Sony DDS-4 Product Description Manual page 67

6. COMMAND SPECIFICATION
PPC:
The Parameter Pointer Control bit shall 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 shall terminate the command with CHECK CONDITION status. The sense key shall be set to ILLEGAL
REQUEST and the additional sense code shall be set to INVALID FIELD IN CDB.
If the drive does not support a parameter code within this page then it shall 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:
The Current Threshold Values and the Default Threshold Values are non-changeable and will both return the same
values - i.e. the maximum values that each parameter can attain. Note that for some parameters the term threshold value
has no meaning. See the description of individual pages/parameters below for more details.
The Current Cumulative Values are the values computed since the last reset of the device (either by power-cycling, BUS
DEVICE RESET or SCSI RESET). Note that for some parameters these values cannot be reset by any method. See
description of individual pages/parameters below for more details.
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.
6 - 16 SONY SDT-10000/SDT-11000 DDS Tape Drive
V alue Type of Parameter V alues
Current Threshold V alues
00b
01b Current Cumulative V alues
10b Default Threshold V alues
11b Default Cumulative V alues
Table 6-5: Page Control field values
LOG SENSE