6.Command Specification
MODE SENSE
6-56
SONY AIT-5 drive SDX-1100V series Ver.1.0
Media Type:
The media value will be ZERO as only one media type is supported.
WP:
A Write Protected bit of ZERO indicates that the tape is write enabled. A Write Protected bit of one indicates
that the tape is write protected.
Buffered Mode:
if this bit is set to ZERO, the drive will not report a GOOD status on WRITE commands until the
data blocks are actually written on the tape. If set, the drive is in buffered mode and may report a GOOD status
on WRITE commands as soon as the data block has been transferred to the drive’s buffer. One or more blocks
may be buffered prior to writing to the tape. (Not support)
If the Buffered Mode field is ONE, then drive reports GOOD status on WRITE commands as soon as the data
block has been transferred to the buffer, this field will be set to ONE.
Speed Field:
will return ZERO as the drive only supports one speed.
Block Descriptor Length:
returns a value of 8, which specifies the length in bytes of the following Block
Descriptor. The drive only returns a single Block Descriptor.
Density Code:
Refer to Table 6-40 regarding the Density Code field.
Number of Blocks:
The Number of Blocks field is ZERO, indicating that an unspecified (or unknown) number of
the remaining logical blocks on the tape may have the media characteristics specified by the Block Descriptor.
Block Length:
The Block Length field specifies the length in bytes of each logical block transferred over the SCSI
bus. A Block Length of ZERO indicates that the length is variable. Any other value indicates the number of bytes
per block that the drive must handshake over the bus. This establishes Block Length such that the Transfer Length
for read, write command will be a block count not a byte count.
Note:
It is value of this field together with the Fixed bit Field in the READ, or WRITE commands that determine
whether the drive is in Fixed or Variable block mode. The minimum length is 4 and it always will be a multiple of 4.
Page Descriptor:
The supported pages are fully documented in the MODE SELECT clause of this Chapter.
PS:
When the Page Savable bit is set, this indicates that the page contains saved parameters. This bit will never
be set as there is no non-volatile RAM on the drive into which parameter data may be saved.
All fields not supported by the drive must be set to ZEROs.
