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LOG SENSE
This information is contained within RAM in the Drive Controller. When a cassette is loaded, the contents of the
System Area are copied into this log. The log is updated as the tape is used and is copied back onto the System
Area when the cassette is unloaded (if the tape is Write enabled).
Note: The System Area only contains 'previous' and 'total' information – (when the cassette is unloaded, the
'current' values become the System Area 'previous' values).
The term 'current refers to information generated during the current load of the tape; 'previous' refers to
information generated during the last tape load; 'total' refers to information generated during the life of the tape
since it was first initialized including the current load.
Use: An estimate of reading and writing performance can be made by the ratios of 'RAW retries' to 'groups written'
and 'ECC-3 retries' to 'groups read'. An indication of tape degradation can be gained by comparing these ratios for
'current', 'previous' and 'total' entries.
Any attempt to change this page using LOG SELECT will result in a CHECK CONDITION with a Sense Key of
ILLEGAL REQUEST. The current cumulative values will be returned regardless of the Page Control field n the
LOG SENSE CDB.
7.6.7.
Tape Capacity Log Page
The tape Capacity Log Page is used to indicate the approximate capacity of the tape currently being used. The PC
field of the LOG SENSE command is ignored for this field.
When the AIT bit is set to ZERO in Mode Sense Page 31h, the 36 bytes of the log page shall be returned.
When the AIT bit is set to ONE, the 1028 bytes of the log page shall be returned.
The 36 bytes of the log page have the following format.
Bit
7
Byte
0
1
2
(MSB)
3
4
(MSB)
5
6
0 (DU)
1 (DS)
7
8
(MSB)
11
Tape Capacity Log Page Parameters:
Code Value: When AIT bit is set to ZERO in Mode Sense Page 31h
0001
Remaining capacity, partition 0 (kilobytes)
0002
Remaining capacity, partition 1 (kilobytes), For a single partition tape, it will be ZERO.
0003
Maximum capacity, partition 0 (kilobytes)
0004
Maximum capacity, partition 1 (kilobytes). For a single partition tape, it will be ZERO.
SONY AIT-1Turbo drive SDX-460V series Ver.1.0
Table 7-22: LOG PAGE Tape Capacity (31h)
6
5
4
Page Length (0020h when AIT bit=0
0400h when AIT bit=1))
0 (TSD)
0 (ETC)
Parameter Length (04h)
7. ATAPI Packet Command Specification
3
2
Page Code (31h)
Reserved
Parameter Code
0 (TMC)
Parameter Value
1
0
(LSB)
(LSB)
Reserved
0 (LP)
(LSB)
7-19
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