Block Descriptor - Hitachi ULTRASTAR 15K450 HUS154530VLF400 Specifications

19.10.1.2 Block Descriptor

Table 144: Mode Parameter Block Descriptor
Byte 0 (MSB)
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5 (MSB)
Byte 6
Byte 7
The Block descriptor provides formatting information about the Number of Blocks (user addressable) to format at the speci-
fied Block Length.
• 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 contains the exact number of blocks.
• Density Code
- Always 0 for direct access devices.
• Block Length
The Block Length field reflects the number of bytes of user data per sector (not including any protection informa-
tion). When used with the MODE SELECT command, the Block length field must contain the value from 512 to 528
(8 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 param-
eter 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
Density code = 0
Block Length
Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
170
(LSB)
(LSB)