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HARD DISK – A type of storage medium
that retains data as magnetic patterns on a rigid
disk, usually made of an iron oxide or alloy
over a magnesium or aluminum platter.
Because hard disks spin more rapidly than
floppy disks, and the head flies closer to the
disk, hard disks can transfer data faster and
store more in the same volume.
HARD ERROR – A repeatable error in disk
data that persists when the disk is reread,
usually caused by defects in the media surface.
HEAD – The tiny electromagnetic coil and
metal pole piece used to create and read back
the magnetic patterns (write and read
information) on the media.
HIGH-LEVEL FORMATTING –
Formatting performed by the operating
system's format program. Among other
things, the formatting program creates the
root directory and file allocation tables. See
also low-level formatting.
HOME – Reference position track for
re-calibration of the actuator, usually the
outer track (track 0).
HOST ADAPTER – A plug-in board that
forms the interface between a particular type
of computer system bus and the disk drive.
I
INITIALIZE – See low level formatting.
INITIATOR – A SCSI device that requests
another SCSI device to perform an operation.
A common example of this is a system
requesting data from a drive. The system is the
initiator and the drive is the target.
INTERFACE – A hardware or software
protocol, contained in the electronics of the
disk controller and disk drive, that manages
the exchange of data between the drive and
computer.
INTERLEAVE – The arrangement of
sectors on a track. A 1:1 interleave arranges
the sectors so that the next sector arrives at the
read/write heads just as the computer is ready
to access it. See also interleave factor.
INTERLEAVE FACTOR – The number
of sectors that pass beneath the read/write
heads before the next numbered sector
arrives. When the interleave factor is 3:1, a
sector is read, two pass by, and then the next
is read. It would take three revolutions of the
disk to access a full track of data. Maxtor
drives have an interleave of 1:1, so a full track
of data can be accessed within one revolution
of the disk, thus offering the highest data
throughput possible.
INTERNAL DRIVE – A drive mounted
inside one of a computer's drive bays (or a
hard disk on a card, which is installed in one
of the computer's slots).
J
JUMPER – A tiny box that slips over two
pins that protrude from a circuit board. When
in place, the jumper connects the pins
electrically. Some board manufacturers use
Dual In-Line Package (DIP) switches instead
of jumpers.
JBOD - Just a Bunch of Drives
K
KILOBYTE (kB) – A unit of measure
10
consisting of 1,024 (2
) bytes.
L
LATENCY – The period of time during
which the read/write heads are waiting for the
data to rotate into position so that it can be
accessed. Based on a disk rotation speed of
3,662 rpm, the maximum latency time is 16.4
milliseconds, and the average latency time is
8.2 milliseconds.
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
Maxtor DiamondMax 8S 40GB SATA
GLOSSARY
G-4
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