Quantum DLT 8000 Product Manual page 190

SCSI Commands
LOG SENSE Command (4Dh) (continued)
Table 5–19 LOG SENSE Command Descriptor Block — Field Descriptions
Field Name
PPC
SP
PC
5-46
Description
Parameter Pointer Control. This bit must be set to 0. A PPC of 0
indicates that the parameter data requested from the device starts
with the parameter code specified in the Parameter Pointer field
(Bytes 5 - 6) and return the number of bytes specified in the
Allocation Length field (Bytes 7 - 8) in ascending order of parameter
codes from the specified log page.
Note that the current implementation of the READ/WRITE
COMPRESSION page does not support a PPC other than 0. If PPCbit is
set, then the target terminates the command with CHECK CONDITION
status, sense key set to ILLEGAL REQUEST, and additional sense code
set to INVALID FIELD IN CDB.
Save Parameters. Not supported, must be set to 0. If for some reason
the Save Parameters bit is set, the command terminates with a CHECK
CONDITION status with a sense key of ILLEGAL REQUEST and an ASC
of INVALID FIELD IN CDB.
Page Control. This field defines the type of parameter values to be
returned:
PC Type of Parameter Values
00b Threshold Values
01b Cumulative Values
10b Default Threshold Values
11b Default Cumulative Values
The Default Threshold Values are the maximum values that each
parameter can attain.
The Current Cumulative Values are the values computed since
the last reset of the device (either via power-cycle, BUS DEVICE
RESET, or SCSI RESET.
The Default Cumulative Values are the values to which each
parameter is initialized at a reset condition. Default values are
zero.
By default, Current Threshold Values = Default Threshold Values.
Note that all types of parameter values are changeable via LOG
SELECT.
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