Seagate DiamondMax 17 Manual page 58

Glossary
LOGICAL FORMAT – The logical drive geometry that
appears to an AT system BIOS as defined by the drive tables
and stored in CMOS. With an installation program like Disk
Manager, the drive can be redefined to any logical
parameters necessary to adapt to the system drive tables.
LOOK AHEAD – The technique of buffering data into
cache RAM by reading subsequent blocks in advance to
anticipate the next request for data. The look ahead
technique speeds up disk access of sequential blocks of data.
LOW-LEVEL FORMATTING – Formatting that creates
the sectors on the platter surfaces so the operating system can
access the required areas for generating the file structure.
Maxtor drives are shipped with the low-level formatting
already done.
LOW PROFILE – Describes drives built to the 3 1/2-inch
form factor, which are only 1 inch high.
MB – See megabyte.
MEDIA – The magnetic film that is deposited or coated on
an aluminum substrate which is very flat and in the shape of
a disk. The media is overcoated with a lubricant to prevent
damage to the heads or media during head take off and
landing. The media is where the data is stored inside the disk
in the form of magnetic flux or polarity changes.
MEGABYTE (Mb) – A unit of measurement equal to
1,024 kilobytes, or 1,048,576 bytes except when referring to
disk storage capacity.
1 MB = 1,000,000 bytes when referring to disk storage
capacity. See also kilobyte.
MEGAHERTZ – A measurement of frequency in millions
of cycles per second.
MHz – See megahertz.
MICROPROCESSOR – The integrated circuit chip that
performs the bulk of data processing and controls the operation
of all of the parts of the system. A disk drive also contains a
microprocessor to handle all of the internal functions of the
drive and to support the embedded controller.
MICROSECOND (µs) – One millionth of a second
(.000001 sec.).
MILLISECOND (ms) – One thousandth of a second
(.001 sec.).
G-4 Maxtor DiamondMax 17 80-160GB Serial ATA Hard Disk Drive
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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 = 1,000,200 / 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.
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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.
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.
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