Page
40
LTO SCSI Interface Manual
Disable
Update
(DU)
2
7
0 = Enables update of accumulated value when the corresponding
event occurs.
1 = Disables update of all accumulated values within a log page
when the corresponding event occurs. The drive sets this bit to
indicate that the accumulated value of the parameter has
reached its maximum value so that the drive can no longer in-
crement any Parameter Values.
Disable
Save (DS)
2
6
Always 1, indicating that the drive does not support Save Page in
Log Sense and Log Select.
Parameter
Length
3
n – 3, indicating the length of the Parameter Value.
Parameter
Value
4 - n
Actual data.
Reserved
Always 0.
The parameter header contains a two-byte parameter code to identify the parameter,
a Parameter Control byte, and a parameter length byte.
All of the bits in byte 2 of the Log Parameter are collectively referred to as the
Parameter Control byte. The Parameter Control byte specifies counter controls.
The host specifies the Parameter Control byte to control
•
Whether or not a counter is enabled.
•
Whether or not a Check Condition is generated when a counter is incremented,
and if so, how the Check Condition is generated.
Each Log Parameter contains only one control byte. This control byte is shared
between the threshold and accumulated parameters. The Log Sense data reflects
the current setting of the control byte for the parameter.
There are several logs of different formats that allow you to retrieve different drive
parameters. The following logs are supported:
Log
See Page
Supported Log Pages Log
45
Write Error Counters Log
46
Read Error Counters Log
47
Sequential Access Device Log
47
Tape Alert Log
47
Tape Usage Log
48
Tape Capacity Log
48
Data Compression Log
49
Maximum Counts
The maximum value of each counter depends on the size of the counter in bytes.
When the maximum count is reached, the DU bit in the Parameter Control byte for
the counter is set to 1 for the Log Sense data indicating that the parameter is no
longer to be updated by the drive because the maximum count has been reached
and if RLEC (Report Log Exception Condition) bit in Mode Page 0Ah (Control Mode
page) is set to 1, Recovered Error/Log Counter at Maximum (01/5B/02) is returned to
host to inform of the log exception. Bytes 15-17 of the Request Sense data specify
the page, MSB and LSB of the Parameter Code respectively, which caused the Log
Exception.
