Reference Guide

Chapter 4 SCSI Commands
LOG SENSE Command (4Dh)
DLT-S4 Interface Reference Guide 67
Table 39 LOG SENSE
Command Descriptor Block
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Field Descriptions
Field Description
PPC Parameter Pointer Control. When set to 0, indicates that the parameter data
requested from the drive starts with the parameter code specified in the Parameter
Pointer field (bytes 5 – 6) and returns the number of bytes specified in the
Allocation Length field (bytes 7 – 8) in ascending order of parameter codes from
the specified log page. When set to 1, the drive returns only the parameters that
have changed since the last time the page was read.
SP Save Parameters. Must be set to 0.
PC Page Control. This field defines the type of parameter values to be returned:
Code 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 drive by power-cycle,
TARGET RESET, SCSI RESET, or FCP TARGET RESET.
• Some parameters reset to their default value due to other events, such as
loading a new medium.
• The Default Cumulative values are the values to which each parameter is
initialized at a reset condition. Default values are 0.
• By default, Current Threshold Values are set to Default Threshold Values.
Page Code The Page Code field identifies the log page the initiator requested. The drive
supports the following pages:
Page
Code
Page Definition Refer to
00h Supported Pages Log Page (Page 00h) page 69
03h/02h Read (Page 03h) / Write (Page 02h) Error Log Pages page 69