Seagate DiamondMax 17 Manual page 55

A
ACCESS – (v) Read, write, or update information on some
storage medium, such as a disk. (n) One of these operations.
ACCESS TIME – The interval between the time a request
for data is made by the system and the time the data is
available from the drive. Access time includes the actual seek
time, rotational latency, and command processing overhead
time. See also seek, rotational latency, and overhead.
ACTUATOR – Also known as the positioner. The internal
mechanism that moves the read/write head to the proper
track. The Maxtor actuator consists of a rotary voice coil and
the head mounting arms. One end of each head mounting
arm attaches to the rotor with the read/write heads attached
at the opposite end of each arm. As current is applied to the
rotor, it rotates, positioning the heads over the desired
cylinder on the media.
ALLOCATION – The process of assigning particular areas
of the disk to particular files. See also allocation unit.
ALLOCATION UNIT – An allocation unit, also known
as a cluster, is a group of sectors on the disk that can be
reserved for the use of a particular file.
AVERAGE SEEK TIME – The average time it takes for
the read/write head to move to a specific location. To
compute the average seek time, you divide the time it takes
to complete a large number of random seeks all over the disk
by the number of seeks performed.
B
BACKUP – A copy of a file, directory, or volume on a
separate storage device from the original, for the purpose of
retrieval in case the original is accidentally erased, damaged,
or destroyed.
BAD BLOCK – A block (usually the size of a sector) that
cannot reliably hold data because of a media flaw or
damaged format markings.
BAD TRACK TABLE – A label affixed to the casing of a
hard disk drive that tells which tracks are flawed and cannot
hold data. The listing is typed into the low-level formatting
program when the drive is being installed. Because Maxtor
disk drive's defect-management scheme handles all such
flaws automatically, there is no need to concern yourself
with bad track tables.
BIT – Abbreviation for binary digit. A binary digit may
have one of two values—1 or 0. This contrasts with a
decimal digit, which may have a value from 0 to 9. A bit is
one of the logic 1or logic 0 binary settings that make up a
byte of data. See also byte.
BLOCK – A sector or group of sectors.
BPI – Abbreviation for bits per inch. A measure of how
densely information is packed on a storage medium. Flux
changes per inch is also a term commonly used in describing
storage density on a magnetic surface.
BUFFER – An area of RAM reserved for temporary
storage of data that is waiting to be sent to a device that is
not yet ready to receive it. The data is usually on its way to
or from the disk drive or some other peripheral device.
BUS – The part of a chip, circuit board, or interface
designed to send and receive data.
BYTE – The basic unit of computer memory, large enough
to hold one character of alphanumeric data. Comprised of
eight bits. See also bit.
CACHE – Random-access memory used as a buffer
between the CPU and a hard disk. Information more likely
to be read or changed is placed in the cache, where it can be
accessed more quickly to speed up general data flow.
CAPACITY – The amount of information that can be
stored on a disk drive. The data is stored in bytes, and
capacity is usually expressed in megabytes.
CDB – Command Descriptor Block. The SCSI structure
used to communicate requests from an initiator (system) to
a target (drive).
CLEAN ROOM – An environmentally controlled
dust-free assembly or repair facility in which hard disk drives
are assembled or can be opened for internal servicing.
CLUSTER – A group of sectors on a disk drive that is
addressed as one logical unit by the operating system.
CONTROLLER – Short form of disk controller. The chip
or complete circuit that translates computer data and
commands.
CONTROLLER CARD – An adapter holding the
control electronics for one or more hard disks, usually
installed in a slot in the computer.
CPU – Acronym for Central Processing Unit. The
microprocessor chip that performs the bulk of data
processing in a computer.
Maxtor DiamondMax 17 80-160GB Serial ATA Hard Disk Drive
Glossary
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