11 mode select (6) command, Mode select (6) command – Seagate Fibre Channel Interface User Manual
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Fibre Channel Interface Manual, Rev. D
12.11
Mode Select (6) command
The Mode Select command provides a means for the initiator to specify medium, logical unit, or peripheral
device parameters to the disc drive. The drive also implements the Mode Sense command (see 12.13). Initia-
tors should issue Mode Sense prior to Mode Select to determine supported pages, page lengths, and other
parameters.
The drive maintains a common set of mode parameters shared by all initiators. If an initiator sends a Mode
Select command that changes any parameters, the drive generates a Unit Attention condition for all initiators
except the one that issued the Mode Select command. The drive sets the additional sense code to Mode
Parameters Changed.
Field definitions (listed alphabetically)
Control
See Control Bytes in Section 11.2.1.6.
Parameter List Length
The length (in bytes) of the Mode Select parameter list that is transferred during the Data Out phase.
0
No data will be transferred. This condition is not considered an error.
PF (Page Format)
1
The data sent by the initiator after the Mode Select header and the block descriptors (if any) complies with the Page
Format mode.
0
The data sent by the initiator after the Mode Select header and the block descriptors (if any) are vendor unique. The
disc drive does not interpret the PF bit. It assumes the Page Format mode.
SP (Save Pages)
1
The disc drive saves the savable pages. The format related parameters in the block descriptor, pages 3 and 4 are
saved during a Format command as well as a Mode Select command with SP = 1. The disc drive must update the
Current mode values with parameters included with this command, save the Current values of the savable parame-
ters, and report Good status only after the save operation is completed. The saved parameters are not changed if
an error is detected during the Mode Select command.
0
The saved parameter values are not changed.
The Mode Select parameter list (Table 139) contains a four-byte header, followed by zero or one block descrip-
tors, followed by the pages of Mode Select Parameters.
Acceptable values for the Mode Select parameter list for the disc drive are shown in Table 139.
Table 138: Mode Select (6) command (15h)
Bit
Byte
7
6
5
4
3
2
1
0
0
0
0
0
1
0
1
0
1
1
Reserved
PF
Reserved
SP
2
Reserved
3
Reserved
4
Parameter List Length
5
Control
15h
Table
number