31 read long command, Read long command – Seagate Fibre Channel Interface User Manual
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Fibre Channel Interface Manual, Rev. D
12.31
Read Long command
The Read Long command requests that the target transfer data to the initiator. The data passed during the
Read Long command shall include the data bytes and the ECC bytes recorded on the medium. The most
recent data written, or to be written, in the addressed logical block shall be returned. Read Long is independent
of the Read-Write Error Recovery mode page but does allow retries.
Field definitions (listed alphabetically)
Byte Transfer Length
The number of bytes of data that will be transferred. A transfer length of zero indicates that no bytes are transferred. This
condition is not considered an error.
The byte transfer length requested must be equal to the current block size plus all ECC bytes for a data transfer to occur. If
an incorrect number of bytes is stated in the command block, this command terminates with a Check Condition status. The
correct number of bytes can be determined from the information returned in the extended sense data bytes after issuing the
Request Sense command. The Request Sense command results in the Illegal Field In CDB condition with the Illegal
Request sense key. The extended sense ILI bit is set. The extended sense information bytes contain the difference (resi-
due) of the requested length minus the actual length (in bytes). (Negative values are indicated by two’s complement nota-
tion.)
Control
See Control Bytes in Section 11.2.1.6.
CORRECT (Corrected)
0
A logical block will be read without any correction made by the target.
1
The data will be corrected by ECC, if necessary, before being transferred to the initiator.
If the DCR bit of the Read-Write Error Recovery page is equal to 1 and the CORRCT bit equals 1, the Read Long command
terminates with Check Condition status and the sense key is set to Illegal Request with an additional sense code of Invalid
Field in CDB.
Logical Block Address
The logical block at which the read operation will occur. The most recent data written in the addressed logical block is
returned.
RelAdr (Relative Address)
This function is not supported by drives described in this manual.
Table 186: Read Long command (3Eh)
Bit
Byte
7
6
5
4
3
2
1
0
0
0
0
1
1
1
1
1
0
1
0
0
0
0
0
0
CORRECT
RelAdr
2
Logical Block Address (MSB)
3
Logical Block Address
4
Logical Block Address
5
Logical Block Address (LSB)
6
0
0
0
0
0
0
0
0
7
Byte Transfer Length (MSB)
8
Byte Transfer Length (LSB)
9
Control
3Eh
Table
number