IBM DS8000 manual Extended count key data Eckd, Extent pool, Failback, Failover, Fast write

special symbols with a coded character set of 256 eight-bit codes.

extended count key data (ECKD)

An extension of the count key data (CKD) architecture.

extent A continuous space on a disk that is occupied by or reserved for a particular data set, data space, or file. The unit of increment is a track. See also multiple allegiance and parallel access volumes.

extent pool

A groups of extents. See also extent.

F

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

Pertaining to a cluster recovery from failover following repair. See also failover.

failover

Pertaining to the process of transferring all control to a single cluster when the other cluster in the storage unit fails. See also cluster and failback.

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 See feature code. Note: FC is a common abbreviation for fibre channel in the industry, but the DS8000 customer documentation library reserves FC for feature code.

FC-ALSee Fibre Channel-Arbitrated Loop. FCP See fibre-channel protocol.

FCS See fibre-channel standard.

feature code (FC)

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

A data-transmission architecture based on the ANSI Fibre Channel standard, which supports full-duplex communication. The DS8000 supports data transmission over fiber-optic cable through its fibre-channel adapters. See also fibre-channel protocol and 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.

fibre-channel connection (FICON)

A fibre-channel communications protocol designed for IBM mainframe computers and peripherals.

fibre-channel protocol (FCP)

A protocol used in fibre-channel communications with five layers that 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 (for example, FCP for SCSI command protocols and SBCON for zSeries command protocols). Refer to American National Standards Institute (ANSI) X3.230-199x. See also fibre-channel protocol.

fibre-channel topology

An interconnection topology supported on fibre-channel adapters. See also point-to-point connection, switched fabric, and arbitrated loop.

334IBM TotalStorage DS8000: Messages Reference