Group 0 Command Descriptions for Printer Devices
10. Group 0 Command Descriptions for Printer Devices
The Group 0 commands for printer devices shall be as shown in Table 10-1.
Table 10-1
Group 0 Commands for Printer Devices
==============================================================================
Operation
Code Type Command Name Section
------------------------------------------------------------------------------
00H O TEST UNIT READY 7.1.1
01H V
02H V
03H M REQUEST SENSE 7.1.2
04H O FORMAT 10.1
05H V
06H V
07H V
08H V
09H V
0AH M PRINT 10.2
0BH O SLEW AND PRINT 10.3
0CH V
0DH V
0EH V
0FH V
10H O FLUSH BUFFER 10.4
11H V
12H E INQUIRY 7.1.3
13H V
14H O RECOVER BUFFERED DATA 10.5
15H O MODE SELECT 10.6
16H O RESERVE UNIT 10.7.1
17H O RELEASE UNIT 10.7.2
18H O COPY 7.1.4
19H V
1AH O MODE SENSE 10.8
1BH O STOP PRINT 10.9
1CH O RECEIVE DIAGNOSTIC RESULTS 7.1.5
1DH O SEND DIAGNOSTIC 7.1.6
1EH R
1FH R
==============================================================================
Key: M = Command implementation is mandatory.
E = Command implementation is required for SCSI devices that support
device-independent self-configuring software.
O = Command implementation is optional.
R = Operation code is reserved for future standardization.
V = Operation code is available for vendor unique commands.
10.1 FORMAT Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 04H
Table 10-2
FORMAT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Format Type |
-----|-----------------------------------------------------------------------|
2 | Transfer Length (MSB) |
-----|-----------------------------------------------------------------------|
3 | Transfer Length |
-----|-----------------------------------------------------------------------|
4 | Transfer Length (LSB) |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The FORMAT command (Table 10-2) provides a means for the initiator to
specify forms or fonts to printers that support programmable forms or fonts.
The format information sent is vendor unique since it is peripheral-device
specific.
The format type field specifies the type of format information to be
transferred from the initiator to the target. This field is defined as
follows:
DB(1) DB(0) Format Type
----- ----- -------------
0 0 Set Form
0 1 Set Font
1 0 Vendor Unique
1 1 Reserved
The transfer length specifies the length in bytes of format information that
shall be sent during the DATA OUT phase. A transfer length of zero indicates
that no format information shall be sent. This condition shall not be
considered as an error.
10.2 PRINT Command
Peripheral Device Type: Printer
Operation Code Type: Mandatory
Operation Code: 0AH
Table 10-3
PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Transfer Length (MSB) |
-----|-----------------------------------------------------------------------|
3 | Transfer Length |
-----|-----------------------------------------------------------------------|
4 | Transfer Length (LSB) |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The PRINT command (Table 10-3) transfers the specified number of bytes from
the initiator to the target to be printed. The data sent is application
dependent.
The transfer length specifies the length in bytes of data that shall be sent
during the DATA OUT phase. A transfer length of zero indicates that no data
shall be sent. This condition shall not be considered as an error.
10.3 SLEW AND PRINT Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 0BH
Table 10-4
SLEW AND PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Channel|
-----|-----------------------------------------------------------------------|
2 | Slew Value |
-----|-----------------------------------------------------------------------|
3 | Transfer Length (MSB) |
-----|-----------------------------------------------------------------------|
4 | Transfer Length (LSB) |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The SLEW AND PRINT command (Table 10-4) transfers the specified number of
bytes from the initiator to the target to be printed. The data sent is
application dependent. This command is provided for printers that do not
support forms control information imbedded within the print data.
The transfer length specifies the length in bytes of data that shall be sent
during the DATA OUT phase. A transfer length of zero indicates that no data
shall be sent. This condition shall not be considered as an error.
If the channel bit is zero, the slew value specifies the number of lines the
form shall be advanced before printing. A value of 255 indicates that the
form shall be advanced to the first line of the next form before printing. If
the channel bit is one, the slew value specifies the forms control channel
number to which the form shall be advanced prior to printing the data.
If the channel bit is one, and the channel option is not implemented, the
command shall be terminated with a CHECK CONDITION status and the sense key
shall be set to ILLEGAL REQUEST.
10.4 FLUSH BUFFER Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 10H
Table 10-5
FLUSH BUFFER Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The FLUSH BUFFER command (Table 10-5) provides a means for an initiator to
ensure that the data have been successfully printed prior to releasing the
peripheral device. This is useful for applications that wish to handle any
error or exception conditions (e.g., end-of-medium) prior to termination of
the application.
When all buffered data are actually printed the command shall be terminated
with a GOOD status. If it is not possible to finish printing all of the
buffered data (due to an error or exception condition on the peripheral
device), then this command shall be terminated with a CHECK CONDITION status
and the appropriate sense key.
10.5 RECOVER BUFFERED DATA Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 14H
Table 10-6
RECOVER BUFFERED DATA Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Transfer Length (MSB) |
-----|-----------------------------------------------------------------------|
3 | Transfer Length |
-----|-----------------------------------------------------------------------|
4 | Transfer Length (LSB) |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The RECOVER BUFFERED DATA command (Table 10-6) returns to the initiator the
data that has been sent to the target, but not yet printed.
This command is normally used only to recover from error or exception
conditions that make it impossible to print the buffered data. The order in
which the data is transferred from the target to the initiator is the same as
it was when the data was previously transferred using the PRINT command or
SLEW AND PRINT command. Data that is transferred by this command is deleted
from the target data buffer. One or more RECOVER BUFFERED DATA commands may
be used to return the unprinted buffered data.
If an attempt is made to recover more data than is contained in the buffer,
the command shall be terminated with a CHECK CONDITION status and the sense
key shall be set to NO SENSE. In addition, the EOM, the valid, and the ILI
bits in extended sense shall be set to one. The information bytes shall be
set to the difference (residue) between the transfer length and the actual
number of bytes returned.
The transfer length specifies the maximum length in bytes of data that shall
be transferred during the DATA IN phase. A transfer length of zero indicates
that no data shall be transferred. This condition shall not be considered as
an error.
10.6 MODE SELECT Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 15H
Table 10-7
MODE SELECT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Parameter List Length |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The MODE SELECT command (Table 10-7) provides a means for the initiator to
specify medium, logical unit, or peripheral device parameters to the target.
The parameter list length specifies the length in bytes of the MODE SELECT
parameter list that shall be transferred during the DATA OUT phase. A
parameter list length of zero indicates that no data shall be transferred.
This condition shall not be considered as an error. The MODE SELECT parameter
list (Table 10-8) contains a four-byte header, followed by the vendor unique
parameters, if any.
Table 10-8
MODE SELECT Parameter List
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Reserved |
-----|-----------------------------------------------------------------------|
1 | Reserved |
-----|-----------------------------------------------------------------------|
2 |Reserved| Buffered Mode | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
==============================================================================
| Vendor Unique Parameter(s) |
==============================================================================
0 _ n| Vendor Unique |
| Parameter Byte(s) |
==============================================================================
A buffered mode of zero indicates that the target shall not report a GOOD
status on PRINT commands or SLEW AND PRINT commands until the data are
actually printed. A buffered mode of one indicates that the target may report
a GOOD status on PRINT commands or SLEW AND PRINT commands as soon as the data
have been transferred to the SCSI device buffer. The data from one or more
commands may be buffered prior to printing. Buffered modes of 2H through 7H
are reserved.
10.7 RESERVE UNIT and RELEASE UNIT Commands
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 16H and 17H, respectively
Table 10-9
RESERVE UNIT and RELEASE UNIT Commands
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | 3rdPty | Third Party Device ID |Reserved|
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The RESERVE UNIT and RELEASE UNIT commands both use the command descriptor
block shown in Table 10-9.
10.7.1 RESERVE UNIT Command. The RESERVE UNIT command (Table 10-9,
operation code 16H) shall reserve the specified logical unit for the exclusive
use by the requesting initiator or, if third-party reservation option is
implemented, to another specified SCSI device.
The reservation shall remain in effect until superceded by another RESERVE
UNIT command from the initiator that made the reservation or until released by
a RELEASE UNIT command from the same initiator, or a BUS DEVICE RESET message
from any initiator, or a "hard" RESET condition. The occurrence of the last
two conditions is indicated by a sense key of UNIT ATTENTION on the next
command following the condition. It is not an error to issue this command to
a logical unit that is currently reserved to the requesting initiator.
If the logical unit is previously reserved by another initiator, then the
target shall either:
(1) return a RESERVATION CONFLICT status
(2) queue the reservation request and disconnect until all previously
queued reservations have been released. When the logical unit is available,
the target shall reconnect to perform the reservation
If, after honoring the reservation, any other initiator then subsequently
attempts to perform any command on the reserved logical unit other than a
RESERVE UNIT command, which may be queued, or a RELEASE UNIT command, which
shall be ignored, then the command shall be rejected with a RESERVATION
CONFLICT status.
The third-party reservation option for the RESERVE UNIT command allows an
initiator to reserve a logical unit for another SCSI device. This option is
intended for use in multiple-initiator systems that use the COPY command. Any
target that implements the third-party reservation option shall also implement
the third-party release option (see 10.7.2).
If the third-party (3rdPty) bit is zero, then the third-party reservation
option is not requested. If the 3rdPty bit is one and the third-party
reservation option is implemented, then the RESERVE UNIT command shall reserve
the specified logical unit for the SCSI device specified in the third-party
device ID field. The target shall preserve the reservation until superceded
by another RESERVE UNIT command from the initiator that made the reservation
or until released by the same initiator, by a BUS DEVICE RESET message from
any initiator, or by a "hard" RESET condition. The target shall ignore (i.e.,
return GOOD status) any attempt made by any other initiator to release the
reservation.
If the 3rdPty bit is one and the third-party reservation option is not
implemented, then the target shall reject the RESERVE UNIT command with a
CHECK CONDITION status and a sense key of ILLEGAL REQUEST.
An initiator that holds a current reservation may modify that reservation
(e.g., switch third-parties) by issuing another RESERVE UNIT command to the
same logical unit. The superceding RESERVE UNIT command shall release the
previous reservation state only when the new reservation is granted. A
superceding reservation takes priority over any previously queued reservation
request.
10.7.2 RELEASE UNIT Command. The RELEASE UNIT command (Table 10-9,
operation code 17H) shall release the logical unit if it is currently reserved
by the requesting initiator.
It is not an error to attempt to release a logical unit that is not
currently reserved to the requesting initiator. However, it shall not be
released if it is reserved by another initiator.
The third-party release option for the RELEASE UNIT command allows an
initiator to release a logical unit that was previously reserved using the
third-party reservation option (see 10.7.1). This option shall be implemented
if the third-party reservation option is implemented. This option is intended
for use in multiple-initiator systems that use the COPY command.
If the third-party (3rdPty) bit is zero, then the third-party release option
is not requested. If the 3rdPty bit is one and the target implements the
third-party release option, then the target shall release the specified
logical unit, but only if the reservation was made using the third-party
reservation option by the initiator that is requesting the release and for the
same SCSI device as specified in the third-party device ID field.
If the 3rdPty bit is one and the target does not implement the third-party
release option, then the target shall terminate the command with a CHECK
CONDITION status and the sense key shall be set to ILLEGAL REQUEST.
10.8 MODE SENSE Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 1AH
Table 10-10
MODE SENSE Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Allocation Length |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The MODE SENSE command (Table 10-10) provides a means for a target to report
its medium, logical unit, or peripheral device parameters to the initiator.
It is a complementary command to the MODE SELECT command.
The allocation length specifies the number of bytes that the initiator has
allocated for returned MODE SENSE data. An allocation length of zero
indicates that no MODE SENSE data shall be transferred. This condition shall
not be considered as an error. Any other value indicates the maximum number
of bytes that shall be transferred. The target shall terminate the DATA IN
phase when allocation length bytes have been transferred or when all available
MODE SENSE data have been transferred to the initiator, whichever is less.
The MODE SENSE data (Table 10-11) contains a four-byte header, followed the
vendor unique parameters, if any.
Table 10-11
MODE SENSE Data
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Sense Data Length |
-----|-----------------------------------------------------------------------|
1 | Reserved |
-----|-----------------------------------------------------------------------|
2 |Reserved| Buffered Mode | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
==============================================================================
| Vendor Unique Parameter(s) |
==============================================================================
0 _ n| Vendor Unique |
| Parameter Byte(s) |
==============================================================================
The sense data length specifies the length in bytes of the following MODE
SENSE data that is available to be transferred during the DATA IN phase. The
sense data length does not include itself.
A buffered mode of zero indicates that the target does not report a GOOD
status on PRINT commands or SLEW AND PRINT commands until the data are
actually printed. A buffered mode of one indicates that the target may report
a GOOD status on PRINT commands or SLEW AND PRINT commands as soon as the data
have been transferred to the SCSI device buffer. The data from one or more
commands may be buffered prior to printing. Buffered modes of 2H through 7H
are reserved.
10.9 STOP PRINT Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 1BH
Table 10-12
STOP PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Retain |
-----|-----------------------------------------------------------------------|
2 | Vendor Unique |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The STOP PRINT command (Table 10-12) is used to halt printing on buffered
devices in an orderly fashion.
A retain bit of zero requests that the target data buffer be discarded;
otherwise, the unprinted data is retained. The unprinted data may be
recovered by use of the RECOVER BUFFERED DATA command, if supported. A
subsequent PRINT command or SLEW AND PRINT command shall cause the remaining
unprinted and unrecovered data to be printed followed by the data transferred
by the subsequent command. The point at which printing is suspended by this
command is peripheral-device specific and is not defined by this standard.
The Group 0 commands for printer devices shall be as shown in Table 10-1.
Table 10-1
Group 0 Commands for Printer Devices
==============================================================================
Operation
Code Type Command Name Section
------------------------------------------------------------------------------
00H O TEST UNIT READY 7.1.1
01H V
02H V
03H M REQUEST SENSE 7.1.2
04H O FORMAT 10.1
05H V
06H V
07H V
08H V
09H V
0AH M PRINT 10.2
0BH O SLEW AND PRINT 10.3
0CH V
0DH V
0EH V
0FH V
10H O FLUSH BUFFER 10.4
11H V
12H E INQUIRY 7.1.3
13H V
14H O RECOVER BUFFERED DATA 10.5
15H O MODE SELECT 10.6
16H O RESERVE UNIT 10.7.1
17H O RELEASE UNIT 10.7.2
18H O COPY 7.1.4
19H V
1AH O MODE SENSE 10.8
1BH O STOP PRINT 10.9
1CH O RECEIVE DIAGNOSTIC RESULTS 7.1.5
1DH O SEND DIAGNOSTIC 7.1.6
1EH R
1FH R
==============================================================================
Key: M = Command implementation is mandatory.
E = Command implementation is required for SCSI devices that support
device-independent self-configuring software.
O = Command implementation is optional.
R = Operation code is reserved for future standardization.
V = Operation code is available for vendor unique commands.
10.1 FORMAT Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 04H
Table 10-2
FORMAT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Format Type |
-----|-----------------------------------------------------------------------|
2 | Transfer Length (MSB) |
-----|-----------------------------------------------------------------------|
3 | Transfer Length |
-----|-----------------------------------------------------------------------|
4 | Transfer Length (LSB) |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The FORMAT command (Table 10-2) provides a means for the initiator to
specify forms or fonts to printers that support programmable forms or fonts.
The format information sent is vendor unique since it is peripheral-device
specific.
The format type field specifies the type of format information to be
transferred from the initiator to the target. This field is defined as
follows:
DB(1) DB(0) Format Type
----- ----- -------------
0 0 Set Form
0 1 Set Font
1 0 Vendor Unique
1 1 Reserved
The transfer length specifies the length in bytes of format information that
shall be sent during the DATA OUT phase. A transfer length of zero indicates
that no format information shall be sent. This condition shall not be
considered as an error.
10.2 PRINT Command
Peripheral Device Type: Printer
Operation Code Type: Mandatory
Operation Code: 0AH
Table 10-3
PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Transfer Length (MSB) |
-----|-----------------------------------------------------------------------|
3 | Transfer Length |
-----|-----------------------------------------------------------------------|
4 | Transfer Length (LSB) |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The PRINT command (Table 10-3) transfers the specified number of bytes from
the initiator to the target to be printed. The data sent is application
dependent.
The transfer length specifies the length in bytes of data that shall be sent
during the DATA OUT phase. A transfer length of zero indicates that no data
shall be sent. This condition shall not be considered as an error.
10.3 SLEW AND PRINT Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 0BH
Table 10-4
SLEW AND PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Channel|
-----|-----------------------------------------------------------------------|
2 | Slew Value |
-----|-----------------------------------------------------------------------|
3 | Transfer Length (MSB) |
-----|-----------------------------------------------------------------------|
4 | Transfer Length (LSB) |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The SLEW AND PRINT command (Table 10-4) transfers the specified number of
bytes from the initiator to the target to be printed. The data sent is
application dependent. This command is provided for printers that do not
support forms control information imbedded within the print data.
The transfer length specifies the length in bytes of data that shall be sent
during the DATA OUT phase. A transfer length of zero indicates that no data
shall be sent. This condition shall not be considered as an error.
If the channel bit is zero, the slew value specifies the number of lines the
form shall be advanced before printing. A value of 255 indicates that the
form shall be advanced to the first line of the next form before printing. If
the channel bit is one, the slew value specifies the forms control channel
number to which the form shall be advanced prior to printing the data.
If the channel bit is one, and the channel option is not implemented, the
command shall be terminated with a CHECK CONDITION status and the sense key
shall be set to ILLEGAL REQUEST.
10.4 FLUSH BUFFER Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 10H
Table 10-5
FLUSH BUFFER Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The FLUSH BUFFER command (Table 10-5) provides a means for an initiator to
ensure that the data have been successfully printed prior to releasing the
peripheral device. This is useful for applications that wish to handle any
error or exception conditions (e.g., end-of-medium) prior to termination of
the application.
When all buffered data are actually printed the command shall be terminated
with a GOOD status. If it is not possible to finish printing all of the
buffered data (due to an error or exception condition on the peripheral
device), then this command shall be terminated with a CHECK CONDITION status
and the appropriate sense key.
10.5 RECOVER BUFFERED DATA Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 14H
Table 10-6
RECOVER BUFFERED DATA Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Transfer Length (MSB) |
-----|-----------------------------------------------------------------------|
3 | Transfer Length |
-----|-----------------------------------------------------------------------|
4 | Transfer Length (LSB) |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The RECOVER BUFFERED DATA command (Table 10-6) returns to the initiator the
data that has been sent to the target, but not yet printed.
This command is normally used only to recover from error or exception
conditions that make it impossible to print the buffered data. The order in
which the data is transferred from the target to the initiator is the same as
it was when the data was previously transferred using the PRINT command or
SLEW AND PRINT command. Data that is transferred by this command is deleted
from the target data buffer. One or more RECOVER BUFFERED DATA commands may
be used to return the unprinted buffered data.
If an attempt is made to recover more data than is contained in the buffer,
the command shall be terminated with a CHECK CONDITION status and the sense
key shall be set to NO SENSE. In addition, the EOM, the valid, and the ILI
bits in extended sense shall be set to one. The information bytes shall be
set to the difference (residue) between the transfer length and the actual
number of bytes returned.
The transfer length specifies the maximum length in bytes of data that shall
be transferred during the DATA IN phase. A transfer length of zero indicates
that no data shall be transferred. This condition shall not be considered as
an error.
10.6 MODE SELECT Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 15H
Table 10-7
MODE SELECT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Parameter List Length |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The MODE SELECT command (Table 10-7) provides a means for the initiator to
specify medium, logical unit, or peripheral device parameters to the target.
The parameter list length specifies the length in bytes of the MODE SELECT
parameter list that shall be transferred during the DATA OUT phase. A
parameter list length of zero indicates that no data shall be transferred.
This condition shall not be considered as an error. The MODE SELECT parameter
list (Table 10-8) contains a four-byte header, followed by the vendor unique
parameters, if any.
Table 10-8
MODE SELECT Parameter List
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Reserved |
-----|-----------------------------------------------------------------------|
1 | Reserved |
-----|-----------------------------------------------------------------------|
2 |Reserved| Buffered Mode | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
==============================================================================
| Vendor Unique Parameter(s) |
==============================================================================
0 _ n| Vendor Unique |
| Parameter Byte(s) |
==============================================================================
A buffered mode of zero indicates that the target shall not report a GOOD
status on PRINT commands or SLEW AND PRINT commands until the data are
actually printed. A buffered mode of one indicates that the target may report
a GOOD status on PRINT commands or SLEW AND PRINT commands as soon as the data
have been transferred to the SCSI device buffer. The data from one or more
commands may be buffered prior to printing. Buffered modes of 2H through 7H
are reserved.
10.7 RESERVE UNIT and RELEASE UNIT Commands
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 16H and 17H, respectively
Table 10-9
RESERVE UNIT and RELEASE UNIT Commands
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | 3rdPty | Third Party Device ID |Reserved|
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The RESERVE UNIT and RELEASE UNIT commands both use the command descriptor
block shown in Table 10-9.
10.7.1 RESERVE UNIT Command. The RESERVE UNIT command (Table 10-9,
operation code 16H) shall reserve the specified logical unit for the exclusive
use by the requesting initiator or, if third-party reservation option is
implemented, to another specified SCSI device.
The reservation shall remain in effect until superceded by another RESERVE
UNIT command from the initiator that made the reservation or until released by
a RELEASE UNIT command from the same initiator, or a BUS DEVICE RESET message
from any initiator, or a "hard" RESET condition. The occurrence of the last
two conditions is indicated by a sense key of UNIT ATTENTION on the next
command following the condition. It is not an error to issue this command to
a logical unit that is currently reserved to the requesting initiator.
If the logical unit is previously reserved by another initiator, then the
target shall either:
(1) return a RESERVATION CONFLICT status
(2) queue the reservation request and disconnect until all previously
queued reservations have been released. When the logical unit is available,
the target shall reconnect to perform the reservation
If, after honoring the reservation, any other initiator then subsequently
attempts to perform any command on the reserved logical unit other than a
RESERVE UNIT command, which may be queued, or a RELEASE UNIT command, which
shall be ignored, then the command shall be rejected with a RESERVATION
CONFLICT status.
The third-party reservation option for the RESERVE UNIT command allows an
initiator to reserve a logical unit for another SCSI device. This option is
intended for use in multiple-initiator systems that use the COPY command. Any
target that implements the third-party reservation option shall also implement
the third-party release option (see 10.7.2).
If the third-party (3rdPty) bit is zero, then the third-party reservation
option is not requested. If the 3rdPty bit is one and the third-party
reservation option is implemented, then the RESERVE UNIT command shall reserve
the specified logical unit for the SCSI device specified in the third-party
device ID field. The target shall preserve the reservation until superceded
by another RESERVE UNIT command from the initiator that made the reservation
or until released by the same initiator, by a BUS DEVICE RESET message from
any initiator, or by a "hard" RESET condition. The target shall ignore (i.e.,
return GOOD status) any attempt made by any other initiator to release the
reservation.
If the 3rdPty bit is one and the third-party reservation option is not
implemented, then the target shall reject the RESERVE UNIT command with a
CHECK CONDITION status and a sense key of ILLEGAL REQUEST.
An initiator that holds a current reservation may modify that reservation
(e.g., switch third-parties) by issuing another RESERVE UNIT command to the
same logical unit. The superceding RESERVE UNIT command shall release the
previous reservation state only when the new reservation is granted. A
superceding reservation takes priority over any previously queued reservation
request.
10.7.2 RELEASE UNIT Command. The RELEASE UNIT command (Table 10-9,
operation code 17H) shall release the logical unit if it is currently reserved
by the requesting initiator.
It is not an error to attempt to release a logical unit that is not
currently reserved to the requesting initiator. However, it shall not be
released if it is reserved by another initiator.
The third-party release option for the RELEASE UNIT command allows an
initiator to release a logical unit that was previously reserved using the
third-party reservation option (see 10.7.1). This option shall be implemented
if the third-party reservation option is implemented. This option is intended
for use in multiple-initiator systems that use the COPY command.
If the third-party (3rdPty) bit is zero, then the third-party release option
is not requested. If the 3rdPty bit is one and the target implements the
third-party release option, then the target shall release the specified
logical unit, but only if the reservation was made using the third-party
reservation option by the initiator that is requesting the release and for the
same SCSI device as specified in the third-party device ID field.
If the 3rdPty bit is one and the target does not implement the third-party
release option, then the target shall terminate the command with a CHECK
CONDITION status and the sense key shall be set to ILLEGAL REQUEST.
10.8 MODE SENSE Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 1AH
Table 10-10
MODE SENSE Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Allocation Length |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The MODE SENSE command (Table 10-10) provides a means for a target to report
its medium, logical unit, or peripheral device parameters to the initiator.
It is a complementary command to the MODE SELECT command.
The allocation length specifies the number of bytes that the initiator has
allocated for returned MODE SENSE data. An allocation length of zero
indicates that no MODE SENSE data shall be transferred. This condition shall
not be considered as an error. Any other value indicates the maximum number
of bytes that shall be transferred. The target shall terminate the DATA IN
phase when allocation length bytes have been transferred or when all available
MODE SENSE data have been transferred to the initiator, whichever is less.
The MODE SENSE data (Table 10-11) contains a four-byte header, followed the
vendor unique parameters, if any.
Table 10-11
MODE SENSE Data
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Sense Data Length |
-----|-----------------------------------------------------------------------|
1 | Reserved |
-----|-----------------------------------------------------------------------|
2 |Reserved| Buffered Mode | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
==============================================================================
| Vendor Unique Parameter(s) |
==============================================================================
0 _ n| Vendor Unique |
| Parameter Byte(s) |
==============================================================================
The sense data length specifies the length in bytes of the following MODE
SENSE data that is available to be transferred during the DATA IN phase. The
sense data length does not include itself.
A buffered mode of zero indicates that the target does not report a GOOD
status on PRINT commands or SLEW AND PRINT commands until the data are
actually printed. A buffered mode of one indicates that the target may report
a GOOD status on PRINT commands or SLEW AND PRINT commands as soon as the data
have been transferred to the SCSI device buffer. The data from one or more
commands may be buffered prior to printing. Buffered modes of 2H through 7H
are reserved.
10.9 STOP PRINT Command
Peripheral Device Type: Printer
Operation Code Type: Optional
Operation Code: 1BH
Table 10-12
STOP PRINT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Retain |
-----|-----------------------------------------------------------------------|
2 | Vendor Unique |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Vendor Unique | Reserved | Flag | Link |
==============================================================================
The STOP PRINT command (Table 10-12) is used to halt printing on buffered
devices in an orderly fashion.
A retain bit of zero requests that the target data buffer be discarded;
otherwise, the unprinted data is retained. The unprinted data may be
recovered by use of the RECOVER BUFFERED DATA command, if supported. A
subsequent PRINT command or SLEW AND PRINT command shall cause the remaining
unprinted and unrecovered data to be printed followed by the data transferred
by the subsequent command. The point at which printing is suspended by this
command is peripheral-device specific and is not defined by this standard.
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