Seagate Medalist ST31082A, Руководство по эксплуатации продукта

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Chapter 7 Command Set
Page 58 ST3636A/ST31082A/ST31276A
If a non-correctable data error occurs during a multiple sector read, the read
will terminate at the sector where the error occurs. The Task File Registers will
contain the cylinder, head, and sector number of the sector where the error
occurred. The host may then read the Task File to determine what error has
occurred, and on which sector.
A Read Long may be executed by setting the long bit in command code. The
Read Long command returns the data and the ECC bytes contained in the
data field of the desired sector. During a read long, the drive does not check the
ECC bytes to determine there has been any type of data error. Data bytes are
16-bit transfers and ECC bytes are 8-bit transfers.
Read Sector Buffer
Command Number: E4 hex
Description: The Read Buffer command allows the host to read the current
contents of the drive’s sector buffer. Only the Command register is valid for this
command.
When this command is issued, the drive will set BSY, set up the sector buffer
for a read operation, set DRQ, reset BSY, and generate an interrupt. The host
may then read up to 512 bytes of data from the buffer.
Read Verify Sectors
Command Number: 4x hex
Description: This command functions similarly to the Read Sectors
command, except that no data is transferred to the host and at completion of
the command. There are two versions of this command, as shown below:
Command Number: Command Name
40 hex Read Verify with retries
41 hex
Read Verify without retries
The drive remains Busy until all data is verified. If Look Ahead Read is active,
the Verify command will also work the same as when a Read is performed.