Sony AIT-SDX470, Руководство по техническим характеристикам продукции

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READ 7. ATAPI Packet Command Specification
SONY AIT-1 Turbo drive SDX-470V series Ver.1.0 7-49
7.10. READ 08h
Bit
Byte
7 6 5 4 3 2 1 0
0 Operation Code (08h)
1 Reserved Reserved
(SILI)
Fixed
2 (MSB)
3
4
Transfer Length
(LSB)
5 Reserved
6 Reserved
7 Reserved
8 Reserved
9 Reserved
10 Reserved
11 Reserved
The READ command requests that the Device transfer one or more block(s) of data to the Host beginning with the
current block.
A
Fixed bit of ONE indicates the drive is reading in fixed block mode. A Fixed bit of ZERO indicates the drive is
reading in variable mode.
The
Transfer Length specifies the number of fixed-length blocks to be transferred, using the current block length
reported in the mode parameters block descriptor.
A
Transfer Length of zero indicates that no data shall be transferred. This condition shall not be considered an
error and the logical position shall not be changed but the Device shall start a read ahead mode of operation. The
DSC bit is reset (0) after this command is accepted and is set (1) when at least 52 blocks in the buffer are
available for the next READ command. Issuing a READ command when the DSC bit is reset will keep the ATA bus
busy (BSY=1) while the drive is reading the required data into buffer.
A successful READ command shall transfer the requested Transfer Length times the current block length in bytes.
Upon completion, the logical position shall be after the last block transferred ( EOP side).
If an incorrect length block is read, “Check Condition” status shall be returned and the ILI and Valid bits shall be
set to one in the sense data. Upon termination, the logical position shall be after the incorrect length block ( end-of-
partition side). The Information field shall be set to the difference (residue) of the requested Transfer Length
minus the actual number of blocks read (not including the incorrect length block).
If the Device encounters a filemark during a READ command, “Check Condition” status shall be returned and the
filemark and Valid bits shall be set to one in the sense data. The Sense Key shall be set to NO SENSE or
RECOVERED ERROR, as appropriate. Upon termination, the logical position shall be after the filemark (
end-of-
partition side). The Information field shall be set to the difference (residue) of the requested Transfer Length
minus the actual number of blocks read (not including the filemark).
Upon termination, the logical position shall be after the last block transferred or the block with an unrecoverable
read error
(end-of-partition side). The Information field shall be set to the difference (residue) of the requested
Transfer Length minus the actual number of blocks read.