Справочник Пользователя для Quantum Audio STT2401A
ATAPI Interface
Chapter 5
Seagate Travan 40 Product Manual
Page 51
MODE SELECT (Group 0, Op. Code 15)
The Host issues the MODE SELECT command to establish certain drive
parameters. These parameters are sent to the drive as data. The parameters
established by this command are not unique to the Initiator issuing the command. If a
second Initiator changes the parameters at any time, these new parameters are
used for all Hosts communicating with the drive. After accepting the MODE SELECT
parameters from the Initiator, the drive sets Unit Attention condition for all other
Initiators. The unit will accept this command when positioned anywhere on tape.
parameters. These parameters are sent to the drive as data. The parameters
established by this command are not unique to the Initiator issuing the command. If a
second Initiator changes the parameters at any time, these new parameters are
used for all Hosts communicating with the drive. After accepting the MODE SELECT
parameters from the Initiator, the drive sets Unit Attention condition for all other
Initiators. The unit will accept this command when positioned anywhere on tape.
CDB for MODE SELECT Command
Data Bits
Byte
7
6
5
4
3
2
1
0
Hex
0
0
0
0
1
0
1
0
1
15
1
0
0
0
PF
0
0
0
0
X0
2
0
0
0
0
0
0
0
0
00
3
4
4
Parameter List Length
XX
XX
XX
5
0
0
0
0
0
0
0
0
00
PF (Page Format): A PF bit of 1 indicates that MODE SELECT Parameters
following header and block descriptor are structured as pages of related parameters.
Only the following pages are valid: Page 01h (Error Recovery and Reporting
Parameter), Page 02h (Disconnect/Reconnect Control Parameters), Page 10h
(Device Configuration Parameters), Page 11h (Media Partition Parameters), Page
0Fh (Data Compression Parameters), and Page 20h (Forced Streaming
Parameters).
following header and block descriptor are structured as pages of related parameters.
Only the following pages are valid: Page 01h (Error Recovery and Reporting
Parameter), Page 02h (Disconnect/Reconnect Control Parameters), Page 10h
(Device Configuration Parameters), Page 11h (Media Partition Parameters), Page
0Fh (Data Compression Parameters), and Page 20h (Forced Streaming
Parameters).
Parameter List Length (PLL): This field specifies the number of bytes for the
Parameter List to be transferred from the Host. When 0, no bytes are transferred
and this is not considered an error. When greater than 12h and PF is set to 1, the
data following the Block Descriptor is in Page Format.
Parameter List to be transferred from the Host. When 0, no bytes are transferred
and this is not considered an error. When greater than 12h and PF is set to 1, the
data following the Block Descriptor is in Page Format.
NOTE: This field is 2 bytes in length.
Parameter List: The first four bytes of the Parameter List comprise the Header,
while the remaining bytes comprise the Block Descriptor.
while the remaining bytes comprise the Block Descriptor.
Header Data Bits
Byte
7
6
5
4
3
2
1
0
Hex
0
0
0
0
0
0
0
0
0
00
1
0
0
0
0
0
0
0
0
00
2
0
0
0
BUFM
Speed Code
XX
3
Block Descriptor Length
08
BUFM: The BUFM enables the Buffered Mode for WRITE commands. If BUFM is
set to 0, Buffered Mode is disabled for all WRITE commands, which do not terminate
and send a Good Sense until the last data block has been written onto the tape by
the drive. If BUFM is set to 1, Buffered Mode is enabled. WRITE commands
terminate and return a Good Status as soon as the Host places the last data block in
the buffer. If an error occurs while writing data after the command terminates, the
drive returns a Check Condition Status on the next command received from the
Host. The Host must then issue a REQUEST SENSE command to determine the
set to 0, Buffered Mode is disabled for all WRITE commands, which do not terminate
and send a Good Sense until the last data block has been written onto the tape by
the drive. If BUFM is set to 1, Buffered Mode is enabled. WRITE commands
terminate and return a Good Status as soon as the Host places the last data block in
the buffer. If an error occurs while writing data after the command terminates, the
drive returns a Check Condition Status on the next command received from the
Host. The Host must then issue a REQUEST SENSE command to determine the