Read Long Command Descriptor Block-Data Format; Read Long Command Descriptor Block-Field Descriptions; Read Long Command-Returned Data - Maxtor ATLAS 10K III Product Manual

  
The READ LONG command is 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 5-146 and
Table 5-147 respectively.
T a b l e 5 - 1 4 6 READ LONG Command Descriptor Block-Data Format
$ K V
$ [ V G
0
1
2 - 5
6
7 - 8
9
T a b l e 5 - 1 4 7 READ LONG Command Descriptor Block-Field Descriptions
( K G N F
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-
rection on the data.
Correct
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.
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.
Table 5-148 shows 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.
T a b l e 5 - 1 4 8 READ LONG Command-Returned Data
$ K V
$ [ V G
0 - 511
512 - 513
  
Reserved
Byte Transfer Length (562)
  
Logical Block Address Bits + Force Error Bit
 
Operation Code (3Eh)
Logical Block Address
Reserved
Control
& G U E T K R V K Q P
 
Data (512 Bytes)
Maxtor Atlas 10K III
SCSI Description
  
Correct RelAdr
  
5-117