Maxtor MaXLine II 250 Product Manual page 47

support the embedded controller.
MICROSECOND (µs) – One millionth of
a second (.000001 sec.).
MILLISECOND (ms) – One thousandth
of a second (.001 sec.).
MTTF – MTTF is a basic measure of
reliability for non-repairable systems. It
is the mean time expected until the first
failure of a piece of equipment. MTTF
is a statistical value and is meant to be
the mean over a long period of time and
large number of units. For constant
failure rate systems, MTTF is the
inverse of the failure rate. If failure rate
is in failures/million hours, MTTF =
1,000,000 / Failure Rate for
components with exponential
distributions.
MTTR – Mean Time To Repair. The
average time it takes to repair a drive
that has failed for some reason. This
only takes into consideration the
changing of the major sub-assemblies
such as circuit board or sealed housing.
Component level repair is not included
in this number as this type of repair is
not performed in the field.
N
NANOSECOND (ns)– One billionth of a
second (0.000000001 second).
O
OVERHEAD – The processing time of a
command by the controller, host
adapter or drive prior to any actual disk
accesses taking place.
OVERWRITE – To write data on top of
existing data, erasing it.
OXIDE – A metal-oxygen compound.
Most magnetic coatings are
combinations of iron or other metal
oxides, and the term has become a
general one for the magnetic coating
on tape or disk.
P
PARTITION – A portion of a hard disk
devoted to a particular operating
system and accessed as one logical
volume by the system.
PERFORMANCE – A measure of the
speed of the drive during normal
operation. Factors affecting
performance are seek times, transfer
rate and command overhead.
PERIPHERAL – A device added to a
system as an enhancement to the basic
CPU, such as a disk drive, tape drive or
printer.
PHYSICAL FORMAT – The actual
physical layout of cylinders, tracks,
and sectors on a disk drive.
PLATED MEDIA – Disks that are
covered with a hard metal alloy instead
of an iron-oxide compound. Plated
disks can store greater amounts of data
in the same area as a coated disk.
PLATTER – An disk made of metal (or
other rigid material) that is mounted
inside a fixed disk drive. Most drives
use more than one platter mounted on
a single spindle (shaft) to provide more
data storage surfaces in a small
package. The platter is coated with a
magnetic material that is used to store
data as transitions of magnetic
polarity.
POH – Acronym for power on hours.
The unit of measurement for Mean
Time Between Failure as expressed in
the number of hours that power is
applied to the device regardless of the
amount of actual data transfer usage.
See MTBF.
POSITIONER – See actuator.
R
REDUNDANT ARRAY OF
INDEPENDENT DISKS (RAID) - is a way
of storing the same data in different
places (thus, redundantly) on multiple
Maxtor MaXLine II 250/300GB
Glossary
G-6