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4.1.3
READ CAPACITY (25)
Bit
7
Byte
0
1
0
2
3
4
5
6
0
7
0
8
0
9
0
This command transfers information related to the disk drive's capacity and the data block size
to the INIT.
When bit 0 "PMI (partial medium indicator)" of CDB byte 8 is "0," the logical block address
and block length (byte length) of the final data block which is accessible in the disk drive (user
space) are transferred to the INIT. At this time, the "Logical Block address" field in the CDB
must specify zero.
When the "PMI" bit is "1," the logical block address and block length (byte length) of data
blocks which satisfy either of the following conditions is transferred to the INIT.
•
The data block on the cylinder where the specified block exists, which is just before the
block where the first alternate sector processing (not including defective block sector slip
processing) is implemented.
implemented in the specified block, the data block specified in the CDB.
•
When no alternate sector processed data block exists in the cylinder where the specified
block exists, the last data block in that cylinder.
4 - 10
6
5
4
X'25'
0
0
0
Logical Block Address (MSB)
Logical Block Address
Logical Block Address
Logical Block Address (LSB)
0
0
0
0
0
0
0
0
0
0
0
0
However, when alternate sector processing is being
C141-E054-02EN
3
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
PMI
0
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