SCSI Mode Select Command
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The SCSI Mode Select command is used to modify device information contained in mode pages in a SCSI target device. There are two different versions of the command, a 6 byte version and a 10 byte version.
The CDB structure for the Mode Select(6) command is[1]:
| bit→ ↓byte |
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|---|---|---|---|---|---|---|---|
| 0 | Operation code = 15h | |||||||
| 1 | LUN | PF | Reserved | SP | ||||
| 2 | Reserved | |||||||
| 3 | Reserved | |||||||
| 4 | Parameter list length | |||||||
| 5 | Control | |||||||
The CDB structure for the Mode Select(10) command is:
| bit→ ↓byte |
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|---|---|---|---|---|---|---|---|---|
| 0 | Operation code = 55h | |||||||
| 1 | LUN | PF | Reserved | SP | ||||
| 2 | Reserved | |||||||
| 3 | Reserved | |||||||
| 4 | Reserved | |||||||
| 5 | Reserved | |||||||
| 6 | Reserved | |||||||
| 7–8 | Parameter list length | |||||||
| 9 | Control | |||||||
The special control fields in the CDB have the following meaning:
- PF - Page Format:
- 0 - SCSI-1 compliant (vendor-specific)
- 1 - SCSI-2 compliant
- SP - Save Pages - if this bit is one then the target will save any saveable updates to non-volatile memory or media area.
[edit] References
- ^ "SCSI Primary Commands - 4 (SPC-4)" (PDF). http://www.t10.org/cgi-bin/ac.pl?t=f&f=spc4r30.pdf. Retrieved 2011-03-31.
