User Manual

SCSI Commands Reference Manual, Rev. J 278
www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)
3.74 WRITE SAME (16) command
The WRITE SAME (16) command (see table 238) requests that the device server transfer a single logical block from the data-out
buffer and write the contents of that logical block to the specified range of logical block addresses. Each logical block includes
user data and may include protection information, based on the WRPROTECT field and the medium format. The WRITE SAME
(16) command with the UNMAP bit supported is one of the possible commands that shall be implemented by device servers
supporting thin provisioning (see SBC-4).
NDOB bit
A NDOB bit set to zero specifies that the device server shall process the command using logical block data from the Data-Out Buffer. A NDOB
bit set to one specifies that:
a) the device server shall not transfer data from the Data-Out Buffer;
b) if the Logical Block Provisioning VPD page (see 5.2.13) is not supported or the LBPRZ field (see 5.2.13) is set to 000b or xx1b, then the
device server shall process the command as if the Data-Out Buffer contained user data set to all zeroes and protection information, if
any, containing:
A. the logical block guard field set to FFFFh;
B). the logical block reference tag field set to FFFF_FFFFh; and
C). the logical block application tag field set to FFFFh;
and
c) if the LBPRZ field is set to 010b, then the device server shall process the command as if the Data-Out Buffer contained user data set to
the provisioning initialization pattern and protection information, if any, containing:
A. the logical block guard field set to FFFFh;
B). the logical block reference tag field set to FFFF_FFFFh; and
C). the logical block application tag field set to FFFFh.
See the WRITE SAME (10) command (see 3.73) for the definitions of the other fields in this command.
Table 238 WRITE SAME (16) command
Bit
Byte
7 6 5 4 3 2 1 0
0 OPERATION CODE (93h)
1 WRPROTECT ANCHOR UNMAP Obsolete Obsolete NDOB
2 (MSB)
LOGICAL BLOCK ADDRESS. . .
9 (LSB)
10 (MSB)
NUMBER OF BLOCKS. . .
13 (LSB)
14 Reserved GROUP NUMBER
15 CONTROL