User's Guide

Page 62 DDS-4 SCSI Interface Manual, Rev. B
Byte
Bits
7 6 5 4 3 2 1 0
0 MSB—Parameter Code
1 Parameter Code—LSB
2 Parameter Control
3 Parameter Length (n-3)
4 Parameter Value
N Parameter Value
The Parameter Code field identifies the log parameter being returned to the initiator.
If the Parameter Pointer field of the CDB is zero, the parameter code of the first log
parameter indicates the first parameter code supported by the drive for this log
page. Parameter codes are always returned in ascending order.
All of the bits in byte 2 of the log parameter are collectively referred to as the
Parameter Control byte. The bit descriptions as they are returned by the LOG
SENSE command are given in the following table.
Bit Name Bytes Bits Description
Disable Update (DU) 2 7 When set (1), this bit indicates that the particular
parameter is not to be updated by the drive. This bit is
set by the drive when the accumulated value reaches its
maximum. It is also returned set if the host set the bit for
the last LOG SELECT command. The default is zero.
For parameter types other than threshold and
accumulated values, this bit is always 0.
Disable Save (DS) 2 6 A DS bit of zero indicates that the target supports saving
for the specified log parameter. A DS bit of one
indicates that the target does not support saving for the
specified log parameter in response to Log Select
command.
Target Save Disable
(TSD)
2 5 Always 0
Enable Threshold
Comparison (ETC)
2 4 This bit is returned as set by the last LOG SELECT
command. The default is zero.
Threshold Met Criteria
Field (TMC)
2 3-2 This field is returned as set by the last LOG SELECT
command. As the default, both bits of this field are
returned set.
List Binary Information 2 1 Always 0
List Parameter (LP) 2 0 Always 0
The Parameter Length byte is the byte count of the parameter value that follows.
This length is not adjusted to match any truncation.
The Parameter Value bytes are the actual data requested according to the PC bits
of the CDB.
Write Error Counts (page 2)
Page 2 contains the Write Error counts, which are tabulations of the possible errors
(if any) encountered during writing to tape. The page 2 parameter codes for write
errors are listed in the following table.
Parameter Code Length Name
0002 2 Total rewrites
0003 3 Total errors corrected