IBM DS8000 User Manual page 230

maximum coordination time
The value in milliseconds that indicates
the maximum time that is allowed for
host I/O to be delayed during the
coordination of the primary volumes of
an Global Mirror session. The default is
50 milliseconds if this value is set to zero.
MB See megabyte.
MC See IBM System Storage Management
Console.
MCA See Micro Channel
MDM See Multiple Device Manager.
mean time between failures (MTBF)
1) A projection of the time that an
individual unit remains functional. The
time is based on averaging the
performance, or projected performance, of
a population of statistically independent
units. The units operate under a set of
conditions or assumptions.
2) For a stated period in the life of a
functional unit, the mean value of the
lengths of time between consecutive
failures under stated conditions. (I) (A)
medium
For a storage unit, the disk surface on
which data is stored.
megabyte (MB)
1) For processor storage, real and virtual
storage, and channel volume, 2
576 bytes.
2) For disk storage capacity and
communications volume, 1 000 000 bytes.
Metro Mirror
A function of a storage server that
maintains a consistent copy of a logical
volume on the same storage server or on
another storage server. All modifications
that any attached host performs on the
primary logical volume are also
performed on the secondary logical
volume. See also Remote Mirror and Copy
and Global Copy.
MES See miscellaneous equipment specification.
MIB See management information base.
Micro Channel architecture (MCA)
The rules that define how subsystems and
adapters use the Micro Channel bus in a
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architecture.
20
or 1 048
computer. The architecture defines the
services that each subsystem can or must
provide.
®
Microsoft Internet Explorer
Web browser software manufactured by
Microsoft.
migration
The replacement of a system or subsystem
with a different type of system or
subsystem, such as replacing a SCSI host
adapter with a fibre-channel host adapter.
In the context of data migration regarding
the DS8000, the transfer of data from one
storage unit to another, such as from a
3390 to the DS8000.
MIH See missing-interrupt handler.
mirrored pair
Two units that contain the same data. The
system refers to them as one entity.
mirroring
In host systems, the process of writing the
same data to two disk units within the
same auxiliary storage pool at the same
time.
miscellaneous equipment specification (MES)
IBM field-installed change to a machine.
missing-interrupt handler (MIH)
An MVS and MVS/XA
tracks I/O interrupts. MIH informs the
operator and creates a record whenever
an expected interrupt fails to occur before
a specified elapsed time is exceeded.
MLC See machine level control.
mobile solutions terminal (MoST)
The mobile terminal used by service
personnel.
mode conditioning patch cable
A cable that converts a single-mode signal
from a longwave adapter into a light
signal that is appropriate for multimode
fibre. Another mode conditioning patch
cable is required at the terminating end of
the multimode fibre to convert the signal
back to a single-mode signal for a
longwave adapter.
Model 100
A 2105 Model 100, often simply referred
to as a Mod 100, is an expansion
enclosure for the Enterprise Storage
Server. See also 2105.
™
facility that