User Manual

SCSI Commands Reference Manual, Rev. J 233

www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)

Table 206 defines an UNMAP block descriptor.

UNMAP LOGICAL BLOCK ADDRESS

The UNMAP LOGICAL BLOCK ADDRESS field contains the first LBA of the UNMAP block descriptor to be unmapped.

NUMBER OF LOGICAL BLOCKS field

The NUMBER OF LOGICAL BLOCKS field contains the number of LBAs to be unmapped beginning with the LBA specified by the UNMAP LOGI-

CAL BLOCK ADDRESS field.

If the NUMBER OF LOGICAL BLOCKS is set to zero, then no LBAs shall be unmapped for this UNMAP block descriptor. This condition shall not be

considered an error.

If the LBA specified by the UNMAP LOGICAL BLOCK ADDRESS field plus the number of logical blocks exceeds the capacity of the

medium, then the device server shall terminate the command with CHECK CONDITION status with the sense key set to ILLEGAL

REQUEST and the additional sense code set to LOGICAL BLOCK ADDRESS OUT OF RANGE.

If the total number of logical blocks specified in the UNMAP block descriptor data exceeds the value indicated in the MAXIMUM

UNMAP LBA COUNT field in the Block Limits VPD page (see 5.4.5), or if the number of UNMAP block descriptors exceeds the

value of the MAXIMUM UNMAP PARAMETER COUNT field in the Block Limits VPD page, then the device server shall terminate the

command with CHECK CONDITION status with the sense key set to ILLEGAL REQUEST and the additional sense code set to

INVALID FIELD IN PARAMETER LIST.

Table 206 UNMAP block descriptor

Bit

Byte

7 6 5 4 3 2 1 0

0 (MSB)

UNMAP LOGICAL BLOCK ADDRESS.....

7 (LSB)

8 (MSB)

NUMBER OF LOGICAL BLOCKS....

11 (LSB)

Reserved.....