LOG SENSE | 6.Command Specification |
6.6.LOG SENSE 4Dh
Bit | 7 |
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| Operation | Code (4Dh) |
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1 |
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| Reserved |
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| PPC (0) |
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2 |
| PC |
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| Page Code |
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3 | (MSB) |
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4 |
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5 |
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| Parameter Pointer |
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6 |
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7 | (MSB) |
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| Allocation Length |
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9 |
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| Control |
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The LOG SENSE command provides a means for the initiator to retrieve statistical information maintained by the device about its own hardware or the installed media. It is a complementary command to the LOG SELECT command.
SP: The device does not have
PPC: The Parameter Pointer Control bit will always be set to ZERO. This indicates that the parameter data requested from the device will start with the parameter code specified in the Parameter Pointer field and return the number of bytes specified in the Allocation Length field in ascending order of parameter codes from the specified log page. A PPC bit of ZERO and a Parameter Pointer field of ZERO cause all available parameter data for that page code to be returned to the initiator. If the PPC bit is set or the Parameter Pointer is larger than the highest numbered parameter on the page, then the target will terminate the command with CHECK CONDITION status. The sense key will be set to ILLEGAL REQUEST and the ASC will be set to INVALID FIELD IN CDB. If the drive does not support a parameter code within this page then it will not return any data associated with this parameter.
PC: The Page Control field defines the type of parameter values to be selected. The page control field is defined below:
Table 6-8: Page Control field values
Value | Type of Parameter Values |
00b | Current Threshold Values |
01b | Current Cumulative Values |
10b | Default Threshold Values |
11b | Default Cumulative Values |
The Current Threshold Values and the Default Threshold Values are
The Current Cumulative Values are the values computed since the last reset of the device (either by
The Default Cumulative Values are the values to which each parameter gets initialized on a reset condition as described above. See description of individual pages/parameters below for more details.
SONY |