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2.
Not Write-Protected
Write-Protected
Serpentine
Recording Method
About Tape Streamers
2.1.
Physical Elements
Tape streamer devices optimize their use in storing or
retrieving
user
access is sequential, position changes typically take
long time, when compared to direct-access devices like
disks.
The recording medium used with the Drive consists of a
flexible substrate coated with a magnetic material. The
recording medium is wound onto two reels.
Both
the
supply
encapsulated into a cartridge. Several standards exist,
covering the construction of cartridges for interchange.
A complete unit composed of the recording medium and its
physical carrier (the cartridge) is called a volume. In
tape streamers like the Tandberg SLR Product Line Tape
Drives, the volumes are removable.
When a volume is inserted it has the attribute of being
loaded
or
unloaded.
streamer device is capable of executing commands that
cause the medium to be moved (so-called media access
commands). A volume is unloaded when the media access
commands
can
not
commands report CHECK CONDITION status and a NOT READY
sense key).
2.2.
Data Storage Characteristics
The position on the medium where a pattern of recorded
signal may be written by one write component is called a
track or track set which may consist of either one, two
or four tracks, depending on the tape format used. On a
new
volume,
recording
mounting the volume and then by moving the tape from BOT
toward EOT. When EOT is approached, the direction of
recording is reversed and the Drive starts recording a
track set from EOT towards BOT. This process repeats the
number of times necessary to record all track sets. The
total number of track sets depends on the tape format
used. This method of recording is called serpentine.
2-1
Tandberg SLR Product Line SCSI Functional Specifications
data
in
a
sequential
reel
and
the
Loaded
is
be
executed
The
write-protected
whether
an
Initiator
write
information
attribute is controlled by the user of
the volume through the SAFE-switch on
the cartridges.
The recording medium has two physical
attributes
called
(BOT) and End-Of-Tape (EOT). BOT is at
the end of the medium that is attached
to the take-up reel. EOT is at the end
of the medium that is attached to the
supply reel.
of
a
track
manner.
take-up
reel
the
state
when
(that
is
when
state
determines
may
or
may
on
a
volume.
Beginning-Of-Tape
set
begins
Since
are
the
these
not
This
after
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