IBM 3590 - Manual (Page 155)

error-recovery procedures (ERP). (1) Procedures
designed to help isolate and, where possible, to
recover from errors in equipment. The
procedures are often used in conjunction with
programs that record the statistics of machine
malfunctions. (2) Error-recovery procedures
performed by the subsystem.
explicitly activated. A process in which the
attributes of an identifier are specified. Contrast
with implicitly activated.
extended contingent allegiance. (1) A condition
caused by a permanent buffered-write error in
which the drive responds only to the channel
path group from which the write command was
received. The extended contingent allegiance
continues until a controlling computer in the
channel path group retrieves the unwritten data
from the buffer or issues a tape motion
command. (2) A condition generated by an
initiate recovery message to assist in extended
error recovery procedures in multi-initiator
systems.
F
Fabric, Fibre Channel. An interconnection that
receives addressed information which, in turn,
routes the information to its appropriate
destination.
FC. Feature code.
Fibre Channel. An optics cable utilizing
filaments to transmit data.
Fibre Channel arbitrated loop (FC-AL). In this
topology, two or more Fibre Channel end points
are interconncted through a looped interface.
Information is routed through the loop to its
destination.
Fibre Channel hub. In this topology, the hub
provides ports similar to switch ports and uses a
Fibre Channel arbitrated loop structure.
Fibre Channel switch (switched fabric). In this
topology, two or more end points are
interconnected through one or more switches.
Fibre Channel topologies. Shared loop host and
storage controllers.
FID. format identification field
fiducial. A reference point which guides the
cartridge-handling device to the tape subsystem
location.
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; for example, a brush and a
brush block that can be replaced individually or
as a single unit.
file. A set of related records, treated as a unit,
for example, in stock control, a file could consist
of a set of invoices.
file protected. Pertaining to a tape volume from
which data can be read only. Data cannot be
written on or erased from the tape.
format. The arrangement or layout of data on a
data medium.
FRU. Field replaceable unit.
G
GB. Gigabyte; 1 073 741 824 bytes of storage.
global command. A global command is a
command that affects multiple devices in the I/O
subsystem in a way that the control program
needs to be aware of.
H
host system. A data-processing system that is
used to prepare programs and the operating
environments for use on another computer or
controller.
I
immediate commands. Immediate commands
do not transfer data and receive channel end
Glossary 135