Seagate Fibre Channel Interface - Manual (Page 361)

Fibre Channel Interface Manual, Rev. D 347
12.71 XDWrite (32) command
The XDWrite (32) command requests that the target xor the data transferred with the data on the medium. The
resulting xor data is stored by the target until it is retrieved by an XDRead command.
The resulting xor data is retrieved by an XDRead command with starting logical block address and transfer
length fields that match, or is a subset of, the starting logical block address and transfer length of this com-
mand.
If the logical unit is reserved, a reservation conflict occurs when an XDWrite command is received from an ini-
tiator other than the one holding the logical unit reservation. The command is rejected with Reservation Con-
flict status if the reservation conflict is due to a logical unit reservation. The XDWrite command is evaluated for
extent reservation conflicts. XDWrite commands with a reservation conflict are terminated with Check Condi-
tion status and the sense key is set to Data Protect if any part of the XDWrite operation is prohibited by an
extent reservation.
Table 236: XDWrite (32) command (7Fh)
Bit
Byte
7 6 5 4 3 2 1 0
0 0 1 1 1 1 1 1 1
1
Control
2
:
6
Reserved
7
Additional CDB Length (18h)
8 (MSB)
Service Action (0004h)
9 (LSB)
10 Reserved DPO FUA Disable
Write
Reserved
11
Reserved
12 (MSB)
Logical Block Address
13
14
15
16
17
18
19 (LSB)
20
:
27
Reserved
28 (MSB)
Transfer Length
29
30
31 (LSB)
7Fh