Appendix
D
Glossary
n s Nanosecond (10-
9
seconds)
One
A true signal value.
Reconnect
The function that occurs when a target selects an initiator to continue an operation after a
disconnect.
Reserved
The
tenn
used for bits, bytes, fields, and code values that are set aside for future
standardization.
SCSI
address
SCSI
ID
SCSI
device
Sector
Shipping/
Landing
Zone
Signal
assertion
Signal
negation
Signal
release
Status
Surface
Target
Track
Vendor
unique
Winchester
Technology
The octal representation
of
the unique address (0-7) assigned to an SCSI device. This
address would nonnally be assigned
and
set in the SCSI device during system installation.
The bit-significant representation
of
the SCSI address referring to one
of
the signal lines
DB(7-O).
A host computer adapter
or
a peripheral controller
or
an intelligent peripheral that can
be
attached to the SCSI bus.
A physical portion
of
a track
on
the disk which is used to store data. The physical sector
size is set at 512 bytes on the
ProDrive, plus 6 bytes for ECC. Each sector is preceded
by
10 data, which cannot
be
overwritten.
A circular area inside
of
track 833. The heads are pulled over this area whenever DC
power is removed
or
the disks slow below 3423 RPM for more than 2 sec. This area is
used to prevent the heads from touching the surface in data areas, adding to the data
integrity and reliability
of
Quantum drives.
The act
of
driving a signal to the true state.
The act
of
driving a signal to the false state
or
allowing the cable tenninators to bias
the signal to the false state (by placing the driver in the high impedance condition).
The act
of
allowing the cable tenninators to bias the signal to the false state (by placing the
driver in the high impedance condition).
One
byte
of
infonnation sent from a target to an initiator upon completion
of
each
command.
One side
of
a disk in the drive. Surface 0 is the area
of
the bottom disk where read/write
head
0 writes and reads data.
An
SCSI device that perfonns an operation requested by an initiator.
A ring
of
constant radius on the surface
of
a disk where data are recorded.
Indicates bits, fields,
or
code values that are vendor specific.
When used in reference to a disk drive, means that the drive uses continuously
loaded, low mass, high compliance head assemblies. Both the head assemblies and the disks
operate in a sealed, contamination free environment
to
allow flying heights
of
II
microinches
or
less. As the heads are continuously loaded, they will contact the media
surface when the disk is not spinning.
To
prevent damaging the media
or
heads, overcoated
media is used.
lJ.2 Appendix D
Glossary
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