Block Descriptor - IBM Ultrastar 36LZX Specifications

8.8.1.2 Block Descriptor

Byte 0
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
Figure 79. MODE Parameter Block Descriptor
The Block descriptor provides formatting information about the Number of Blocks (user addressable) to
format at the specified Block Length.
Ÿ Number of Blocks
When used with the MODE SELECT command, the Number of Blocks field must be
- Zero to indicate not to change available blocks
- 0xFFFFFFFF to indicate all available blocks
- The exact number of blocks in the data area of the drive, which can be obtained with the MODE
SENSE
- The number of blocks less than exact one, in order to CLIP the number of blocks
Any other value is invalid and causes the command to fail with CHECK CONDITION status.
When used with the MODE SENSE command, the field contain exact number of blocks.
Ÿ Block Length
When used with the MODE SELECT command, the Block length field must contain the value from
512 to 528 (2 bytes step) or zero. Otherwise the drive will terminate the command with CHECK
CONDITION status.
A Format Unit command is required to cause these parameters to become current only if the block
length parameter is different from the current block length.
When used with the MODE SENSE command, the field is dependent on how the media is currently
formatted.
Number of Blocks (MSB)
Density code = 0
Block Length
Ultrastar 36LZX hard disk drive specifications
(LSB)
95