Seagate Fibre Channel Interface - Manual (Page 357)

Fibre Channel Interface Manual, Rev. D 343
12.69 XDRead (32) command
The XDRead (32) command requests that the target transfer the xor data generated by an XDWrite or Regen-
erate command to the initiator.
If the logical unit is reserved, a reservation conflict occurs when an XDRead 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 XDRead command is evaluated for
extent reservation conflicts. XDRead commands with a reservation conflict is terminated with Check Condition
status and the sense key is set to Data Protect if any part of the XDRead operation is prohibited by an extent
reservation.
The xor data transferred is identified by the logical block address and transfer length. The logical block address
and transfer length is the same as, or a subset of, those specified in a prior XDWrite or Regenerate command.
If a match is not found, the command is terminated with a Check Condition status. The sense data is set to Ille-
gal Request: Invalid Field in CDB.
Table 234: XDRead (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 (0003h)
9 (LSB)
10
Reserved
11
Reserved
12 (MSB)
Logical Block Address
13
14
15
16
17
18
19 (LSB)
20
:
27
Reserved
28 (MSB)
Byte Transfer Length
29
30
31 (LSB)
7Fh