SCSI Mode Select Command

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:

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.

Famous quotes containing the words mode, select and/or command:

    “That the mere matter of a poem, for instance—its subject, its given incidents or situation; that the mere matter of a picture—the actual circumstances of an event, the actual topography of a landscape—should be nothing without the form, the spirit of the handling, that this form, this mode of handling, should become an end in itself, should penetrate every part of the matter;Mthis is what all art constantly strives after, and achieves in different degrees.”
    —Walter Pater (1839–1894)

    “We hear the haunting presentiment of a dutiful middle age in the current reluctance of young people to select any option except the one they feel will impinge upon them the least.”
    —Gail Sheehy (b. 1937)

    “I, who should command a regiment,
    Do amble amiably here, O God,
    One of the neat ones in your awkward squad.”
    —Norman Cameron (b. 1905)