Maxtor 10K III manual 148, Read Long Command Descriptor Block-Data Format

SCSI Description

￿￿￿￿4'#&The￿.READ10)￿LONG%QOOCPFcommand￿￿￿'Jis￿used in conjunction with the WRITE LONG command to allow the initiator to issue raw reads and writes of physical data blocks, but address them as logical blocks with an assumed sector length of 512 bytes. These two commands are used to verify the correction capability of the drive’s ECC and to create a known kind and location to verify the drive’s recovery and bad sector handling policies. The data format and field descriptions are shown in Table 5-146and Table 5-147respectively.

READ LONG Command Descriptor Block-Data Format

	$[VG0$KV		￿		￿￿	Operation￿		Code￿(3Eh)	￿	￿	￿
	1					Reserved				Correct	RelAdr
	2 - 5					Logical Block Address
	6						Reserved
	7 - 8					Byte Transfer Length (562)
	9						Control
				READ LONG Command Descriptor Block-Field Descriptions
		When the value in this field is 1, the drive corrects the data by the ECC before trans-
		ferring it to the initiator. When the value is 0, the drive does not perform ECC cor-
Correct(KGNF		rection on the data.					&GUETKRVKQP
		NOTE: This bit, not the DCR bit of the Read Recovery page, governs the effect of
		error correction for the READ LONG command.
RelAdr		Relative addressing is not supported by the drive. This value must be 0.
Table5-146
Logical Block Ad- Specifies the logical sector to read.
dress
		Must be 562. This value reflects the number of bytes spanned by the ECC, including
		the ECC itself, rounded up to the next word (this is easiest understood in bits: 4096
Byte Transfer		data bits + 1 force error bit + 15 Logical Block Address bits + 16 cross check bits
Length		+ 2 pad bits + 360 ECC bits + 6 pad bits that are not written to media but are only
		needed for transfer = 4496 bits or 562 bytes). Any other value in this field results
		in a CHECK CONDITION status and the appropriate sense data.

5-148shows the format of the data that is returned during the READ LONG Command's data-in buffer transfer. The returned data always consists of 512 bytes of

data, followed by a two LBA bytes, two EDC bytes, and 46 ECC-related bytes.
Table5-147			READ LONG Command-Returned Data
0 - 511				Data (512 Bytes)
$512[VG- 513$KV	￿	￿	Logical￿Block Address￿		Bits ￿+ Force Error￿	Bit	￿	￿
	Table5-148				Maxtor Atlas 10K III			5-117