Write Command (0Ah) - Seagate SCSI Interface Product Manual

SCSI Interface Product Manual, Rev. J
5.49

Write command (0Ah)

The Write command (Table 171) requests that the drive write, to the medium, the data transferred by the initia-
tor.
Table 171: Write command (0Ah)
Bit 7
Byte
0 0
1 0
Logical Unit Number [1]
2 Logical Block Address
3 Logical Block Address (LSB)
4 Transfer Length [3]
5 0
Notes.
[1] The Logical Unit Number must be zero.
[2] The Logical Block Address specifies the logical block at which the write operation shall begin.
[3] The Transfer Length specifies the number of contiguous logical blocks of data to be transferred. A Transfer
Length of zero indicates that 256 logical blocks shall be transferred. Any other value indicates the number
of logical blocks that shall be transferred.
[4] See "Control byte," paragraph 4.2.6.
For systems that support disconnection, the drive disconnects when any internal error recovery procedure is
required, or the data transfer with the initiator is interrupted for more than 1 millisecond, or if the drive's internal
data buffer is full. After a disconnect, the drive reconnects depending on the value of the Buffer Empty Ratio in
Page 2 of Mode Select Data (see Section 5.10).
The initiator must send requested write data to the drive until the drive sends Completion status during a Sta-
tus phase or until the initiator Resets/Aborts the command or clears the queue.
Note. The drive may disconnect and reconnect while executing this command.
Sense Data is valid after this command is executed and Completion status is sent (refer to the Read command
description in Section 5.19).
If the RCD bit is set to zero on the Caching Mode page 08h (cache is enabled), the data that is written by this
command remains in the cache buffer, if no write errors are encountered. This allows a Read command to
access the same data from the cache buffer instead of accessing the media, if the same LBA is requested by
the Read command.
This command is terminated with a Reservation Conflict status and no data is written if any reservation access
conflict (see Section 5.35) exists.
If any of the following conditions occur, this command is terminated with a Check Condition status, and if
extended sense is implemented, the Sense Key is set as indicated in the following table. This table does not
provide an exhaustive enumeration of all conditions that may cause the Check Condition status.
Condition
Invalid Logical Block Address
Target reset since last command from this initiator
Note. The extended sense Information Bytes shall be set to the Logical Block Address of the first invalid
address.
6 5
0 0
0 0
0 0
4 3
0 1
Logical Block Address (MSB) [2]
0 0
Sense Key
Volume Overflow (see note below)
Unit Attention
2 1
0 1
0 Flag [4] Link [4]
213
0
0