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fiber optics
The branch of optical technology concerned with the transmission of radiant power
through fibers made of transparent materials such as glass, fused silica, and plastic. (E)
fiber-optic cable
A cable made of ultra-thin glass or silica fibers which can transmit data using pulses of
laser light. Fiber-optic cables have several advantages over copper cables: they have
much less signal loss; they allow information to be transmitted at higher speeds and
over longer distances; they are not affected by external electrical noise; and they are
better for transmissions which require security.
fiber-optic connector
One of several types of devices used to join pairs of optical fibers together.
Fibre Channel
The National Committee for Information Technology Standards standard that defines
an ultrahigh-speed, content-independent, multilevel data transmission interface that
supports multiple protocols simultaneously. Fibre Channel supports connectivity to
millions of devices over copper or fiber-optic physical media and provides the best
characteristics of both networks and channels over diverse topologies.
fibre connection (FICON)
An ESA/390 and zSeries computer peripheral interface. The I/O interface uses
ESA/390 and zSeries FICON protocols (FC-FS and FC-SB-2) over a Fibre Channel
serial interface that configures units attached to a FICON-supported Fibre Channel
communications fabric.
FICON channel
A channel having a Fibre Channel connection (FICON) channel-to-control-unit I/O
interface that uses optical cables as a transmission medium. May operate in either FC
or FCV mode.
file-protect
To prevent the erasure or overwriting of data stored on data cartridges. See also
write-protect switch.
file sync
A sync operation or command used to force data to tape.
For FICON: The command protocol is a tape mark command without a count
■
field.
For Fibre Channel: The command protocol is not an actual synch command. It is a
■
tape mark command that includes a count field. A count equal to zero indicates a
file synch.
firmware
An ordered set of instructions and data stored in a way that is functionally
independent of main storage; for example, microprograms stored in a ROM. (T) See
also microcode.
FL_Port
A special type of fabric port that an arbitrated loop uses to connect N_Ports and NL_
Ports into a fabric, thus making a public loop.
FL_Port
Glossary-5
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