Write; Command Description - Tandberg Data SLR7-140 PROGRAMMER Manual

30.

Write

30.1. Command Description

The WRITE command transfers one or more blocks from the
Initiator to the tape at the current tape position.
The Fixed (FIX) bit specifies both the meaning of the
Transfer Length
variable length block(s) are to be transferred. The data
to be written will be transferred during the data-out
phase of the command.
When the FIX bit is set to zero, the Drive is requested
to transfer a single variable length data block. The
Transfer Length specifies the length of the block in
number of bytes.
When the FIX bit is set to one, the Drive is requested
to transfer a
Transfer Length
transfer. All blocks will be of equal length. The length
used is the length reported by the MODE SENSE command
(the Block Size field of the Block Descriptor List).
Note that a FIX bit of one is not legal when the Drive
has been set into Variable Block mode. Variable Block
mode is in effect when the Block Size field in the Block
Descriptor List of the MODE SELECT command is set to
zero (000000h). See the MODE SELECT command for further
details.
If the requested Transfer Length is zero, the Drive will
transfer no data and the logical tape position will not
be changed. This will not be considered an error.
Upon termination
logical tape position
(fixed or variable) written (end-of-media side).
The WRITE command can operate in unbuffered and buffered
mode. For unbuffered
return GOOD status
successfully written to the medium. For buffered opera-
tion, the Drive may return GOOD status as soon as all
data blocks are successfully transferred to the Drive's
data buffer. The data blocks will not be written to the
medium before the amount of data in the Drive's data
buffer exceeds the Write Buffer Full Ratio (see MODE
SELECT command).
When operating
command with the IMM bit set to zero may be issued when
completing a WRITE operation to ensure that all the
buffered data and the tapemarks are written to the tape.
A write operation may commence from BOP, from EOD or,
when certain conditions
positions on the media.
If disconnection is allowed, the Drive will disconnect
when executing this command.
30-1 Tandberg SLR Product Line SCSI Functional Specifications
field and whether
number of fixed
specifies the
of a successful
will be
operation,
until all
in buffered mode;
are satisfied,
fixed-length
length blocks.
number of blocks
WRITE command,
after the last
the Drive will
data blocks
a WRITE FILEMARKS
from
or
The
to
the
block
not
are
other