IBM TOTAL STORAGE DS8000 User Manual
Page 365
program
On
a
computer,
a
generic
term
for
software
that
controls
the
operation
of
the
computer.
Typically,
the
program
is
a
logical
assemblage
of
software
modules
that
perform
multiple
related
tasks.
program-controlled
interruption
An
interruption
that
occurs
when
an
I/O
channel
fetches
a
channel
command
word
with
the
program-controlled
interruption
flag
on.
program
temporary
fix
(PTF)
A
temporary
solution
to,
or
bypass
of,
a
problem
diagnosed
by
IBM
as
the
result
of
a
defect
in
a
current
unaltered
release
of
a
licensed
program.
(GC)
promote
To
add
a
logical
data
unit
to
cache
memory.
protected
volume
In
AS/400,
a
disk
storage
device
that
is
protected
from
data
loss
by
RAID
techniques.
An
AS/400
host
does
not
mirror
a
volume
configured
as
a
protected
volume,
while
it
does
mirror
all
volumes
configured
as
unprotected
volumes.
The
DS8000,
however,
can
be
configured
to
indicate
that
an
AS/400
volume
is
protected
or
unprotected
and
give
it
RAID
protection
in
either
case.
protocol
data
unit
(PDU)
A
unit
of
data
specified
in
the
protocol
of
a
given
layer
and
consisting
of
protocol
control
information
for
the
layer
and,
possibly,
user
data
for
the
layer.
pSeries
The
product
name
of
an
IBM
e(logo)server
product
that
emphasizes
performance.
It
is
the
successor
to
the
RS/6000
family
of
servers.
pseudo
host
A
host
connection
that
is
not
explicitly
defined
to
the
DS8000
and
that
has
access
to
at
least
one
volume
that
is
configured
on
the
DS8000.
The
FiconNet
pseudo
host
icon
represents
the
FICON
protocol.
The
EsconNet
pseudo
host
icon
represents
the
ESCON
protocol.
The
pseudo
host
icon
labelled
Anonymous
represents
hosts
connected
through
the
FCP
protocol.
Anonymous
host
is
a
commonly
used
synonym
for
pseudo
host.
The
DS8000
adds
a
pseudo
host
icon
only
when
it
is
set
to
access-any
mode.
See
also
access-any
mode.
PTF
See
program
temporary
fix.
PV
Links
Short
for
Physical
Volume
Links,
an
alternate
pathing
solution
from
Hewlett-Packard
that
provides
for
multiple
paths
to
a
volume,
as
well
as
static
load
balancing.
R
R0
See
track-descriptor
record.
rack
See
enclosure.
RAID
See
redundant
array
of
independent
disks.
RAID
is
also
commonly
expanded
to
redundant
array
of
inexpensive
disks.
See
also
array.
RAID
5
A
type
of
RAID
that
optimizes
cost-effective
performance
while
emphasizing
use
of
available
capacity
through
data
striping.
RAID
5
provides
fault
tolerance
for
up
to
two
failed
disk
drives
by
distributing
parity
across
all
the
drives
in
the
array
plus
one
parity
disk
drive.
The
DS8000
automatically
reserves
spare
disk
drives
when
it
assigns
arrays
to
a
device
adapter
pair
(DA
pair).
See
also
device
adapter,
RAID
10,
and
redundant
array
of
independent
disks.
RAID
10
A
type
of
RAID
that
optimizes
high
performance
while
maintaining
fault
tolerance
for
up
to
two
failed
disk
drives
by
striping
volume
data
across
several
disk
drives
and
mirroring
the
first
set
of
disk
drives
on
an
identical
set.
The
DS8000
automatically
reserves
spare
disk
drives
when
it
assigns
arrays
to
a
device
adapter
pair
(DA
pair).
See
also
device
adapter,
RAID
5,
and
redundant
array
of
independent
disks.
random
access
A
mode
of
accessing
data
on
a
medium
in
a
manner
that
requires
the
storage
device
to
access
nonconsecutive
storage
locations
on
the
medium.
rank
One
or
more
arrays
that
are
combined
to
create
a
logically
contiguous
storage
space.
Glossary
345