SCSI Log Sense Command

The SCSI Log Sense command is used to obtain current data from log pages in a SCSI target device. The CDB structure for the Log Sense command is:

SCSI Log Sense
bit→
↓byte		 7 6 5 4 3 2 1 0
0 Operation Code = 0x4D
1 LUN Reserved Obsolete SP
2 PC PAGE CODE
3 SUBPAGE CODE
4 Reserved
5 PARAMETER POINTER
6
7 ALLOCATION LENGTH
8
9 Control

The special parameter fields in the CDB have the following meaning:

  • SP - Save Parameters - if this is one then the target should save all saveable log parameters to a non-volatile memory or media area.
  • PC - Page Control - this indicates which type of values should be returned:
    • 00 - Current Threshold Values
    • 01 - Current Cumulative Values
    • 10 - Default Threshold Values
    • 11 - Default Cumulative Values
  • Parameter Pointer indicates the first parameter code to be returned.
  • Allocation Length in bytes

If the Parameter Pointer is zero and the Allocation Length is large enough then all parameters are returned.

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