Regenerate Command (82H) - Seagate SCSI Interface Product Manual

SCSI Interface Product Manual, Rev. J
5.30

Regenerate command (82h)

The Regenerate command (see Table 145) requests that the target write to the buffer the Xor data generated
from its own medium and the specified source devices. The target, acting as a temporary initiator, issues Read
commands to retrieve the specified data. For additional information about Xor commands, see Section 5.55.1.
The resulting Xor data is retained in the target's buffer until it is retrieved by an XDRead command with a start-
ing Logical Block Address and Transfer Length that match the Logical Block Address and Regenerate Length
of this command.
Table 145: Regenerate command (82h)
Bit 7
Byte
0 Operation Code (82h)
1
2 (MSB)
3
4
5
6 (MSB)
7
8
9
10 (MSB)
11
12
13
14 Reserved
15 Control [8]
Notes.
[1] If the Disable Page Out (DPO) bit is set to one, no data is cached. The DPO bit is only meaningful if the
RCD bit of Mode Select Page 8 is set false (caching enabled).
[2] A Force Unit Access (FUA) bit of one indicates that the Write command shall not return Good status until
the logical blocks have actually been written on the media. The FUA bit is only meaningful if the WCE bit
of Mode Sense page 8 is true.
[3] If the Intermediate Data (IntData) bit is set to zero, then intermediate data is not sent with the Rebuild
parameter list. If the bit is set to one, the Rebuild parameter list includes Intermediate Data. The length of
the intermediate data can be calculated by multiplying the rebuild length times the block size. This data
shall be treated as an additional source, and an Xor operation performed with it and the data from the
specified sources.
[4] The Port Control field is defined in Table 146. If the Port Control field has a value of 01b and the target is
not a multiple port device the command shall be terminated with a Check Condition status. The sense
data shall be set to Illegal Request: Invalid Field in CDB.
Table 146: Port Control field
Value Description
00 The target transfers the data using the same port that received the command.
01 The target transfers the data using a different port than that which received the
command.
10 The target transfers the data using one port of the target's choice.
11 The target transfers the data using one or more ports of the target's choice.
6 5
Reserved
4 3
DPO [1] FUA [2]
Logical Block Address [5]
Regenerate Length [6]
Parameter List Length [7]
2 1
IntData [3] Port Control [4]
185
0
(LSB)
(LSB)
(LSB)