Maxtor QUICKVIEW ATA - Manual (Page 55)

Glossary
Maxtor QuickView 400/500GB Serial ATA Hard Disk Drive G-1
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.
C
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.