Read Capacity Command (25H) - Maxtor ATLAS 10K IV User Manual

5.23

READ CAPACITY Command (25h)

The READ CAPACITY command reports formatted capacity and track-boundary
information. The data format and field descriptions are shown in Table 5-127 and
Table 5-128 respectively.
Table 5-127
Bit
Byte
0
1
2 - 5
6 - 7
8
9
Table 5-128
Field
RelAdr
Logical Block Address
PMI
Table 5-129 shows the READ CAPACITY Returned Data - Data Format that will be
sent during the data-in buffer transfer for the command. Refer to the PMI description
in Table 5-128 for a description of these data fields.
Table 5-129
Bit
Byte
0 - 3
4 - 7
READ CAPACITY Command-Data Format
7 6 5
READ CAPACITY Command-Field Descriptions
Relative Addressing is not supported by the drive; the field must be 0.
Used in conjunction with the PMI bit. Must be 0 when the PMI bit is 0.
Partial Media Indicator. When the value in the field is 0, the Returned Log-
ical Block Address (Table 5-129) is that of the last logical sector of the log-
ical unit.
When the value is 1, the Returned Logical Block Address is that of the last
sector on the same cylinder as the Logical Block Address supplied in the
Command Descriptor Block's LBA field. That is, the Returned Logical
Block Address is that of the Logical Block Address before a substantial de-
lay in data transfer will be encountered).
In either case, Block Length in Bytes (Table 5-129) is the unit's logical sec-
tor size, as determined by the Block Length field in the Mode parameter
Block Descriptor.
READ CAPACITY Returned Data-Data Format
7 6 5
Returned Logical Block Address
4 3
Operation Code (25h)
Reserved
Logical Block Address
Reserved
Reserved
Control
Description
4 3
Block Length in Bytes
Maxtor Atlas 10K IV
SCSI Description
2 1 0
RelAdr
PMI
2 1 0
5-93