Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E 171
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Notes.
[1] LUN must be zero.
[2] A relative address (RelAdr) bit of one indicates that the logical block address
[3] field is a two’s complement displacement. This negative or positive displacement is to be added to the
logical block address last accessed on the logical unit to form the logical block address for this command.
This feature is only available when linking commands. The feature requires that a previous command in
the linked group have accessed a block of data on the logical unit.
A RelAdr bit of zero indicates that the logical block address field specifies the first logical block of the
range of logical blocks to be operated on by this command.
[4] A Partial Medium Indicator (PMI) bit of zero indicates the information returned in the Read Capacity data
shall be the Logical Block Address and Block Length (in bytes) of the last logical block of the logical unit*.
The Logical Block Address in the Command Descriptor Block shall be set to zero for this option.
A PMI bit of one indicates the information returned shall be the Logical Block Address and Block Length
(in bytes) of the last Logical Block Address after which a substantial delay (defined as approximately 1
millisecond for the typical disc drive) in data transfer is encountered. This returned Logical Block Address
shall be greater than or equal to the Logical Block Address specified in the Command Descriptor Block.
This reported Logical Block Address is the last block prior to a cylinder boundary.
[5] See “Control Byte” paragraph 4.2.6.
In response to the Read Capacity Command, the drive returns 8 bytes of Read Capacity Data to the host.
The contents of the 8 bytes are listed in Table 5.2.2-2a.
Table 5.2.2-2a. Read Capacity Data
Byte
Description
0
LOGICAL BLOCK ADDRESS (MSB)
1
LOGICAL BLOCK ADDRESS
2
LOGICAL BLOCK ADDRESS
3
LOGICAL BLOCK ADDRESS (LSB)
4
BLOCK LENGTH (MSB)
5
BLOCK LENGTH
6
BLOCK LENGTH
7
BLOCK LENGTH (LSB)
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* This value is the same for all drives of the same model number, sector size and sparing scheme. It is the
same regardless of the number of defective blocks the drive has.