Product manual

Glossary
G-8 Maxtor DiamondMax16
which is more accurate than stepper motors.
ROTATIONAL LATENCY – The delay
between when the controller starts looking
for a specific block of data on a track and
when that block rotates around to where it
can be read by the read/write head. On the
average, it is half of the time needed for a full
rotation (about 8 ms.).
S
SCSI – Acronym for Small Computer System
Interface, an American National Standards
Institute (ANSI) version of Shugart Associates'
SASI interface between the computer and
controller. SCSI has grown in popularity and
is one of the most flexible and intelligent
interfaces available.
SECTOR – A section of space along a track
on the disk, or the data that is stored in that
section. Hard disks most often have sectors
that are 512 data bytes long plus several bytes
overhead for error correcting codes. Each
sector is preceded by ID data known as a
header, which cannot be overwritten.
SEEK – A movement of the disk read/write
head in or out to a specific track.
SERVO DATA – Magnetic markings
written on the media that guide the
read/write heads to the proper position.
SERVO SURFACE – A separate surface
containing only positioning and disk timing
information but no data.
SETTLE TIME – The interval between
when a track to track movement of the head
stops, and when the residual vibration and
movement dies down to a level sufficient for
reliable reading or writing.
SHOCK RATING – A rating (expressed in
Gs) of how much shock a disk drive can
sustain without damage.
SOFT ERROR – An error in reading data
from the disk that does not recur if the same
data is reread. Often caused by power
fluctuations or noise spikes.
SOFT SECTORED – Disks that mark the
beginning of each sector of data within a track
by a magnetic pattern.
SPINDLE – The center shaft of the disk
upon which the drive’s platters are mounted.
SPUTTER – A type of coating process used
to apply the magnetic coating to some
high-performance disks. In sputtering, the
disks are placed in a vacuum chamber and the
coating is vaporized and deposited on the
disks. The resulting surface is hard, smooth,
and capable of storing data at high density.
Maxtor disk drives use sputtered thin film
disks.
STEPPER – A type of motor that moves in
discrete amounts for each input electrical
pulse. Stepper motors used to be widely used
for read/write head positioner, since they can
be geared to move the head one track per
step. Stepper motors are not as fast or reliable
as the rotary voice coil actuators which
Maxtor disk drives use.
SUBSTRATE – The material the disk
platter is made of beneath the magnetic
coating. Hard disks are generally made of
aluminum or magnesium alloy (or glass, for
optical disks) while the substrate of floppies is
usually mylar.
SURFACE – The top or bottom side of the
platter which is coated with the magnetic
material for recording data. On some drives
one surface may be reserved for positioning
information.
T
TERABYTE (TB) – A unit of measurement
to 1,024 gigabytes (GB), or
1,099,511,627,776 bytes, except when
referring to disk storage capacity. Storage
capacities of one or more terabytes is achieved
by installing multiple hard drive in a RAID
system. 1 TB = 1,000,000,000,000 bytes
when referring to disk storage capacity. See
also gigabyte.
THIN FILM – A type of coating, used for
disk surfaces. Thin film surfaces allow more