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SCSI Commands: 21BLOG SENSE
Page
74
3.9.16
Data Compression Log Page (32h)
The Data Compression Log Page records compression information. The parameters
on this page can be reset to zero with the LOG SELECT command
Page Code
Page Length
32h 4Ch
Parameter Description
Length
0
Read compression ratio in percent
2
1
Write compression ratio in percent
2
2
Millions of total bytes transferred to host
4
3
Remaining bytes of total bytes transferred to host
4
4
Millions of total bytes read from tape
4
5
Remaining bytes of total bytes read from tape
4
6
Millions of total bytes transferred from host
4
7
Remaining bytes of total bytes transferred from host
4
8
Millions of total bytes written to tape
4
9
Remaining bytes of total bytes written to tape
4
Parameters 2 through 9 occur as pairs each of which represents a total number of
bytes (i.e., total number of bytes transferred to host as with Parameter 2 and 3 pair.)
The first four-byte parameter of a pair represents millions of bytes (10
6
.) The second
four-byte parameter of a pair represents the difference between the millions of bytes
and the total number of bytes as a positive number in the range of 0 to 999,999.
Thus the total number of bytes is the first four-byte parameter in bytes plus the
second four-byte parameter. Parameters 0 and 1are in percent, i.e. 200 represents
200% compression. Compression ratios will be most accurate after 10
8
bytes have
been read or written.
3.9.17
Error Events Log Page (33h)
The Error Events Log Page records anomalies in the operation of the drive. These
may be due to media errors or other causes. Each parameter records one or more
successive events of the same type; with a repeat count indicating how many times
that particular event happened. Up to sixteen parameters are reported; each one
has a different parameter code, from zero to fifteen.
Events are recorded in non-volatile memory and can be retrieved even after the
drive has been reset or power cycled. If more that sixteen different events are
recorded during the lifetime of the drive, then the oldest events will be overwritten. If
fewer than sixteen different events have been recorded during the lifetime of the
drive, then fewer than sixteen parameters will be reported.
Page Code
Page Length
33h
82 x number of parameters reported (1312 or 520h maximum)
Summary of Contents for LTO 4
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