.
The subsystem writes the data directly to cache, to
nonvolatile storage, or to both. The data is then
available for destaging. A fast-write operation reduces
the time an application must wait for the I/O operation to
complete.
FBA. See fixed-block architecture.
FC-AL. See Fibre Channel-Arbitrated Loop.
FCP. See fibre-channel protocol.
FCS. See fibre-channel standard.
feature code. A code that identifies a particular
orderable option and that is used by service personnel
to process hardware and software orders. Individual
optional features are each identified by a unique feature
code.
fibre channel (FC). A data-transmission architecture
based on the ANSI fibre-channel standard, which
supports full-duplex communication. The ESS supports
data transmission over fiber-optic cable through its
fibre-channel adapters. See fibre-channel protocoland
fibre-channel standard.
Fibre Channel-Arbitrated Loop (FC-AL). An
implementation of the fibre-channel standard that uses a
ring topology for the communication fabric. Refer to
American National Standards Institute (ANSI)
X3T11/93-275. In this topology, two or more
fibre-channel end points are interconnected through a
looped interface. The ESS supports this topology.
fibre-channel connection (FICON). A fibre-channel
communications protocol designed for IBM mainframe
computers and peripherals.
fibre-channel protocol (FCP). For fibre-channel
communication, the protocol has five layers. The layers
define how fibre-channel ports interact through their
physical links to communicate with other ports.
fibre-channel standard (FCS). An ANSI standard for
a computer peripheral interface. The I/O interface
defines a protocol for communication over a serial
interface that configures attached units to a
communication fabric. The protocol has two layers. The
IP layer defines basic interconnection protocols. The
upper layer supports one or more logical protocols.
Refer to American National Standards Institute (ANSI)
X3.230-199x.
FICON. See fibre-channel connection.
FiconNet. In ESS Specialist, the label on a
pseudo-host icon representing a host connection that
uses the FICON protocol and that is not completely
defined on the ESS. See pseudo-host and access-any
mode.
field replaceable unit (FRU). An assembly that is
replaced in its entirety when any one of its components
fails. In some cases, a field replaceable unit may
contain other field replaceable units.
FIFO. See first-in-first-out.
firewall. A protection against unauthorized connection
to a computer or a data storage system. The protection
is usually in the form of software on a gateway server
that grants access to users who meet authorization
criteria.
first-in-first-out (FIFO). A queuing technique in which
the next item to be retrieved is the item that has been in
the queue for the longest time. (A)
fixed-block architecture (FBA). An architecture for
logical devices that specifies the format of and access
mechanisms for the logical data units on the device.
The logical data unit is a block. All blocks on the device
are the same size (fixed size). The subsystem can
access them independently.
fixed-block device. An architecture for logical devices
that specifies the format of the logical data units on the
device. The logical data unit is a block. All blocks on the
device are the same size (fixed size); the subsystem
can access them independently. This is the required
format of the logical data units for host systems that
attach with a Small Computer System Interface (SCSI)
or fibre-channel interface. See fibre-channel, Small
Computer System Interface and SCSI-FCP.
FlashCopy. An optional feature for the ESS that can
make an instant copy of data, that is, a point-in-time
copy of a volume.
FRU. See field replaceable unit.
full duplex. See duplex.
G
GB. See gigabyte.
Glossary 191
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