Glossary
This
glossary
provides
definitions
for
the
terminology
and
abbreviations
used
in
IBM
TotalStorage
DS4000
publications.
If
you
do
not
find
the
term
you
are
looking
for,
see
the
IBM
Glossary
of
Computing
Terms
located
at
the
following
Web
site:
This
glossary
also
includes
terms
and
definitions
from:
v
Information
Technology
Vocabulary
by
Subcommittee
1,
Joint
Technical
Committee
1,
of
the
International
Organization
for
Standardization
and
the
International
Electrotechnical
Commission
(ISO/IEC
JTC1/SC1).
Definitions
are
identified
by
the
symbol
(I)
after
the
definition;
definitions
taken
from
draft
international
standards,
committee
drafts,
and
working
papers
by
ISO/IEC
JTC1/SC1
are
identified
by
the
symbol
(T)
after
the
definition,
indicating
that
final
agreement
has
not
yet
been
reached
among
the
participating
National
Bodies
of
SC1.
v
IBM
Glossary
of
Computing
Terms.
New
York:
McGraw-Hill,
1994.
The
following
cross-reference
conventions
are
used
in
this
glossary:
See
Refers
you
to
(a)
a
term
that
is
the
expanded
form
of
an
abbreviation
or
acronym,
or
(b)
a
synonym
or
more
preferred
term.
See
also
Refers
you
to
a
related
term.
Abstract
Windowing
Toolkit
(AWT).
A
Java
graphical
user
interface
(GUI).
accelerated
graphics
port
(AGP).
A
bus
specification
that
gives
low-cost
3D
graphics
cards
faster
access
to
main
memory
on
personal
computers
than
the
usual
peripheral
component
interconnect
(PCI)
bus.
AGP
reduces
the
overall
cost
of
creating
high-end
graphics
subsystems
by
using
existing
system
memory.
access
volume.
A
special
logical
drive
that
allows
the
host-agent
to
communicate
with
the
controllers
in
the
storage
subsystem.
adapter.
A
printed
circuit
assembly
that
transmits
user
data
input/output
(I/O)
between
the
internal
bus
of
the
host
system
and
the
external
fibre-channel
(FC)
link
and
vice
versa.
Also
called
an
I/O
adapter,
host
adapter,
or
FC
adapter.
advanced
technology
(AT)
bus
architecture.
A
bus
standard
for
IBM
compatibles.
It
extends
the
XT
bus
architecture
to
16
bits
and
also
allows
for
bus
mastering,
although
only
the
first
16
MB
of
main
memory
are
available
for
direct
access.
agent.
A
server
program
that
receives
virtual
connections
from
the
network
manager
(the
client
program)
in
a
Simple
Network
Management
Protocol-Transmission
Control
Protocol/Internet
Protocol
(SNMP-TCP/IP)
network-managing
environment.
AGP.
See
accelerated
graphics
port.
AL_PA.
See
arbitrated
loop
physical
address.
arbitrated
loop.
One
of
three
existing
fibre-channel
topologies,
in
which
2
-
126
ports
are
interconnected
serially
in
a
single
loop
circuit.
Access
to
the
Fibre
Channel-Arbitrated
Loop
(FC-AL)
is
controlled
by
an
arbitration
scheme.
The
FC-AL
topology
supports
all
classes
of
service
and
guarantees
in-order
delivery
of
FC
frames
when
the
originator
and
responder
are
on
the
same
FC-AL.
The
default
topology
for
the
disk
array
is
arbitrated
loop.
An
arbitrated
loop
is
sometimes
referred
to
as
a
Stealth
Mode.
arbitrated
loop
physical
address
(AL_PA).
An
8-bit
value
that
is
used
to
uniquely
identify
an
individual
port
within
a
loop.
A
loop
can
have
one
or
more
AL_PAs.
array.
A
collection
of
fibre-channel
or
SATA
hard
drives
that
are
logically
grouped
together.
All
the
drives
in
the
array
are
assigned
the
same
RAID
level.
An
array
is
sometimes
referred
to
as
a
″
RAID
set.
″
See
also
redundant
array
of
independent
disks
(RAID),
RAID
level.
asynchronous
write
mode.
In
remote
mirroring,
an
option
that
allows
the
primary
controller
to
return
a
write
I/O
request
completion
to
the
host
server
before
data
has
been
successfully
written
by
the
secondary
controller.
See
also
synchronous
write
mode,
remote
mirroring,
Global
Copy,Global
Mirroring.
AT.
See
advanced
technology
(AT)
bus
architecture.
ATA.
See
AT-attached.
AT-attached.
Peripheral
devices
that
are
compatible
with
the
original
IBM
AT
computer
standard
in
which
signals
on
a
40-pin
AT-attached
(ATA)
ribbon
cable
followed
the
timings
and
constraints
of
the
Industry
Standard
Architecture
(ISA)
system
bus
on
the
IBM
PC
AT
computer.
Equivalent
to
integrated
drive
electronics
(IDE).
©
Copyright
IBM
Corp.
2006
177
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