Commands 77
Commands
Mode Block Descriptor
The format of the Mode Parameter block descriptor is as follows:
Mode Parameter Block Descriptor Fields:
2 The drive will report GOOD status for WRITE and WRITE FILEMARKS commands as soon
as all the data or marks specified in the command have been transferred to the data
buffer and all buffered data from different initiators has been successfully written to
the tape. This is the maximum value.
Speed 0 The Speed field is not used and should be zero.
Block Descriptor
Length
Only the values 0 and 8 are valid. Any value other than 0 or 8,
CHECK CONDITION status is
reported. See the Parameter List check for details of the sense data generated.
0 No block descriptor is being transferred.
8 The Mode Parameter header must be followed by the 8-byte block descriptor
described in the next section.
7 6 5 4 3 2 1 0
0
Density Code
1
(MSB)
Number of Blocks (0)
3
(LSB)
4
Reserved (0)
5
(MSB)
Block Length [0 or 800h]
7
(LSB)
Density Code This specifies the format of the media loaded in the drive. See “REPORT DENSITY SUPPORT
44h” on page 123
for details.
Block Length This indicates the size of fixed blocks for fixed mode
READ and WRITE commands. It is also used in
the decision process on whether to report an illegal length record on reads.
00h The default value when the drive is in normal tape drive mode.
