IBM TOTAL STORAGE DS8000 User Manual
Page 356
Global
Mirror
An
optional
capability
of
the
DS8000
remote
mirror
and
copy
feature
that
provides
a
2-site
extended
distance
remote
copy.
Data
that
is
written
by
the
host
to
the
storage
unit
at
the
local
site
is
automatically
maintained
at
the
remote
site.
See
also
Metro
Mirror
and
Remote
Mirror
and
Copy.
group
In
DS8000
documentation,
a
nickname
for
two
different
kinds
of
groups,
depending
on
the
context.
See
disk
pack
or
Copy
Services
server
group.
H
HA
See
host
adapter.
HACMP
See
High-Availability
Cluster
Multi-Processing.
hard
disk
drive
(HDD)
1)
A
storage
medium
within
a
storage
server
used
to
maintain
information
that
the
storage
server
requires.
2)
A
mass
storage
medium
for
computers
that
is
typically
available
as
a
fixed
disk
(such
as
the
disks
used
in
system
units
of
personal
computers
or
in
drives
that
are
external
to
a
personal
computer)
or
a
removable
cartridge.
hardware
service
manager
(HSM)
An
option
on
an
AS/400
or
iSeries
host
that
enables
the
user
to
display
and
work
with
system
hardware
resources
and
to
debug
input-output
processors
(IOP),
input-output
adapters
(IOA),
and
devices.
HCD
See
Hardware
Configuration
Data.
HDA
See
head
and
disk
assembly.
HDD
See
hard
disk
drive.
hdisk
An
AIX
term
for
storage
space.
head
and
disk
assembly
(HDA)
The
portion
of
an
HDD
associated
with
the
medium
and
the
read/write
head.
heartbeat
A
status
report
sent
at
regular
intervals
from
the
DS8000.
The
service
provider
uses
this
report
to
monitor
the
health
of
the
call
home
process.
See
also
call
home,
heartbeat
call
home
record,
and
remote
technical
assistance
information
network.
heartbeat
call
home
record
Machine
operating
and
service
information
sent
to
a
service
machine.
These
records
might
include
such
information
as
feature
code
information
and
product
logical
configuration
information.
hierarchical
storage
management
1)
A
function
in
storage
management
software,
such
as
Tivoli
Storage
Management
or
Data
Facility
Storage
Management
Subsystem/MVS
(DFSMS/MVS),
that
automatically
manages
free
space
based
on
the
policy
that
the
storage
administrator
sets.
2)
In
AS/400
storage
management,
an
automatic
method
to
manage
and
distribute
data
between
the
different
storage
layers,
such
as
disk
units
and
tape
library
devices.
High-Availability
Cluster
Multi-Processing
(HACMP)
Software
that
provides
host
clustering,
so
that
a
failure
of
one
host
is
recovered
by
moving
jobs
to
other
hosts
within
the
cluster.
high-speed
link
(HSL)
A
hardware
connectivity
architecture
that
links
system
processors
to
system
input/output
buses
and
other
system
units.
home
address
A
nine-byte
field
at
the
beginning
of
a
track
that
contains
information
that
identifies
the
physical
track
and
its
association
with
a
cylinder.
hop
Interswitch
connection.
A
hop
count
is
the
number
of
connections
that
a
particular
block
of
data
traverses
between
source
and
destination.
For
example,
data
traveling
from
one
hub
over
a
wire
to
another
hub
traverses
one
hop.
host
See
host
system.
host
adapter
A
physical
subunit
of
a
storage
server
that
provides
the
ability
to
attach
to
one
or
more
host
I/O
interfaces.
host
name
The
Internet
address
of
a
machine
in
the
network.
The
host
name
can
be
entered
in
the
host
definition
as
the
fully
qualified
domain
name
of
the
attached
host
system,
such
as
mycomputer.city.company.com
,
or
336
IBM
TotalStorage
DS8000:
Messages
Reference