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7. All Device Types
7.1. Model for All Device Types
This model describes some of the general characteristics expected of most
SCSI devices. It is not intended to define any requirements nor is it
intended to alter any requirements defined elsewhere in this standard.
Section 6 of this standard also contains model information pertaining to all
device types.
7.1.1. SCSI Addresses
There are two levels of addresses within the SCSI architecture: the SCSI
device address and the logical unit number or target routine number.
7.1.1.1. SCSI Device Address
SCSI devices occupy (i.e., respond to) one address on the SCSI bus.
Generally the SCSI device provides a means (e.g., switches, jumpers) to select
one of the eight available addresses (0 through 7). This address is used
during bus arbitration and selection or reselection of SCSI devices. Each
device on the SCSI bus is assigned an unique address.
Normally, the SCSI device address is set when the system is configured and
it remains static thereafter. Some systems and devices provide vendor-
specific means to alter this address at other times.
7.1.1.2. Logical Units
Each target has one or more logical units, beginning with logical unit zero.
There is a maximum of eight logical units. These logical units are usually
mapped directly to peripheral devices, but they may be a portion of a
peripheral device or may comprise multiple peripheral devices.
An initiator can determine whether a target implements a logical unit by
issuing an INQUIRY command and examining the returned peripheral qualifier and
peripheral device type.
The concept of a logical unit is not defined for an initiator. (An SCSI
device may implement both the initiator role and the target role. In this
case logical unit(s) are defined only for the target role.)
7.1.1.3. Target Routines
An optional feature of the SCSI architecture permits each target to have one
or more target routines, beginning with target routine number zero. There is
a maximum of eight target routines. These target routines are processes that
execute directly on the target and are not associated with a particular
logical unit or peripheral device. Target routines are addressed using the
LUNTAR bit of the IDENTIFY message (see 5.6.7).
Target routines are principally intended to return information about the
target and the only valid commands are INQUIRY and REQUEST SENSE.
7.1.2. Commands Implemented by all SCSI Devices
This standard defines four commands that all SCSI-2 targets implement:
INQUIRY, REQUEST SENSE, SEND DIAGNOSTIC, and TEST UNIT READY. These commands
are used to configure the system, to test targets, and to return important
information concerning errors and exception conditions.
7.1.2.1. Using the INQUIRY Command
The INQUIRY command may be used by a system to determine the configuration
of the SCSI bus. Target devices respond with information that includes their
type and standard level and may include the vendor's identification, model
number and other useful information. It is recommended that SCSI targets be
capable of returning this information (or whatever part of it that is
available) upon completing power-on initialization. An SCSI device may take
longer to get certain portions of this information, especially if it retrieves
the information from the medium.
7.1.2.2. Using the REQUEST SENSE Command
Whenever a contingent allegiance condition (6.6) is established, the
initiator that received the error should issue a REQUEST SENSE command to
receive the sense data describing what caused the contingent allegiance
condition. If the initiator issues some other command, the sense data is
lost.
7.1.2.3. Using the SEND DIAGNOSTIC Command
The SEND DIAGNOSTIC command provides a means to request the target to
perform a self test. While the test is target specific, the means of
requesting the test is standardized and the response is simply GOOD status if
all is well or CHECK CONDITION status if the test fails.
The SEND DIAGNOSTIC command also provides other powerful features when used
in conjunction with the RECEIVE DIAGNOSTIC RESULTS command, but this
capability is optional.
7.1.2.4. Using the TEST UNIT READY Command
The TEST UNIT READY command is useful in that it allows an initiator to poll
a logical unit until it is ready without the need to allocate space for
returned data. It is especially useful to check cartridge status of logical
units with removable media. Targets are expected to respond promptly to
indicate the current status of the device (i.e., a target should avoid lengthy
disconnections in an attempt to respond with GOOD status).
7.2. Commands for All Device Types
The operation codes for commands that apply to all device types are listed
in Table 7-1.
Table 7-1: Commands for All Device Types
==============================================================================
Operation
Command Name Code Type Section
------------------------------------------------------------------------------
CHANGE DEFINITION 40h O 7.2.1
COMPARE 39h O 7.2.2
COPY 18h O 7.2.3
COPY AND VERIFY 3Ah O 7.2.4
INQUIRY 12h M 7.2.5
LOG SELECT 4Ch O 7.2.6
LOG SENSE 4Dh O 7.2.7
MODE SELECT(6) 15h Z 7.2.8
MODE SELECT(10) 55h Z 7.2.9
MODE SENSE(6) 1Ah Z 7.2.10
MODE SENSE(10) 5Ah Z 7.2.11
READ BUFFER 3Ch O 7.2.12
RECEIVE DIAGNOSTIC RESULTS 1Ch O 7.2.13
REQUEST SENSE 03h M 7.2.14
SEND DIAGNOSTIC 1Dh O 7.2.15
TEST UNIT READY 00h M 7.2.16
WRITE BUFFER 3Bh O 7.2.17
==============================================================================
Key: M = Command implementation is mandatory.
O = Command implementation is optional.
Z = Command implementation is device type specific.
7.2.1. CHANGE DEFINITION Command
Table 7-2: CHANGE DEFINITION Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (40h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved | Save |
-----|-----------------------------------------------------------------------|
3 |Reserved| Definition Parameter |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | Reserved |
-----|-----------------------------------------------------------------------|
8 | Parameter Data Length |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The CHANGE DEFINITION command (Table 7-2) modifies the operating definition
of the selected logical unit or target with respect to commands from the
selecting initiator or for all initiators.
A save control bit (Save) of zero indicates that the target shall not save
the operating definition. A Save bit of one indicates that the target shall
save the operating definition to non-volatile memory.
The definition parameter field is defined in Table 7-3.
Table 7-3: Definition Parameter Field
=================================================
Value Meaning of Definition Parameter
----- ---------------------------------------
00h Use Current Operating Definition
01h SCSI-1 Operating Definition
02h CCS Operating Definition
03h SCSI-2 Operating Definition
04-3Fh Reserved
40-7Fh Vendor Specific
=================================================
IMPLEMENTORS NOTE: The current operating definition parameter values
establish operating definitions compatible with the appropriate SCSI
specification. Vendor-specific values are available for those applications
where more complex operation definition changes are required. Definitions
supported by a device are returned in the implemented operating definition
page (see 7.3.4.3).
The parameter data length field specifies the length in bytes of the
parameter data that shall be transferred from the initiator to the target. A
parameter data length of zero indicates that no data shall be transferred.
This condition shall not be considered as an error. Parameter data lengths
greater than zero indicate the number of bytes of parameter data that shall be
transferred.
The parameter data is vendor specific.
IMPLEMENTORS NOTE: The parameter data may be used to specify a password to
validate an operating definition change.
The CHANGE DEFINITION command causes one of the operating definition
modifications listed below:
(1) Change the operating definition of a logical unit relative to the
initiator that issued the command. In this case, the target is capable of
maintaining an unique operating definition for each logical unit relative to
each initiator in the system.
(2) Change the operating definition of the target relative to the initiator
that issued the command. In this case, the target is capable of maintaining
an unique operating definition, for each initiator in the system, that applies
to all logical units of the target.
(3) The operating definition of a logical unit relative to all initiators in
the system. In this case, the target is capable of maintaining an unique
operating definition for each logical unit relative to all initiators in the
system.
(4) The operating definition of the target relative to all initiators in the
system. In this case, the target is capable of maintaining only one operating
definition.
IMPLEMENTORS NOTE:
(1) This standard does not provide a direct means to determine which of the
above four methods has been implemented by the target. An indirect means of
determining which method is implemented exists in that the target is
required to inform affected initiators of operating definition changes via
the unit attention condition.
(2) Cases (3) and (4), above, may result in incompatibilities if there are
other initiators in the system operated below the SCSI-2 level.
The operating definition is modified after successful completion of the
command. A target shall consider the command successfully completed when it
detects the assertion of the ACK signal for the COMMAND COMPLETE message. The
initiator should verify the new operating definition by issuing an INQUIRY
command requesting the implemented operating definition page (see Table 7-75).
It is permissible for an SCSI-2 device that has its definition changed to an
SCSI-1 device to accept a CHANGE DEFINITION command.
IMPLEMENTORS NOTE: The method of changing the operating definition is
implementation dependent. Some implementations may require the target's
operating mode be re-initialized as if a power-up or hard-reset had
occurred. Other implementations may modify only those operating definitions
that are affected by the CHANGE DEFINITION command.
If the CHANGE DEFINITION command is not executed successfully for any
reason, the operating definition shall remain the same as it was before the
CHANGE DEFINITION command was attempted. If it is impossible to return to the
previous operating definition, an unit attention condition shall be generated
by the target.
IMPLEMENTORS NOTE: The present operating definition of the target may
always be interrogated through the INQUIRY command. When an SCSI-2 target
has its operating definition changed to CCS or SCSI-1, certain changes are
needed to promote compatibility with pre-existing SCSI-1 initiators. The
recommended changes are as follows:
(1) The target should not initiate selections to other SCSI devices to
determine if any initiators support AEN. The target should assume that none
are capable of receiving AEN and not issue an AEN.
(2) The target should not generate extended contigent allegiance conditions
by issuing an INITIATE RECOVERY message.
(3) If a REQUEST SENSE command with an allocation length of zero is
received, the target should return four bytes of sense data.
(4) If an INQUIRY command is received, the returned data should have
appropriate values in the ANSI version and response data format fields. The
features supported bits should be zero.
(5) A change in the operating definition may change the vendor identifier,
the device type, the device model, the SCSI implementation level, the
command set, and any other operating characteristics.
After a power-on condition or a hard RESET condition, the target shall set
its initial operating definition to the last saved value, if saving is
implemented, or its default value, if saving is not implemented.
7.2.2. COMPARE Command
Table 7-4: COMPARE Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (39h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Pad |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | (MSB) |
- - -|- - Parameter List Length - -|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | |
- - -|- - Reserved - -|
8 | |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The COMPARE command (Table 7-4) provides the means to compare data from one
logical unit with another or the same logical unit in a manner similar to the
COPY command.
This command functions in the same manner as the COPY command, except that
the data from the source is compared on a byte-by-byte basis with the data
from the destination. The parameter list transferred to the target is the
same as for the COPY command. This parameter list contains the information to
identify the logical units involved in the comparison and the length of the
comparison. (See 7.2.3 for additional information about the COPY command.)
If the comparison is unsuccessful, the command shall be terminated with
CHECK CONDITION status and the sense key shall be set to MISCOMPARE. The
remaining fields in the sense data shall be set as documented in the COPY
command.
7.2.3. COPY Command
Table 7-5: COPY Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (18h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Pad |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
- - -|- - Parameter List Length - -|
4 | (LSB) |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The COPY command (Table 7-5) provides a means to copy data from one logical
unit to another or the same logical unit. The logical unit that receives and
performs the COPY command is called the copy manager. The copy manager is
responsible for copying data from a logical unit (source device) to a logical
unit (destination device). These logical units may reside on different SCSI
devices or the same SCSI device (in fact all three may be the same logical
unit). Some SCSI devices that implement this command may not support copies
to or from another SCSI device, or may not support third party copies (i.e.,
both the source and the destination logical units reside on other SCSI
devices).
The pad bit (7.2.3.7) is used in conjunction with the Cat bit (7.2.3.7) in
the segment descriptors to define what action should be taken when a segment
of the copy does not fit exactly into an integer number of destination blocks.
The parameter list length field specifies the length in bytes of the
parameters that shall be sent during the DATA OUT phase of the command. A
parameter list length of zero indicates that no data shall be transferred.
This condition shall not be considered as an error.
The COPY parameter list (Table 7-6) begins with a four-byte header that
contains the COPY function code and priority. Following the header is one or
more segment descriptors.
Table 7-6: COPY Parameter List
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | COPY Function Code | Priority |
-----|-----------------------------------------------------------------------|
1 | Vendor Specific |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
==============================================================================
| Segment Descriptor(s) |
==============================================================================
0 - | Segment Descriptor 0 |
xx | (See specific table for length.) |
-----|-----------------------------------------------------------------------|
| . |
| . |
| . |
-----|-----------------------------------------------------------------------|
0 - | Segment Descriptor n |
xx | (See specific table for length.) |
==============================================================================
The COPY function code field defines a specific format for the segment
descriptors. The COPY function codes are defined in Table 7-7. A target need
not support all function codes for its device type.
The priority field of the COPY parameter list establishes the relative
priority of this COPY command to other commands being executed by the same
target. All other commands are assumed to have a priority of 1. Priority 0
is the highest priority with increasing values indicating lower priorities.
The segment descriptor formats are determined by the COPY function code.
The segment descriptor format used for block devices (i.e., write-once, CD-
ROM, optical-memory, and direct-access devices) shall be the same. The
segment descriptor format used for stream devices (i.e., printer, processor,
communications, and sequential-access devices), shall be the same. Thus a
copy operation from a write-once device to a printer device uses the same
segment descriptor format as a copy operation from a direct-access device to a
sequential-access device (see Table 7-7). The segment descriptor formats are
described in Tables 7-8 through 7-11. A maximum of 256 segment descriptors
are permitted. The segment descriptors are identified by ascending numbers
beginning with zero.
Table 7-7: COPY Function Codes
==============================================================================
Peripheral Device Type COPY Segment
---------------------- Function Descriptor
Source Destination Code Table Comments
------------------------------------------------------------------------------
Block Devices Stream Devices 0 7-8
(Device types 0,4,5,7) (Device types 1,2,3,9)
Stream Devices Block Devices 1 7-8 (Note 3)
(Device types 1,3,9) (Device types 0,4,5,7)
Block Devices Block Devices 2 7-9 (Note 3)
(Device types 0,4,5,7) (Device types 0,4,5,7)
Stream Devices Stream Devices 3 7-10
(Device types 1,3,9) (Device types 1,2,3,9)
Sequential-Access Sequential-Access 4 7-11 Image Copy
(Device type 1) (Device type 1)
==============================================================================
NOTES:
(1) COPY function codes 05h - 0Fh are reserved.
(2) COPY function codes 10h - 1Fh are vendor specific.
(3) When using the COMPARE command the destination block device may be a CD-
ROM device or an optical-memory device that uses read-only media.
7.2.3.1. Errors Detected by the Managing SCSI Device
Two classes of exception conditions may occur during execution of a COPY
command. The first class consists of those exception conditions detected by
the SCSI device that received the COPY command and is managing the execution
of the command. These conditions include parity errors while transferring the
COPY command and status byte, invalid parameters in the COPY command, invalid
segment descriptors, and inability of the SCSI device controlling the COPY
functions to continue operating. In the event of such an exception condition,
the SCSI device managing the COPY shall:
(1) Terminate the COPY command with CHECK CONDITION status.
(2) The valid bit in the sense data shall be set to one. The segment number
shall contain the number of the segment descriptor being processed at the time
the exception condition is detected. The sense key shall contain the sense
key code describing the exception condition (i.e., not COPY ABORTED). The
information field shall contain the difference between the number of blocks
field in the segment descriptor being processed at the time of the failure and
the number of blocks successfully copied. This number is the residue of
unprocessed blocks remaining for the segment descriptor.
7.2.3.2. Errors Detected by a Target
The second class of errors consists of exception conditions detected by the
SCSI device transferring data at the request of the SCSI device managing the
transfer. The SCSI device managing the COPY command detects exception
conditions by receiving CHECK CONDITION status from one of the SCSI devices it
is managing. It then shall recover the sense data associated with the
exception condition.
The SCSI device managing the COPY command may also be the source or
destination SCSI device (or both). It shall distinguish between a failure of
the management of the COPY and a failure of the data transfer being requested.
It shall then create the appropriate sense data internally.
After recovering the sense data associated with the detected error, the SCSI
device managing the COPY command shall:
(1) Terminate the COPY command with CHECK CONDITION status.
(2) The valid bit in the sense data shall be set to one. The segment number
shall contain the number of the segment descriptor being processed at the time
the exception condition is detected. The sense key shall be set to COPY
ABORTED. The information field shall contain the difference between the
number of blocks field in the segment descriptor being processed at the time
of the failure and the number of blocks successfully copied. This number is
the residue of unprocessed blocks remaining for the segment descriptor.
The first byte of the command-specific information field shall specify the
starting byte number, relative to the first byte of sense data, of an area
that contains (unchanged) the source logical unit's status byte and sense
data. A zero value indicates that no status byte or sense data is being
returned for the source logical unit.
The second byte of the command-specific information field shall specify the
starting byte number, relative to the first byte of sense data, of an area
that contains (unchanged) the destination logical unit's status byte and sense
data. A zero value indicates that no status byte or sense data is being
returned for the destination logical unit.
7.2.3.3. COPY Function Code 00h and 01h
The format for the segment descriptors for COPY transfers between block and
stream devices is specified in Table 7-8. This format is required for COPY
function codes 00h or 01h. The segment descriptor may be repeated up to 256
times within the parameter list length specified in the command descriptor
block.
Table 7-8: Segment Descriptor for COPY Function Codes 00h and 01h
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Source Address |Reserved| Cat | Source LUN |
-----|-----------------------------------------------------------------------|
1 | Destination Address | Reserved | Destination LUN |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- Stream Device Block Length ---|
3 | (LSB) |
-----|-----------------------------------------------------------------------|
4 | (MSB) |
- - -|- - Block Device Number of Blocks - -|
7 | (LSB) |
-----|-----------------------------------------------------------------------|
8 | (MSB) |
- - -|- - Block Device Logical Block Address - -|
11 | (LSB) |
==============================================================================
The source address and source LUN fields specify the SCSI bus ID and logical
unit of the device to copy the data from for this segment of the COPY command.
The destination address and destination LUN fields specify the SCSI bus ID and
logical unit to copy the data to for this segment of the COPY command. Some
SCSI devices may not support third-party COPY in which the copying SCSI device
is not the source or destination device. Some SCSI devices only support COPY
within the SCSI device and not to other SCSI devices. If an unsupported COPY
operation is requested, the command shall be terminated with CHECK CONDITION
status and the sense key shall be set to ILLEGAL REQUEST with an additional
sense code of INVALID FIELD IN PARAMETER LIST (see 7.2.3.1).
A catenate (Cat) bit (optional) of one indicates that the COPY manager shall
catenate the last source block of a segment with the first source block of the
next segment if the last source block does not end exactly at the end of the
destination block. The definition of a cat bit of zero depends on the setting
of the pad bit in the command descriptor block (see 7.2.3.7).
The stream device block-length field specifies the block length to be used
on the stream device logical unit during this segment of the COPY command. If
the SCSI device managing the COPY knows this block length is not supported,
the command shall be terminated with CHECK CONDITION status and the sense key
shall be set to ILLEGAL REQUEST with an additional sense code of INVALID FIELD
IN PARAMETER LIST . If the block length is found to be invalid while executing
a read or write operation to the stream device, the command shall be
terminated with CHECK CONDITION status and the sense key shall be set to COPY
ABORTED (see 7.2.3.2).
The block device number of blocks field specifies the number of blocks in
the current segment to be copied. A value of zero indicates that no blocks
shall be transferred in this segment.
The block device logical block address field specifies the starting logical
block address on the logical unit for this segment.
7.2.3.4. COPY Function Code 02h
The format for the segment descriptors for COPY transfers among block
devices is specified in Table 7-9. This format is required for COPY function
code 02h. The segment descriptor may be repeated up to 256 times within the
parameter list length specified in the command descriptor block.
Table 7-9: Segment Descriptor for COPY Function Code 02h
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Source Address | DC | Cat | Source LUN |
-----|-----------------------------------------------------------------------|
1 | Destination Address | Reserved | Destination LUN |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | (MSB) |
- - -|- - Number of Blocks - -|
7 | (LSB) |
-----|-----------------------------------------------------------------------|
8 | (MSB) |
- - -|- - Source Logical Block Address - -|
11 | (LSB) |
-----|-----------------------------------------------------------------------|
12 | (MSB) |
- - -|- - Destination Logical Block Address - -|
15 | (LSB) |
==============================================================================
See 7.2.3.3 for definitions of the source address, the source LUN, the
destination address, the destination LUN, and CAT fields.
A destination count (DC) bit of zero indicates that the number of blocks
field refers to the source logical unit. A DC bit of one indicates that the
number of blocks field refers to the destination logical unit.
The number of blocks field specifies the number of blocks to be transferred
to or from (depending on the DC bit) the block device during this segment. A
value of zero indicates that no blocks shall be transferred.
The source logical block address field specifies the starting logical block
address on the source block device.
The destination logical block address field specifies the starting logical
block address on the destination block device.
7.2.3.5. COPY Function Code 03h
The format for the segment descriptors for COPY transfers among stream
devices is specified by Table 7-10. This format is required for COPY function
code 03h. The segment descriptor may be repeated up to 256 times within the
parameter list length specified in the command descriptor block.
Table 7-10: Segment Descriptor for COPY Function Code 03h
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Source Address | DC | Cat | Source LUN |
-----|-----------------------------------------------------------------------|
1 | Destination Address | Reserved | Destination LUN |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | (MSB) |
-----|--- Source Block Length ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- Destination Block Length ---|
7 | (LSB) |
-----|-----------------------------------------------------------------------|
8 | (MSB) |
- - -|- - Number of Blocks - -|
11 | (LSB) |
==============================================================================
See 7.2.3.3 for definitions of the source address, the source LUN, the
destination address, the destination LUN, and CAT fields.
A destination count (DC) bit of zero indicates that the number of blocks
field refers to the source logical unit. A DC bit of one indicates that the
number of blocks field refers to the destination logical unit.
The source block length field specifies the block-length of the source
device for this segment of the COPY. A zero in this field indicates variable
block-length. For non-zero values, this field shall match the logical unit's
actual block-length.
If block-length mismatches are detected prior to the beginning of the read
operation by the SCSI device managing the COPY, the command shall be
terminated with CHECK CONDITION status. The sense key shall be set to ILLEGAL
REQUEST and the additional sense code shall be set to INVALID FIELD IN
PARAMETER LIST (see 7.2.3.1).
If the mismatches are detected during the read operation by the COPY
manager, the command shall be terminated with CHECK CONDITION status. The
sense key shall be set to COPY ABORTED (see 7.2.3.2). and the additional
sense code shall be set to INVALID FIELD IN PARAMETER LIST.
The destination block-length field specifies the block length to be used on
the destination logical unit during the COPY. Destination block length
mismatches are handled in an analogous manner as source block length
mismatches.
The number of blocks field specifies the number of blocks to be transferred
to or from (depending on the DC bit) the device during this segment. A value
of zero indicates that no blocks shall be transferred.
7.2.3.6. COPY Function Code 04h
The format for the segment descriptors for image COPY transfers between
sequential-access devices is specified in Table 7-11. This format is required
for COPY function code 04h. The segment descriptor may be repeated up to 256
times within the parameter list length specified in the command descriptor
block.
Table 7-11: Segment Descriptor for COPY Function Code 04h
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Source Address | Reserved | Source LUN |
-----|-----------------------------------------------------------------------|
1 | Destination Address | Reserved | Destination LUN |
-----|-----------------------------------------------------------------------|
2 | Count |
-----|-----------------------------------------------------------------------|
3 | |
- - -|- - Reserved - -|
7 | |
-----|-----------------------------------------------------------------------|
8 | |
- - -|- - Vendor Specific - -|
11 | |
==============================================================================
See 7.2.3.3 for definitions of the source address, the source LUN, the
destination address, the destination LUN, and CAT fields.
The image mode COPY command copies an exact image of the source device
medium to the destination device medium, beginning at their current positions.
The copy function terminates when the source device:
(1) encounters an end-of-partition as defined by the source device
(2) encounters an end-of-data as defined by the source device (i.e., BLANK
CHECK sense key)
(3) has copied the number of consecutive filemarks specified in the count
field from the source device to the destination device
(4) has copied the number of consecutive setmarks specified in the count
field from the source device to the destination device, if the RSmk bit in the
device configuration page (see 9.3.3.1) is one.
A count field of zero indicates that the COPY command shall not terminate
due to any number of consecutive filemarks or setmarks. Other error or
exception conditions (e.g., early-warning end-of-partition on the destination
device) may cause the COPY command to terminate prior to completion. In such
cases, it is not possible to calculate a residue, so the information field in
the sense data shall be set to zero.
7.2.3.7. Copies With Unequal Block Lengths
When copying data between two devices with unequal block lengths, it is
possible for the last source block to not completely fill the last destination
block for one or more segments in the COPY command. Two optional bits are
defined to assist in controlling the copy manager's actions in this
circumstance. The Pad bit (in the command descriptor block) and the Cat bit
(in each applicable segment descriptor) are defined in Table 7-12.
Table 7-12: Pad and Cat Bit Definition
==============================================================================
Pad Cat COPY Manager's Action
---- ---- -------------------------------------------------------------------
0 0 On inexact segments, it is device specific whether the COPY manager
rejects the COPY command with CHECK CONDITION status and ILLEGAL
REQUEST sense key, the COPY manager writes or accepts short blocks
(variable-block mode on sequential-access devices), or the COPY
manager adds pad characters (00h) to the destination block or
strips pad characters from the source block.
1 0 On inexact segments, the COPY manager shall add pad characters
(00h) to the destination block to completely fill the block or it
shall strip pad characters from the source block, always stopping
at the end of a complete block.
X 1 The COPY manager shall always write or read complete blocks. On
inexact segments, the remainder of the block contains data from the
next segment. This code is not valid in the last segment of the
COPY command.
==============================================================================
IMPLEMENTORS NOTE: Use of pad characters is intended to assist in managing
COPY commands between devices of different block lengths where partial-block
residues may occur. The initiator which issued the COPY command is
responsible for management of these pad areas (i.e., remembering where they
are). One possible method is to write the COPY parameter list information
to the destination medium prior to issuing the COPY command for backup and
to read this information prior to issuing the COPY command for restore.
7.2.4. COPY AND VERIFY Command
Table 7-13: COPY AND VERIFY Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (3Ah) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | BytChk | Pad |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | (MSB) |
- - -|- - Parameter List Length - -|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | |
- - -|- - Reserved - -|
8 | |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The COPY AND VERIFY command (Table 7-13) performs the same function as the
COPY command, except that a verification of the data written to the
destination logical unit is performed after the data is written. The
parameter list transferred to the target is the same as for the COPY command.
This parameter list contains the information to identify the logical units
involved in the copy and the length of the copy. See 7.2.3 for additional
information about the COPY command.
A byte check (BytChk) bit of zero causes a medium verification to be
performed with no data comparison. A BytChk bit of one causes a byte-by-byte
compare of data written on the destination medium and the data transferred
from the source medium. If the compare is unsuccessful for any reason, the
copy manager shall return CHECK CONDITION status with the sense key set to
MISCOMPARE. The remaining fields in the sense data shall be set as documented
in the COPY command.
7.2.5. INQUIRY Command
Table 7-14: INQUIRY Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (12h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | EVPD |
-----|-----------------------------------------------------------------------|
2 | Page Code |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Allocation Length |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The INQUIRY command (Table 7-14) requests that information regarding
parameters of the target and its attached peripheral device(s) be sent to the
initiator. An option allows the initiator to request additional information
about the target or logical unit (see 7.2.5.2).
An enable vital product data (EVPD) bit of one specifies that the target
shall return the optional vital product data specified by the page code field.
If the target does not support vital product data and this bit is set to one,
the target shall return CHECK CONDITION status with the sense key set to
ILLEGAL REQUEST and an additional sense code of INVALID FIELD IN CDB.
An EVPD bit of zero specifies that the target shall return the standard
INQUIRY data. If the page code field is not zero, the target shall return
CHECK CONDITION status with the sense key set to ILLEGAL REQUEST and an
additional sense code of INVALID FIELD IN CDB.
The page code field specifies which page of vital product data information
the target shall return (see 7.3.4).
The INQUIRY command shall return CHECK CONDITION status only when the target
cannot return the requested INQUIRY data.
IMPLEMENTORS NOTE: It is recommended that the INQUIRY data be returned even
though the peripheral device may not be ready for other commands.
If an INQUIRY command is received from an initiator with a pending unit
attention condition (i.e., before the target reports CHECK CONDITION status),
the target shall perform the INQUIRY command and shall not clear the unit
attention condition (see 6.9).
IMPLEMENTORS NOTES:
(1) The INQUIRY command is typically used by the initiator after a reset or
power-up condition to determine the device types for system configuration.
To minimize delays after a reset or power-up condition the standard INQUIRY
data should be available without incurring any media access delays. If the
target does store some of the INQUIRY data on the device it may return zeros
or ASCII spaces (20h) in those fields until the data is available from the
device.
(2) The INQUIRY data may change as the target executes its initialization
sequence or in response to a CHANGE DEFINITION command. For example, the
target may contain a minimum command set in its non-volatile memory and may
load its final firmware from the device when it becomes ready. After it has
loaded the firmware it may support more options and therefore return
different supported options information in the INQUIRY data.
7.2.5.1. Standard INQUIRY Data
The standard INQUIRY data (Table 7-15) contains 36 required bytes, followed
by a variable number of vendor-specific parameters. Bytes 56 through 95, if
returned, are reserved for future standardization.
The standard INQUIRY data format is shown in Table 7-15.
Table 7-15: Standard INQUIRY Data Format
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Peripheral Qualifier | Peripheral Device Type |
-----|-----------------------------------------------------------------------|
1 | RMB | Device-Type Modifier |
-----|-----------------------------------------------------------------------|
2 | ISO Version | ECMA Version | ANSI-Approved Version |
-----|-----------------------------------------------------------------------|
3 | AENC | TrmIOP | Reserved | Response Data Format |
-----|-----------------------------------------------------------------------|
4 | Additional Length (n-4) |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | RelAdr | WBus32 | WBus16 | Sync | Linked |Reserved| CmdQue | SftRe |
-----|-+---------------------------------------------------------------------|
8 | (MSB) |
- - -|- - Vendor Identification - -|
15 | (LSB) |
-----|-+---------------------------------------------------------------------|
16 | (MSB) |
- - -|- - Product Identification - -|
31 | (LSB) |
-----|-+---------------------------------------------------------------------|
32 | (MSB) |
- - -|- - Product Revision Level - -|
35 | (LSB) |
-----|-+---------------------------------------------------------------------|
36 | |
- - -|- - Vendor Specific - -|
55 | |
-----|-+---------------------------------------------------------------------|
56 | |
- - -|- - Reserved - -|
95 | |
==============================================================================
| Vendor-Specific Parameters |
==============================================================================
96 to| Vendor-Specific |
n | Parameter Bytes |
==============================================================================
The peripheral qualifier and peripheral device-type fields identify the
device currently connected to the logical unit. If the target is not capable
of supporting a device on this logical unit, this field shall be set to 7Fh
(peripheral qualifier set to 011b and peripheral device type set to 1Fh). The
peripheral qualifier is defined in Table 7-16 and the peripheral device type
is defined in Table 7-17.
Table 7-16: Peripheral Qualifier
==============================================================================
Qualifier Description
--------- ----------------------------------------------------------------
000b The specified peripheral device type is currently connected to
this logical unit. If the target cannot determine whether or
not a physical device is currently connected it shall also use
this peripheral qualifier when returning the INQUIRY data.
Note: This peripheral qualifier does not imply that the device
is ready for access by the initiator.
001b The target is capable of supporting the specified peripheral
device type on this logical unit, however the physical device is
not currently connected to this logical unit.
010b Reserved
011b The target is not capable of supporting a physical device on
this logical unit. For this peripheral qualifier the peripheral
device type shall be set to 1Fh to provide compatibility with
previous versions of SCSI. All other peripheral device type
values are reserved for this peripheral qualifier.
1XXb Vendor specific
==============================================================================
Table 7-17: Peripheral Device Type
==============================================================================
Code Description
----------- ---------------------------------------------------------------
00h Direct-access device (e.g., magnetic disk)
01h Sequential-access device (e.g., magnetic tape)
02h Printer device
03h Processor device
04h Write-once device (e.g., some optical disks)
05h CD-ROM device
06h Scanner device
07h Optical memory device (e.g., some optical disks)
08h Medium Changer device (e.g., jukeboxes)
09h Communications device
0Ah - 0Bh Defined by ASC IT8 (Graphic Arts Pre-Press Devices)
0Ch - 1Eh Reserved
1Fh Unknown or no device type
==============================================================================
A removable medium (RMB) bit of zero indicates that the medium is not
removable. A RMB bit of one indicates that the medium is removable.
The device-type modifier field was defined in SCSI-1 to permit vendor-
specific qualification codes of the device type. This field is retained for
compatibility with SCSI-1. Targets that do not support this field should
return a value of zero.
The usage of non-zero code values in the ISO version and ECMA version fields
are defined by the International Organization for Standardization and the
European Computer Manufacturers Association, respectively. A zero code value
in these fields shall indicate that the target does not claim compliance to
the ISO version of SCSI (ISO IS 9316) or the ECMA version of SCSI (ECMA-111).
It is possible to claim compliance to more than one of these SCSI standards.
The ANSI-approved version field indicates the implemented version of this
standard and is defined in Table 7-18.
Table 7-18: ANSI-Approved Version
==============================================================================
Code Description
------------------------------------------------------------------------------
0h The device might or might not comply to an ANSI-approved standard.
1h The device complies to ANSI X3.131-1986 (SCSI-1).
2h The device complies to this version of SCSI. This code is reserved
to designate this standard upon approval by ANSI.
3h - 7h Reserved
==============================================================================
The asynchronous event notification capability (AENC) bit indicates that the
device supports the asynchronous event notification capability as defined in
6.5.5.
(1) Processor device-type definition: An AENC bit of one indicates that the
processor device is capable of accepting asynchronous event notifications.
An AENC bit of zero indicates that the processor device does not support
asynchronous event notifications.
(2) All other device-types: This bit is reserved.
A terminate I/O process (TrmIOP) bit of one indicates that the device
supports the TERMINATE I/O PROCESS message as defined in 5.6.22. A value of
zero indicates that the device does not support the TERMINATE I/O PROCESS
message.
A response data format value of zero indicates the INQUIRY data format is as
specified in SCSI-1. A response data format value of one indicates
compatibility with some products that were designed prior to the development
of this standard (i.e., CCS). A response data format value of two indicates
that the data shall be in the format specified in this standard. Response
data format values greater than two are reserved.
The additional length field shall specify the length in bytes of the
parameters. If the allocation length of the command descriptor block is too
small to transfer all of the parameters, the additional length shall not be
adjusted to reflect the truncation.
A relative addressing (RelAdr) bit of one indicates that the device supports
the relative addressing mode for this logical unit. If this bit is set to one
the linked command (Linked) bit shall also be set to one since relative
addressing can only be used with linked commands. A RelAdr bit of zero
indicates the device does not support relative addressing for this logical
unit.
A wide bus 32 (WBus32) bit of one indicates that the device supports 32-bit
wide data transfers. A value of zero indicates that the device does not
support 32-bit wide data transfers.
A wide bus 16 (WBus16) bit of one indicates that the device supports 16-bit
wide data transfers. A value of zero indicates that the device does not
support 16-bit wide data transfers.
NOTE: If the values of both the WBus16 and WBus32 bits are zero the device
only supports 8-bit wide data transfers.
A synchronous transfer (Sync) bit of one indicates that the device supports
synchronous data transfer. A value of zero indicates the device does not
support synchronous data transfer.
A linked command (Linked) bit of one indicates that the device supports
linked commands for this logical unit. A value of zero indicates the device
does not support linked commands for this logical unit.
A command queuing (CmdQue) bit of one indicates that the device supports
tagged command queuing for this logical unit. A value of zero indicates the
device does not support tagged command queuing for this logical unit.
A soft reset (SftRe) bit of zero indicates that the device responds to the
RESET condition with the hard RESET alternative (see 5.2.2.1). A SftRe bit of
one indicates that the device responds to the RESET condition with the soft
RESET alternative (see 5.2.2.2).
ASCII data fields shall contain only graphic codes (i.e., code values 20h
through 7Eh). Left-aligned fields shall place any unused bytes at the end of
the field (highest offset) and the unused bytes shall be filled with space
characters (20h). Right-aligned fields shall place any unused bytes at the
start of the field (lowest offset) and the unused bytes shall be filled with
space characters (20h).
The vendor identification field contains eight bytes of ASCII data
identifying the vendor of the product. The data shall be left aligned within
this field.
NOTE: It is intended that this field provide a unique vendor identification
of the manufacturer of the SCSI device. In the absence of a formal
registration procedure, X3T9.2 maintains a list of vendor identification
codes in use. Vendors are requested to voluntarily submit their
identification codes to X3T9.2 to prevent duplication of codes (see Appendix
J).
The product identification field contains sixteen bytes of ASCII data as
defined by the vendor. The data shall be left-aligned within this field.
The product revision level field contains four bytes of ASCII data as
defined by the vendor. The data shall be left-aligned within this field.
7.2.5.2. Vital Product Data
Implementation of vital product data is optional. The information returned
consists of configuration data (e.g., vendor identification, product
identification, model, serial number), manufacturing data (e.g., plant and
date of manufacture), field replaceable unit data and other vendor- or device-
specific data.
The initiator requests the vital product data information by setting the
EVPD bit to one and specifying the page code of the desired vital product data
(see Table 7-72). If the target does not implement the requested page it
shall return CHECK CONDITION status. The a sense key shall be set to ILLEGAL
REQUEST and the additional sense code shall be set to INVALID FIELD IN CDB.
IMPLEMENTORS NOTES:
(1) It is recommended that the target have the ability to execute the
INQUIRY command even when a device error occurs which prohibits normal
command execution. In such a case, CHECK CONDITION status would be returned
for commands other than INQUIRY or REQUEST SENSE. The sense data returned
may contain the field replaceable unit code. The vital product data would
be obtained for the failing device using the INQUIRY command.
(2) This standard defines a format which allows device-independent initiator
software to display the vital product data returned by the INQUIRY command.
For example, the initiator may display the data associated for the field
replaceable unit returned in the sense data. The contents of the data may
be vendor-specific; therefore it may not be usable without detailed
information about the device.
(3) This standard does not define the location or method of storing the
vital product data. The retrieval of the data may require completion of
initialization operations within the device which may induce delays before
the data is available to the initiator. Time-critical requirements are an
implementation consideration and are not addressed in this standard.
7.2.6. LOG SELECT Command
Table 7-19: LOG SELECT Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (4Ch) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | PCR | SP |
-----|-----------------------------------------------------------------------|
2 | PC | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | (MSB) |
-----|--- Parameter List Length ---|
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The LOG SELECT command (Table 7-19) provides a means for the initiator to
manage statistical information maintained by the device about the device or
its logical units. Targets that implement the LOG SELECT command shall also
implement the LOG SENSE command. Structures in the form of log parameters
within log pages are defined as a way to manage the log data. The LOG SELECT
command provides for sending zero or more log pages during a DATA OUT phase.
This standard defines the format of the log pages, but does not define the
exact conditions and events which are logged.
A parameter code reset (PCR) bit of one and a parameter list length of zero
shall cause all implemented parameters to be set to the target-defined default
values (e.g., zero). If the PCR bit is one and a the parameter list length is
greater than zero the command is terminated with CHECK CONDITION status. The
sense key shall be set to ILLEGAL REQUEST and the additional sense code shall
be set to INVALID FIELD IN CDB. A PCR bit of zero specifies that the log
parameters shall not be reset.
A save parameters (SP) bit of one indicates that after performing the
specified LOG SELECT operation the target shall save to non-volatile memory
all parameters identified as savable by the DS bit in the log page (see
7.3.2). A SP bit of zero specifies that parameters shall not be saved.
Saving of log parameters is optional and indicated for each log parameter by
the DS bit in the page. Log parameters may be saved at vendor-specific times
subject to the TSD bit (see 7.3.2) in the log parameter. If the target does
not implement saved parameters for any log parameter and the SP bit is set to
one, the command shall be terminated with CHECK CONDITION status. The sense
key shall be set to ILLEGAL REQUEST, and the additional sense code set to
INVALID FIELD IN CDB.
It is not an error to set the SP bit to one and to set the DS bit of a log
parameter to one. In this case, the parameter value for that log parameter is
not saved.
The page control (PC) field defines the type of parameter values to be
selected. The page control field is defined in Table 7-20.
Table 7-20: Page Control Field
============================================================
Type of Parameter Values
Value LOG SENSE LOG SELECT
----- ------------------------- --------------------------
00b Current Threshold Values Threshold Values
01b Current Cumulative Values Cumulative Values
10b Default Threshold Values Default Threshold Values
11b Default Cumulative Values Default Cumulative Values
============================================================
The current cumulative values may be updated by the target or by the
initiator using the LOG SELECT command to reflect the cumulative number of
events experienced by the target. Fields in the parameter control byte
(7.3.2) of each log parameter control the updating and saving of the current
cumulative parameters.
The target shall set the current threshold parameters to the default
threshold values in response to a LOG SELECT command with the PC field set to
10b and the parameter list length field set to zero.
The target shall set all cumulative parameters to their default values in
response to a LOG SELECT command with the PC field set to 11b and the
parameter list length field set to zero.
The current threshold value can only be modified by the initiator via the
LOG SELECT command. If the initiator attempts to change current threshold
values that are not available or not implemented for that log parameter, then
the target shall terminate the LOG SELECT command with CHECK CONDITION status,
the sense key set to ILLEGAL REQUEST, and the additional sense code set to
INVALID FIELD IN PARAMETER LIST. The saving of current threshold parameters
and the criteria for the current threshold being met are controlled by bits in
the parameter control byte (7.3.2).
IMPLEMENTORS NOTE: Pages or log parameters that are not available may become
available at some later time (e.g., after the device has become ready).
The parameter list length field specifies the length in bytes of the
parameter list that shall be transferred from the initiator to the target
during the DATA OUT phase. A parameter list length of zero indicates that no
pages shall be transferred. This condition shall not be considered an error.
If the initiator sends page codes or parameter codes within the parameter list
that are reserved or not implemented by the target, the target shall terminate
the LOG SELECT command with CHECK CONDITION status. The sense key shall be
set to ILLEGAL REQUEST and the additional sense code set to INVALID FIELD IN
PARAMETER LIST.
If a parameter list length results in the truncation of any log parameter,
the target shall terminate the command with CHECK CONDITION status. The sense
key shall be set to ILLEGAL REQUEST and the additional sense code set to
INVALID FIELD IN CDB.
The initiator should send pages in ascending order by page code value if
multiple pages are sent during a DATA OUT phase. If multiple log parameters
within a page are sent during the DATA OUT phase then they should be sent in
ascending order by parameter code value. The target shall return CHECK
CONDITION status if the initiator sends pages out of order or parameter codes
out of order. The sense key shall be set to ILLEGAL REQUEST and the
additional sense code set to INVALID FIELD IN PARAMETER LIST.
IMPLEMENTORS NOTE: Initiators should issue LOG SENSE commands prior to
issuing LOG SELECT commands to determine supported pages and page lengths.
The target may provide independent sets of log parameters for each logical
unit or for each combination of logical units and initiators. If the target
does not support independent sets of log parameters and any log parameters are
changed that affect other initiators, then the target shall generate an unit
attention condition for all initiators except the one that issued the LOG
SELECT command (see 6.9). This unit attention condition is returned with an
additional sense code of LOG PARAMETERS CHANGED.
If the initiator sends a log parameter that is not supported by the target,
the target shall terminate the command with CHECK CONDITION status, set the
sense key to ILLEGAL REQUEST, and set the additional sense code to INVALID
FIELD IN PARAMETER LIST.
7.2.7. LOG SENSE Command
Table 7-21: LOG SENSE Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (4Dh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | PPC | SP |
-----|-----------------------------------------------------------------------|
2 | PC | Page Code |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | (MSB) |
-----|--- Parameter Pointer ---|
6 | (LSB) |
-----|-----------------------------------------------------------------------|
7 | (MSB) |
-----|--- Allocation Length ---|
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The LOG SENSE command (Table 7-21) provides a means for the initiator to
retrieve statistical information maintained by the device about the device or
its logical units. It is a complementary command to the LOG SELECT command.
The parameter pointer control (PPC) bit controls the type of parameters
requested from the target:
(1) A PPC bit of one indicates that the target shall return a log page with
parameter code values which have changed since the last LOG SELECT or LOG
SENSE command. The target shall return only those parameter codes following
the parameter pointer field.
(2) A PPC bit of zero indicates that the log parameter requested from the
target shall begin with the parameter code specified in the parameter pointer
field and return the number of bytes specified by the allocation length field
in ascending order of parameter codes from the specified log page. A PPC bit
of zero and a parameter pointer field of zero shall cause all available log
parameters for the specified log page to be returned to the initiator subject
to the specified allocation length.
Saving parameters is an optional function of the LOG SENSE command. If the
target does not implement saving log parameters and if the save parameters
(SP) bit is one, then the target shall return CHECK CONDITION status, set the
sense key to ILLEGAL REQUEST, and set the additional sense code to INVALID
FIELD IN CDB.
A SP bit of zero indicates the target shall perform the specified LOG SENSE
command and shall not save any log parameters. If saving log parameters is
implemented, a SP bit of one indicates that the target shall perform the
specified LOG SENSE command and shall save all log parameters identified as
savable by the DS bit (7.3.2) to a non-volatile vendor-specific location.
The page control (PC) field defines the type of parameter values to be
selected (see 7.2.6 for the definition of the page control field). The
parameter values returned by a LOG SENSE command are determined as follows:
(1) The specified parameter values at the last update (in response to a LOG
SELECT or LOG SENSE command or done automatically by the target for cumulative
values).
(2) The saved values if an update has not occurred since the last power-on,
hard RESET condition, or BUS DEVICE RESET message and saved parameters are
implemented.
(3) The default values if an update has not occurred since the last power-
on, hard RESET condition, or BUS DEVICE RESET message and saved values are not
available or not implemented.
The page code field identifies which page of data is being requested (see
Table 7-53). If the page code is reserved or not implemented, the target
shall terminate the command with CHECK CONDITION status. The sense key shall
be set to ILLEGAL REQUEST with the additional sense code set to INVALID FIELD
IN CDB.
The parameter pointer field allows the initiator to request parameter data
beginning from a specific parameter code to the maximum allocation length or
the maximum parameter code supported by the target, whichever is less. If the
value of the parameter pointer field is larger than the largest available
parameter code that can be returned by the target on the specified page, the
target shall terminate the command with CHECK CONDITION status. The sense key
shall be set to ILLEGAL REQUEST and the additional sense code shall be set to
INVALID FIELD IN CDB.
Log parameters within the specified log page shall be transferred in
ascending order according to parameter code.
7.2.8. MODE SELECT(6) Command
Table 7-22: MODE SELECT(6) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (15h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | PF | Reserved | SP |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Parameter List Length |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The MODE SELECT(6) command (Table 7-22) provides a means for the initiator
to specify medium, logical unit, or peripheral device parameters to the
target. Targets that implement the MODE SELECT command shall also implement
the MODE SENSE command. Initiators should issue MODE SENSE prior to MODE
SELECT to determine supported pages, page lengths, and other parameters.
If a target supports saved pages, it may save only one copy of the page for
each logical unit and have it apply to all initiators or it may save separate
copies for each initiator for each logical unit. If separate copies are
saved, the target shall maintain separate current values for each I_T_L nexus.
Pages which are common to all initiators are not required to have multiple
copies.
If an initiator sends a MODE SELECT command that changes any parameters that
apply to other initiators, the target shall generate a unit attention
condition for all initiators except the one that issued the MODE SELECT
command (see 6.9). The target shall set the additional sense code to MODE
PARAMETERS CHANGED.
The target may provide for independent sets of parameters for each attached
logical unit or for each combination of logical unit and initiator. If
independent sets of parameters are implemented, and a third party reservation
is requested the target transfers the set of parameters in effect for the
initiator of the RESERVE command to the parameters used for commands from the
third party device (see 8.2.12.3 and 9.2.10.1).
A page format (PF) bit of zero indicates that the MODE SELECT parameters are
as specified in SCSI-1, (i.e., all parameters after the block descriptors are
vendor-specific. A PF bit of one indicates that the MODE SELECT parameters
following the header and block descriptor(s) are structured as pages of
related parameters and are as specified in this standard.
A save pages (SP) bit of zero indicates the target shall perform the
specified MODE SELECT operation, and shall not save any pages. A SP bit of
one indicates that the target shall perform the specified MODE SELECT
operation, and shall save to a non-volatile vendor-specific location all the
savable pages including any sent during the DATA OUT phase. The SP bit is
optional, even when mode pages are supported by the target. Pages which are
saved are identified by the parameter savable bit that is returned in the page
header by the MODE SENSE command (see 7.2.10.4). If the target does not
implement saved pages and the SP bit is set to one, the command shall be
terminated with CHECK CONDITION status. The sense key shall be set to ILLEGAL
REQUEST, and the additional sense code shall be set to INVALID FIELD IN CDB.
The parameter list length field specifies the length in bytes of the MODE
SELECT parameter list that shall be transferred from the initiator to the
target 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. A parameter list length that results in the truncation of any
descriptor, header or page of parameters shall cause the target to terminate
the command with CHECK CONDITION status. The sense key shall be set to
ILLEGAL REQUEST, and the additional sense code shall be set to PARAMETER LIST
LENGTH ERROR.
The parameter list for the MODE SELECT and MODE SENSE commands is defined in
7.3.3. Parts of each parameter list are uniquely defined for each device-
type.
IMPLEMENTORS NOTE: In some situations where there is a conflict between the
information in the command descriptor block and the information in the
parameter list, one of several additional sense codes may apply. As a
guide, INVALID FIELD IN CDB or PARAMETER LIST LENGTH ERROR should be used if
the error is detected prior to any operations that alter the logical unit's
mode parameters. INVALID FIELD IN PARAMETER LIST should be used if the
logical unit's mode parameters have been altered.
The target shall terminate the MODE SELECT command with CHECK CONDITION
status, set the sense key to ILLEGAL REQUEST and set the additional sense code
to INVALID FIELD IN PARAMETER LIST for the following conditions:
(1) If the initiator attempts to change any field that is not changeable as
reported by the target. In this case, no parameters shall be changed by this
command.
(2) If the initiator attempts to send an unsupported value or a non-zero
value to a reserved field in the MODE SELECT header, block descriptor, or any
page header.
(3) If an initiator attempts to send a page with a length not equal to the
parameter length reported for that page by the MODE SENSE command.
(4) If the initiator attempts to send a value for a parameter that is
outside the range supported by the target and rounding is not implemented for
that parameter.
If the initiator sends a value for a parameter that is outside the range
supported by the target and rounding is implemented for that parameter, the
target may either:
(1) round the parameter to an acceptable value and terminate the command as
described in 6.5.4.
(2) terminate the command with CHECK CONDITION status, the sense key set to
ILLEGAL REQUEST, and the additional sense code set to INVALID FIELD IN
PARAMETER LIST.
7.2.9. MODE SELECT(10) Command
Table 7-23: MODE SELECT(10) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (55h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | PF | Reserved | SP |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | (MSB) |
-----|--- Parameter List Length ---|
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The MODE SELECT(10) command (Table 7-23) provides a means for the initiator
to specify medium, logical unit, or peripheral device parameters to the
target. See the MODE SELECT(6) command (7.2.8) for a description of the
fields in this command. Initiators should issue MODE SENSE prior to MODE
SELECT to determine supported pages, page lengths, and other parameters.
Targets that implement the MODE SELECT(10) command shall also implement the
MODE SENSE(10) command.
7.2.10. MODE SENSE(6) Command
Table 7-24: MODE SENSE(6) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (1Ah) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number |Reserved| DBD | Reserved |
-----|-----------------------------------------------------------------------|
2 | PC | Page Code |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Allocation Length |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The MODE SENSE(6) command (Table 7-24) provides a means for a target to
report parameters to the initiator. It is a complementary command to the MODE
SELECT(6) command.
A disable block descriptors (DBD) bit of zero indicates that the target may
return zero or more block descriptors in the returned MODE SENSE data (see
7.3.3), at the target's discretion. A DBD bit of one specifies that the
target shall not return any block descriptors in the returned MODE SENSE data.
The page control (PC) field defines the type of parameter values to be
returned. The page control field is defined in Table 7-25.
Table 7-25: Page Control Field
================================================
Bit 7 Bit 6 Type of Parameter Values Section
----- ----- ------------------------ --------
0 0 Current Values 7.2.10.1
0 1 Changeable Values 7.2.10.2
1 0 Default Values 7.2.10.3
1 1 Saved Values 7.2.10.4
================================================
The page code specifies which page or pages to return. Page code usage is
defined in Table 7-26.
Table 7-26: Page Code Usage for All Devices
==========================================================
Page Code Description
--------- ----------------------------------------------
00h Vendor Specific (does not require page format)
01h - 1Fh See specific device-types
20h - 3Eh Vendor Specific (page format required)
3Fh Return all pages
==========================================================
An initiator may request any one or all of the supported pages of a target.
If an initiator attempts a MODE SENSE command with a page code value not
implemented by the target, the target shall return CHECK CONDITION status and
shall set the sense key to ILLEGAL REQUEST and the additional sense code to
INVALID FIELD IN CDB.
A page code of 3Fh indicates that all pages implemented by the target shall
be returned to the initiator. Page 00h, if implemented, shall be returned
after all other pages. Targets that implement more than 256 bytes of mode
page parameter data and block descriptors shall return CHECK CONDITION status
to a MODE SENSE(6) request of 3Fh in the page code field. The sense key shall
be set to ILLEGAL REQUEST and the additional sense code shall be set to
INVALID FIELD IN CDB.
IMPLEMENTORS NOTES:
(1) Targets that support more than 256 bytes of block descriptors and
parameter pages should consider implementing the MODE SELECT(10) and MODE
SENSE(10) commands. Targets might not support an entire mode page as
defined in this standard. Typically, the mode pages are returned in
ascending order (except for page 00h).
(2) A target that receives a MODE SENSE command with a PC field and a page
code field of zero should return a mode parameter header and block
descriptor (if applicable). This allows for compatibility with existing
SCSI-1 initiators.
The parameter list for MODE SELECT and MODE SENSE is defined in 7.3.3.
Parts of the parameter lists are specifically defined for each device type.
7.2.10.1. Current Values
A PC field value of 0h requests the target to return the current parameter
values for the specified page code for the logical unit. The current values
returned are:
(1) The parameters set in the last successful MODE SELECT command.
(2) The saved values if a MODE SELECT command has not been executed since
the last power-on, hard RESET condition, or BUS DEVICE RESET message.
(3) The default values if saved values are not available or not supported.
7.2.10.2. Changeable Values
A PC field value of 1h requests the target to return the changeable
parameter mask for the page code specified. The page requested shall be
returned containing information that indicates which parameters are
changeable. All bits of parameters that are changeable shall be set to one.
All bits of parameters that are target defined (not changeable by the
initiator) shall be set to zero.
NOTE: An attempt to change a target-defined parameter (via MODE SELECT)
results in an error condition (see 7.2.8).
IMPLEMENTORS NOTE: The initiator should issue a MODE SENSE command with the
PC field set to 1h and the page code field set to 3Fh to determine which
pages are supported, which parameters within the pages are changeable, and
the supported length of each page prior to issuing any MODE SELECT commands.
7.2.10.3. Default Values
A PC field value of 2h requests the target return the default values for the
page code specified. The page requested shall be returned with each supported
parameter set to its default value. Parameters not supported by the target
shall be set to zero.
7.2.10.4. Saved Values
A PC field value of 3h requests the target return the saved values for the
page code specified. Implementation of saved page parameters is optional.
The page requested shall be returned with the parameters set to their saved
values. Parameters not supported by the target shall be set to zero. If
saved values are not implemented, the command shall be terminated with CHECK
CONDITION status with the sense key set to ILLEGAL REQUEST and the additional
sense code set to SAVING PARAMETERS NOT SUPPORTED.
IMPLEMENTORS NOTE: The method of saving parameters is vendor-specific. The
parameters are preserved in such a manner that they are retained when the
target is powered down. All savable pages can be considered saved when a
MODE SELECT command issued with the SP bit set to one has returned a GOOD
status or after the successful completion of a FORMAT UNIT command.
7.2.10.5. Initial Responses
After a power-up condition or hard reset condition, the target shall respond
in the following manner:
(1) If default values are requested, report the default values.
(2) If saved values are requested, report valid restored parameters, or
restore the parameters and report them. If the saved parameters are not able
to be accessed from the non-volatile vendor-specific location, terminate the
command with CHECK CONDITION status and the sense key set to NOT READY. If
saved parameters are not implemented respond as defined in 7.2.10.4.
(3) If current values are requested and current values have not been sent by
the initiator (via a MODE SELECT command), the target may return either the
default or saved parameters (if implemented), as defined above. If current
values have been sent, the current values shall be reported.
7.2.11. MODE SENSE(10) Command
Table 7-27: MODE SENSE(10) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (5Ah) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number |Reserved| DBD | Reserved |
-----|-----------------------------------------------------------------------|
2 | PC | Page Code |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | (MSB) |
-----|--- Allocation Length ---|
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The MODE SENSE(10) command (Table 7-27) provides a means for a target to
report parameters to the initiator. It is a complementary command to the MODE
SELECT(10) command. If the MODE SELECT(10) command is implemented the MODE
SENSE(10) command shall be implemented. See the MODE SENSE(6) command for a
description of the fields in this command.
7.2.12. READ BUFFER
Table 7-28: READ BUFFER Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (3Ch) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Mode |
-----|-----------------------------------------------------------------------|
2 | Buffer ID |
-----|-----------------------------------------------------------------------|
3 | (MSB) |
- - -|- - Buffer Offset - -|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
- - -|- - Allocation Length - -|
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The READ BUFFER command (Table 7-28) is used in conjunction with the WRITE
BUFFER command as a diagnostic function for testing target memory and the SCSI
bus integrity. This command shall not alter the medium.
The function of this command and the meaning of fields within the command
descriptor block depend on the contents of the mode field. The mode field is
defined in Table 7-29.
Table 7-29: READ BUFFER Mode Field
===============================================
Mode Description Type
---- ------------------------ ---------------
000b Combined header and data Optional
001b Vendor-specific Vendor specific
010b Data Optional
011b Descriptor Optional
100b Reserved Reserved
101b Reserved Reserved
110b Reserved Reserved
111b Reserved Reserved
===============================================
IMPLEMENTORS NOTE: Modes 000b and 001b are included for compatibility with
products that were designed prior to the generation of this standard. Some
products that were designed prior to the generation of this standard
restrict the available length to to 65535 bytes.
7.2.12.1. Combined Header and Data Mode (000b)
In this mode, a four-byte header followed by data bytes are returned to the
initiator during the DATA IN phase. The buffer ID and the buffer offset
fields are reserved.
The four-byte READ BUFFER header (Table 7-30) is followed by data bytes from
the target's data buffer.
Table 7-30: READ BUFFER Header
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Reserved |
-----|-----------------------------------------------------------------------|
1 | (MSB) |
- - -|- - Buffer Capacity - -|
3 | (LSB) |
==============================================================================
The buffer capacity field specifies the total number of data bytes that are
available in the target's data buffer. This number is not reduced to reflect
the allocation length nor is it reduced to reflect the actual number of bytes
written using the WRITE BUFFER command. Following the READ BUFFER header, the
target shall transfer data from its data buffer. The target terminates the
DATA IN phase when allocation length bytes of header plus data have been
transferred or when all available header and buffer data have been transferred
to the initiator, whichever is less.
7.2.12.2. Vendor-Specific Mode (001b)
In this mode, the meaning of the buffer ID, buffer offset, and allocation
length fields are not specified by this standard.
7.2.12.3. Data Mode (010b)
In this mode, the DATA IN phase contains buffer data. The buffer ID field
identifies a specific buffer within the target from which data shall be
transferred. The vendor assigns buffer ID codes to buffers within the target.
Buffer ID zero shall be supported. If more than one buffer is supported,
additional buffer ID codes shall be assigned contiguously, beginning with one.
Buffer ID code assignments for the READ BUFFER command shall be the same as
for the WRITE BUFFER command. If an unsupported buffer ID code is selected,
the target shall return CHECK CONDITION status, shall set the sense key to
ILLEGAL REQUEST and set the additional sense code to ILLEGAL FIELD IN CDB.
The target terminates the DATA IN phase when allocation length bytes have been
transferred or when all the available data from the buffer has been
transferred to the initiator, whichever is less.
The buffer offset field contains the byte offset within the specified buffer
where data shall be transferred from. The initiator should conform to the
offset boundary requirements returned in the READ BUFFER descriptor (see
7.2.12.4). If the target is unable to accept the specified buffer offset, it
shall return CHECK CONDITION status, shall set the sense key to ILLEGAL
REQUEST and set the additional sense code to ILLEGAL FIELD IN CDB.
7.2.12.4. Descriptor Mode (011b)
In this mode, a maximum of four bytes of READ BUFFER descriptor information
are returned. The target shall return the descriptor information for the
buffer specified by the buffer ID (see the description of the buffer ID in
7.2.12.3). If there is no buffer associated with the specified buffer ID, the
target shall return all zeros in the READ BUFFER descriptor. The buffer
offset field is reserved in this mode. The allocation length should be set to
four or greater. The target shall transfer the lesser of the allocation
length or four bytes of READ BUFFER descriptor. The READ BUFFER descriptor is
defined as shown in Table 7-31.
Table 7-31: READ BUFFER Descriptor
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Offset Boundary |
-----|-----------------------------------------------------------------------|
1 | (MSB) |
- - -|- - Buffer Capacity - -|
3 | (LSB) |
==============================================================================
The offset boundary field returns the boundary alignment within the selected
buffer for subsequent WRITE BUFFER and READ BUFFER commands. The value
contained in the offset boundary field shall be interpreted as a power of two.
The value contained in the buffer offset field of subsequent WRITE BUFFER
and READ BUFFER commands should be a multiple of 2offset boundary as shown in
Table 7-32.
Table 7-32: Buffer Offset Boundary
==============================================================================
Offset
Boundary 2Offset Boundary Buffer Offsets
-------- ---------------- --------------------------------------
0 20 = 1 Byte boundaries
1 21 = 2 Even-byte boundaries
2 22 = 4 Four-byte boundaries
3 23 = 8 Eight-byte boundaries
4 24 = 16 16-byte boundaries
. . .
. . .
. . .
FFh Not Applicable 0 is the only supported buffer offset.
==============================================================================
The buffer capacity field shall return the size of the selected buffer in
bytes.
IMPLEMENTORS NOTE: In a multi-tasking system, a buffer may be altered
between the WRITE BUFFER and READ BUFFER commands by another task. Buffer
testing applications may wish to insure that only a single task is active.
Use of reservations (to all logical units on the device) or linked commands
may also be helpful in avoiding buffer alteration between these two
commands.
7.2.13. RECEIVE DIAGNOSTIC RESULTS Command
Table 7-33: RECEIVE DIAGNOSTIC RESULTS Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (1Ch) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | (MSB) |
-----|--- Allocation Length ---|
4 | (LSB) |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The RECEIVE DIAGNOSTIC RESULTS command (Table 7-33) requests analysis data
be sent to the initiator after completion of a SEND DIAGNOSTIC command (see
7.2.15). If the target supports the optional page format the page code field
sent in the previous SEND DIAGNOSTIC command specifies the format of the
returned data.
IMPLEMENTORS NOTES:
(1) To insure that the diagnostic command information is not destroyed by a
command sent from another initiator, the SEND DIAGNOSTIC command should
either be linked to the RECEIVE DIAGNOSTIC RESULTS command or the logical
unit should be reserved.
(2) Although diagnostic software is generally device-specific, this command
and the SEND DIAGNOSTIC command provide a means to isolate the operating
system software from the device-specific diagnostic software. Hence the
operating system can remain device-independent. This also allows diagnostic
software to be more easily transferred to other operating systems.
See 7.3.1 for RECEIVE DIAGNOSTIC RESULTS page format definitions.
7.2.14. REQUEST SENSE Command
Table 7-34: REQUEST SENSE Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (03h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Allocation Length |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The REQUEST SENSE command (Table 7-34) requests that the target transfer
sense data to the initiator.
The sense data:
(1) shall be available if the previous command to the specified I_T_x nexus
terminated with CHECK CONDITION or COMMAND TERMINATED status
(2) shall be available if other information (e.g., medium position) is
available in any field
(3) may be available if the previous command to the specified I_T_x nexus
ended with an unexpected BUS FREE error (5.1.1).
If the target has no sense data available to return, it shall return a sense
key of NO SENSE and an additional sense code of NO ADDITIONAL SENSE
INFORMATION.
The sense data shall be preserved by the target for the initiator until
retrieved by the REQUEST SENSE command or until the receipt of any other
command for the same I_T_x nexus (see 6.6). Sense data shall be cleared upon
receipt of any subsequent command (including REQUEST SENSE) to the same I_T_x
nexus.
IMPLEMENTORS NOTE: Some target implementations do not update sense data
except on commands that return CHECK CONDITION or COMMAND TERMINATED status.
Thus when polling for a logical unit to become ready, the initiator should
issue TEST UNIT READY commands until GOOD status is returned. If desired,
the initiator may issue REQUEST SENSE commands after the TEST UNIT READY
commands that return CHECK CONDITION or COMMAND TERMINATED status to obtain
the sense data.
The target shall return CHECK CONDITION status for a REQUEST SENSE command
only to report errors specific to the command itself. For example:
(1) A non-zero reserved bit is detected in the command descriptor block.
(2) An unrecovered parity error is detected on the data bus.
(3) A target malfunction prevents return of the sense data.
If a recovered error occurs during the execution of the REQUEST SENSE
command, the target shall return the sense data with GOOD status. If a target
returns CHECK CONDITION status for a REQUEST SENSE command the sense data may
be invalid.
IMPLEMENTORS NOTE: The sense data appropriate to the selection of an
invalid logical unit is defined in 6.5.3.
Targets shall be capable of returning eighteen bytes of data in response to
a REQUEST SENSE command. If the allocation length is eighteen or greater and
a target returns less than eighteen bytes of data the initiator should assume
that the bytes not transferred would have been zeros had the target returned
those bytes. Initiators can determine how much sense data has been returned
by examining the allocation length parameter in the command descriptor block
and the additional sense length in the sense data. Targets shall not adjust
the additional sense length to reflect truncation if the allocation length is
less than the sense data available.
Table 7-35: Error Codes 70h and 71h Sense Data Format
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Valid | Error Code (70h or 71h) |
-----|-----------------------------------------------------------------------|
1 | Segment Number |
-----|-----------------------------------------------------------------------|
2 |Filemark| EOM | ILI |Reserved| Sense Key |
-----|-----------------------------------------------------------------------|
3 | (MSB) |
- - -|- - Information - -|
6 | (LSB) |
-----|-----------------------------------------------------------------------|
7 | Additional Sense Length (n-7) |
-----|-----------------------------------------------------------------------|
8 | (MSB) |
- - -|- - Command-Specific Information - -|
11 | (LSB) |
-----|-----------------------------------------------------------------------|
12 | Additional Sense Code |
-----|-----------------------------------------------------------------------|
13 | Additional Sense Code Qualifier |
-----|-----------------------------------------------------------------------|
14 | Field Replaceable Unit Code |
-----|-----------------------------------------------------------------------|
15 to| SKSV | |
- - -|---------- - Sense-Key Specific - -|
17 | |
-----|-----------------------------------------------------------------------|
18 to| |
- - -|- - Additional Sense Bytes - -|
n | |
==============================================================================
A valid bit of zero indicates that the information field is not as defined
in this standard. A valid bit of one indicates the information field contains
valid information as defined in this standard. Targets shall implement the
valid bit.
The sense data format for error codes 70h (current errors) and 71h (deferred
errors) are defined in Table 7-35. Error code values of 72h to 7Eh are
reserved. Error code 7Fh is for a vendor-specific sense data format. Targets
shall implement error code 70h; implementation of error code 71h is optional.
Error code values of 00h to 6Fh are not defined by this standard and their use
is not recommended.
The segment number field contains the number of the current segment
descriptor if the REQUEST SENSE command is in response to a COPY, COMPARE, or
COPY AND VERIFY command. Up to 256 segments are supported beginning with
segment zero.
The filemark bit is mandatory for sequential-access devices and this bit is
reserved for all other device types. A filemark bit of one indicates that the
current command has read a filemark or setmark. The additional sense code
field may be used to indicate whether a filemark or setmark was read.
Reporting of setmarks is optional and indicated by the RSmk bit for
sequential-access devices in the configuration parameters page (see 9.3.3).
The end-of-medium (EOM) bit is mandatory for sequential-access and printer
devices and this bit is reserved for all other device types. An EOM bit of
one indicates that an end-of-medium condition (end-of-partition, beginning-of-
partition, out-of-paper, etc.) exists. For sequential-access devices, this
bit indicates that the unit is at or past the early-warning if the direction
was forward or that the command could not be completed because beginning-of-
partition was encountered if the direction was reverse.
An incorrect length indicator (ILI) bit of one usually indicates that the
requested logical block length did not match the logical block length of the
data on the medium.
The sense key, additional sense code and additional sense code qualifier
provide a hierarchy of information. The intention of the hierarchy is to
provide a top-down approach for an initiator to determine information relating
to the error and exception conditions. The sense key provides generic
categories in which error and exception conditions can be reported.
Initiators would typically use sense keys for high level error recovery
procedures. Additional sense codes provide further detail describing the
sense key. Additional sense code qualifiers add further detail to the
additional sense code. The additional sense code and additional sense code
qualifier can be used by initiators where sophisticated error recovery
procedures require detailed information describing the error and exception
conditions.
The sense key field is mandatory and indicates generic information
describing an error or exception condition. The sense keys are defined in
Tables 7-39 and 7-40.
The contents of the information field is device-type or command specific and
is defined within the appropriate section for the device type or command of
interest. Targets shall implement the information field. Unless specified
otherwise, this field contains:
(1) The unsigned logical block address associated with the sense key, for
direct-access devices (Device Type 0), write-once devices (Device Type 4), CD-
ROM devices (Device Type 5), and optical memory devices (Device Type 7).
(2) The difference (residue) of the requested length minus the actual length
in either bytes or blocks, as determined by the command, for sequential-access
devices (Device Type 1), printer devices (Device Type 2), processor devices
(Device Type 3) and some direct access device commands, except as defined for
(4) below. (Negative values are indicated by two's complement notation.)
(3) The difference (residue) of the requested number of blocks minus the
actual number of blocks copied or compared for the current segment descriptor
of a COPY, COMPARE, or COPY AND VERIFY command.
(4) For sequential-access devices operating in buffered modes 1h or 2h that
detect an unrecoverable write error when unwritten data blocks, filemarks, or
setmarks remain in the buffer, the value of the information field for all
commands shall be:
(a) the total number of data blocks, filemarks, and setmarks in the
buffer if the device is in fixed block mode (block length field of the MODE
SENSE block descriptor is non-zero and the fixed bit of the WRITE command is
one).
(b) the number of bytes in the buffer, including filemarks and setmarks,
if the device is in variable mode (the fixed bit of the WRITE command is
zero).
The additional sense length field indicates the number of additional sense
bytes to follow. If the allocation length of the command descriptor block is
too small to transfer all of the additional sense bytes, the additional sense
length is not adjusted to reflect the truncation.
The command-specific information field contains information that depends on
the command which was executed. Further meaning for this field is defined
within the command description. The command-specific information field is
mandatory if the target supports any of the following commands: COPY,
COMPARE, COPY AND VERIFY, SEARCH DATA, and REASSIGN BLOCKS.
The additional sense code field indicates further information related to the
error or exception condition reported in the sense key field. Targets shall
support the additional sense code field. Support of the additional sense
codes not explicitly required by this standard is optional. A list of
additional sense codes is in Table 7-41. If the target does not have further
information related to the error or exception condition, the additional sense
code is set to NO ADDITIONAL SENSE INFORMATION.
The additional sense code qualifier indicates detailed information related
to the additional sense code. The additional sense code qualifier is
optional. If the error or exception condition is reportable by the device the
value returned shall be as specified in Table 7-41. If the target does not
have detailed information related to the error or exception condition, the
additional sense code qualifier is set to zero.
Non-zero values in the field replaceable unit code field are used to define
a device-specific mechanism or unit that has failed. A value of zero in this
field shall indicate that no specific mechanism or unit has been identified to
have failed or that the data is not available. The field replaceable unit
code field is optional. The format of this information is not specified by
this standard. Additional information about the field replaceable unit may be
available in the ASCII information page (see 7.3.4.2), if supported by the
target.
The sense-key specific bytes are described in 7.2.14.1, below.
The additional sense bytes field may contain command specific data,
peripheral device specific data, or vendor-specific data that further defines
the nature of the CHECK CONDITION status.
7.2.14.1. Sense-Key Specific
The sense-key specific field is defined by this standard when the value of
the sense-key specific valid (SKSV) bit is one. The sense-key specific valid
bit and sense-key specific field are optional. The definition of this field
is determined by the value of the sense key field. This field is reserved for
sense keys not described below. An SKSV value of zero indicates that this
field is not defined by this standard.
If the sense key field is set to ILLEGAL REQUEST and the SKSV bit is set to
one, the sense-key specific field shall be defined as shown in Table 7-36.
These Field Pointer field indicates which illegal parameters in command
descriptor blocks or data parameters are in error.
Table 7-36: Field Pointer Bytes
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
15 | SKSV | C/D |Reserved|Reserved| BPV | Bit Pointer |
-----|-----------------------------------------------------------------------|
16 | (MSB) |
-----|--- Field Pointer ---|
17 | (LSB) |
==============================================================================
A command data (C/D) bit of one indicates that the illegal parameter is in
the command descriptor block. A C/D bit of zero indicates that the illegal
parameter is in the data parameters sent by the initiator during the DATA OUT
phase.
A bit pointer valid (BPV) bit of zero indicates that the value in the bit
pointer field is not valid. A BPV bit of one indicates that the bit pointer
field specifies which bit of the byte designated by the field pointer field is
in error. When a multiple-bit field is in error, the bit pointer field shall
point to the most-significant (left-most) bit of the field.
The field pointer field indicates which byte of the command descriptor block
or of the parameter data was in error. Bytes are numbered starting from zero,
as shown in the tables describing the commands and parameters. When a
multiple-byte field is in error, the pointer shall point to the most-
significant (left-most) byte of the field.
IMPLEMENTORS NOTE: Bytes identified as being in error are not necessarily
the place that has to be changed to correct the problem.
If the sense key is RECOVERED ERROR, HARDWARE ERROR or MEDIUM ERROR and if
the SKSV bit is one, the sense-key specific field shall be defined as shown in
Table 7-37.
Table 7-37: Actual Retry Count Bytes
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
15 | SKSV | Reserved |
-----|-----------------------------------------------------------------------|
16 | (MSB) |
-----|--- Actual Retry Count ---|
17 | (LSB) |
==============================================================================
The actual retry count field returns implementation-specific information on
the actual number of retries of the recovery algorithm used in attempting to
recover an error or exception condition.
IMPLEMENTORS NOTE: It is recommended that this field relate to the retry
count fields within the error recovery page of the MODE SELECT command.
If the sense key is NOT READY and the SKSV bit is one, the sense-key
specific field shall be defined as shown in Table 7-38. These fields are only
defined for the FORMAT UNIT command with the Immed bit set to one.
Table 7-38: Format Progress Indication Bytes
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
15 | SKSV | Reserved |
-----|-----------------------------------------------------------------------|
16 | (MSB) |
-----|--- Progress Indication ---|
17 | (LSB) |
==============================================================================
The progress indication field is a percent complete indication in which the
returned value is the numerator that has 65536 (10000h) as its denominator.
The progress indication shall be an based upon the total format operation
including any certification or initialization operations.
IMPLEMENTORS NOTE: It is intended that the progress indication be time
related. However, since format time varies with the number of defects
encountered, etc., it is reasonable for the target to assign values to
various steps within the process. The granularity of these steps should be
small enough to provide reasonable assurances to the initiator that progress
is being made.
7.2.14.2. Deferred Errors
Error code 70h indicates that the CHECK CONDITION or COMMAND TERMINATED
status returned is the result of an error or exception condition on the
command that returned the CHECK CONDITION or COMMAND TERMINATED status or an
unexpected bus free condition. This includes errors generated during
execution of the command by the actual execution process. It also includes
errors not related to any command that are first observed during execution of
a command. Examples of this latter type of error include disk servo-mechanism
off-track errors and power-up test errors.
Error Code 71h (deferred error) indicates that the CHECK CONDITION status
returned is the result of an error or exception condition that occurred during
execution of a previous command for which GOOD status has already been
returned. Such commands are associated with use of the immediate bit, with
some forms of caching, and with multiple command buffering. Targets that
implement these features are required to implement deferred error reporting.
The deferred error indication may be sent at a time selected by the target
through the asynchronous event notification process (see 6.5.5) if AEN is
supported by both the initiator and target.
If AEN is not supported, the deferred error may be indicated by returning
CHECK CONDITION status to the the appropriate initiator as described below.
The subsequent execution of a REQUEST SENSE command shall return the deferred
error sense information.
If CHECK CONDITION status for a deferred error is returned, the current
command has not performed any storage operations or output operations to the
media. After the target detects a deferred error condition on a logical unit,
it shall return a deferred error according to the rules described below:
(1) If a deferred error can be recovered with no external system
intervention, a deferred error indication shall not be posted unless required
by the error handling parameters of the MODE SELECT command. The occurrence
of the error may be logged if statistical or error logging is supported.
(2) If a deferred error can be associated with a causing initiator and with
a particular function or a particular subset of data, and the error is either
unrecovered or required to be reported by the mode parameters, a deferred
error indication shall be returned to the causing initiator. If an initiator
other than the causing initiator attempts access to the particular function or
subset of data associated with the deferred error, a BUSY status shall be
returned to that initiator in response to the command attempting the access.
NOTE: Not all devices may be sufficiently sophisticated to identify the
function or data that has failed. Those that cannot should treat the error
in the following manner.
(3) If a deferred error cannot be associated with a causing initiator or
with a particular subset of data, a deferred error indication shall be
returned on behalf of the failing logical unit to each initiator. If multiple
deferred errors have accumulated for some initiators, only the last error
shall be returned.
(4) If a deferred error cannot be associated with a particular logical unit,
it shall be returned to the appropriate initiator for all logical units
supported by the target.
(5) If a current command has not yet started executing, and a deferred error
occurs, the command shall be terminated with CHECK CONDITION status and
deferred error information posted in the sense data. By convention, the
current command is considered to have started execution if the target has
changed phase from the COMMAND phase to the next normal phase of the command
sequence. If a deferred error occurs while a current command is executing and
the current command has been affected by the error, the command shall be
terminated by CHECK CONDITION status and current error information shall be
returned in the sense data. In this case, if the current error information
does not adequately define the deferred error condition, a deferred error may
be returned after the current error information has been recovered. If a
deferred error occurs while a current command is executing and the current
command completes successfully, the target may choose to return the deferred
error information after the completion of the current command.
IMPLEMENTORS NOTE: Deferred errors may indicate that an operation was
unsuccessful long after the command performing the data transfer returned
GOOD status. If data that cannot be replicated or recovered from other
sources is being stored using such buffered write operations,
synchronization commands should be performed before the critical data is
destroyed in the host initiator. This is necessary to be sure that recovery
actions can be taken if deferred errors do occur in the storing of the data.
If AEN is not implemented, the synchronizing process should provide the
necessary commands to allow returning CHECK CONDITION status and subsequent
returning of deferred error sense information after all buffered operations
are guaranteed to be complete.
Table 7-39: Sense Key (0h-7h) Descriptions
==============================================================================
Sense Key Description
--------- -------------------------------------------------------------------
0h NO SENSE. Indicates that there is no specific sense key
information to be reported for the designated logical unit. This
would be the case for a successful command or a command that
received CHECK CONDITION or COMMAND TERMINATED status because one
of the filemark, EOM, or ILI bits is set to one.
1h RECOVERED ERROR. Indicates that the last command completed
successfully with some recovery action performed by the target.
Details may be determinable by examining the additional sense bytes
and the information field. When multiple recovered errors occur
during one command, the choice of which error to report (first,
last, most severe, etc.) is device specific.
2h NOT READY. Indicates that the logical unit addressed cannot be
accessed. Operator intervention may be required to correct this
condition.
3h MEDIUM ERROR. Indicates that the command terminated with a non-
recovered error condition that was probably caused by a flaw in the
medium or an error in the recorded data. This sense key may also
be returned if the target is unable to distinguish between a flaw
in the medium and a specific hardware failure (sense key 4h).
4h HARDWARE ERROR. Indicates that the target detected a non-
recoverable hardware failure (for example, controller failure,
device failure, parity error, etc.) while performing the command or
during a self test.
5h ILLEGAL REQUEST. Indicates that there was an illegal parameter in
the command descriptor block or in the additional parameters
supplied as data for some commands (FORMAT UNIT, SEARCH DATA,
etc.). If the target detects an invalid parameter in the command
descriptor block, then it shall terminate the command without
altering the medium. If the target detects an invalid parameter in
the additional parameters supplied as data, then the target may
have already altered the medium. This sense key may also indicate
that an invalid IDENTIFY message was received (5.6.7).
6h UNIT ATTENTION. Indicates that the removable medium may have been
changed or the target has been reset. See 6.9 for more detailed
information about the unit attention condition.
7h DATA PROTECT. Indicates that a command that reads or writes the
medium was attempted on a block that is protected from this
operation. The read or write operation is not performed.
==============================================================================
Table 7-40: Sense Key (8h-Fh) Descriptions
==============================================================================
Sense Key Description
--------- -------------------------------------------------------------------
8h BLANK CHECK. Indicates that a write-once device or a sequential-
access device encountered blank medium or format-defined end-of-
data indication while reading or a write-once device encountered a
non-blank medium while writing.
9h Vendor Specific. This sense key is available for reporting vendor
specific conditions.
Ah COPY ABORTED. Indicates a COPY, COMPARE, or COPY AND VERIFY
command was aborted due to an error condition on the source device,
the destination device, or both. (See 7.2.3.2 for additional
information about this sense key.)
Bh ABORTED COMMAND. Indicates that the target aborted the command.
The initiator may be able to recover by trying the command again.
Ch EQUAL. Indicates a SEARCH DATA command has satisfied an equal
comparison.
Dh VOLUME OVERFLOW. Indicates that a buffered peripheral device has
reached the end-of-partition and data may remain in the buffer that
has not been written to the medium. A RECOVER BUFFERED DATA
command(s) may be issued to read the unwritten data from the
buffer.
Eh MISCOMPARE. Indicates that the source data did not match the data
read from the medium.
Fh RESERVED.
==============================================================================
Table 7-41: ASC and ASCQ Assignments
==============================================================================
ASC AND ASCQ ASSIGNMENTS
D = DIRECT ACCESS DEVICE
T = SEQUENTIAL ACCESS DEVICE
L = PRINTER DEVICE
P = PROCESSOR DEVICE
W = WRITE ONCE READ MULTIPLE DEVICE
R = READ ONLY (CD-ROM) DEVICE
S = SCANNER DEVICE
O = OPTICAL MEMORY DEVICE
M = MEDIA CHANGER DEVICE
C = COMMUNICATION DEVICE
BYTE
12 13 DTLPWRSOMC DESCRIPTION
-- -- ------------------------------------------------------------
13 00 D W O ADDRESS MARK NOT FOUND FOR DATA FIELD
12 00 D W O ADDRESS MARK NOT FOUND FOR ID FIELD
00 11 R AUDIO PLAY OPERATION IN PROGRESS
00 12 R AUDIO PLAY OPERATION PAUSED
00 14 R AUDIO PLAY OPERATION STOPPED DUE TO ERROR
00 13 R AUDIO PLAY OPERATION SUCCESSFULLY COMPLETED
00 04 T S BEGINNING-OF-PARTITION/MEDIUM DETECTED
14 04 T BLOCK SEQUENCE ERROR
30 02 DT WR O CANNOT READ MEDIUM - INCOMPATIBLE FORMAT
30 01 DT WR O CANNOT READ MEDIUM - UNKNOWN FORMAT
52 00 T CARTRIDGE FAULT
3F 02 DTLPWRSOMC CHANGED OPERATING DEFINITION
11 06 WR O CIRC UNRECOVERED ERROR
30 03 DT CLEANING CARTRIDGE INSTALLED
4A 00 DTLPWRSOMC COMMAND PHASE ERROR
2C 00 DTLPWRSOMC COMMAND SEQUENCE ERROR
2F 00 DTLPWRSOMC COMMANDS CLEARED BY ANOTHER INITIATOR
2B 00 DTLPWRSO C COPY CANNOT EXECUTE SINCE HOST CANNOT DISCONNECT
41 00 D DATA PATH FAILURE (SHOULD USE 40 NN)
4B 00 DTLPWRSOMC DATA PHASE ERROR
11 07 W O DATA RESYCHRONIZATION ERROR
16 00 D W O DATA SYNCHRONIZATION MARK ERROR
19 00 D O DEFECT LIST ERROR
19 03 D O DEFECT LIST ERROR IN GROWN LIST
19 02 D O DEFECT LIST ERROR IN PRIMARY LIST
19 01 D O DEFECT LIST NOT AVAILABLE
1C 00 D O DEFECT LIST NOT FOUND
32 01 D W O DEFECT LIST UPDATE FAILURE
40 NN DTLPWRSOMC DIAGNOSTIC FAILURE ON COMPONENT NN (80H-FFH)
63 00 R END OF USER AREA ENCOUNTERED ON THIS TRACK
00 05 T S END-OF-DATA DETECTED
14 03 T END-OF-DATA NOT FOUND
00 02 T S END-OF-PARTITION/MEDIUM DETECTED
51 00 T O ERASE FAILURE
0A 00 DTLPWRSOMC ERROR LOG OVERFLOW
11 02 DT W SO ERROR TOO LONG TO CORRECT
==============================================================================
Table 7-41: ASC and ASCQ Assignments (continued)
==============================================================================
BYTE
12 13 DTLPWRSOMC DESCRIPTION
-- -- ------------------------------------------------------------
03 02 T EXCESSIVE WRITE ERRORS
3B 07 L FAILED TO SENSE BOTTOM-OF-FORM
3B 06 L FAILED TO SENSE TOP-OF-FORM
00 01 T FILEMARK DETECTED
14 02 T FILEMARK OR SETMARK NOT FOUND
09 02 WR O FOCUS SERVO FAILURE
31 01 D L O FORMAT COMMAND FAILED
58 00 O GENERATION DOES NOT EXIST
1C 02 D O GROWN DEFECT LIST NOT FOUND
00 06 DTLPWRSOMC I/O PROCESS TERMINATED
10 00 D W O ID CRC OR ECC ERROR
22 00 D ILLEGAL FUNCTION (SHOULD USE 20 00, 24 00, OR 26 00)
64 00 R ILLEGAL MODE FOR THIS TRACK
28 01 M IMPORT OR EXPORT ELEMENT ACCESSED
30 00 DT WR OM INCOMPATIBLE MEDIUM INSTALLED
11 08 T INCOMPLETE BLOCK READ
48 00 DTLPWRSOMC INITIATOR DETECTED ERROR MESSAGE RECEIVED
3F 03 DTLPWRSOMC INQUIRY DATA HAS CHANGED
44 00 DTLPWRSOMC INTERNAL TARGET FAILURE
3D 00 DTLPWRSOMC INVALID BITS IN IDENTIFY MESSAGE
2C 02 S INVALID COMBINATION OF WINDOWS SPECIFIED
20 00 DTLPWRSOMC INVALID COMMAND OPERATION CODE
21 01 M INVALID ELEMENT ADDRESS
24 00 DTLPWRSOMC INVALID FIELD IN CDB
26 00 DTLPWRSOMC INVALID FIELD IN PARAMETER LIST
49 00 DTLPWRSOMC INVALID MESSAGE ERROR
11 05 WR O L-EC UNCORRECTABLE ERROR
60 00 S LAMP FAILURE
5B 02 DTLPWRSOM LOG COUNTER AT MAXIMUM
5B 00 DTLPWRSOM LOG EXCEPTION
5B 03 DTLPWRSOM LOG LIST CODES EXHAUSTED
2A 02 DTL WRSOMC LOG PARAMETERS CHANGED
21 00 DT WR OM LOGICAL BLOCK ADDRESS OUT OF RANGE
08 00 DTL WRSOMC LOGICAL UNIT COMMUNICATION FAILURE
08 02 DTL WRSOMC LOGICAL UNIT COMMUNICATION PARITY ERROR
08 01 DTL WRSOMC LOGICAL UNIT COMMUNICATION TIME-OUT
05 00 DTL WRSOMC LOGICAL UNIT DOES NOT RESPOND TO SELECTION
4C 00 DTLPWRSOMC LOGICAL UNIT FAILED SELF-CONFIGURATION
3E 00 DTLPWRSOMC LOGICAL UNIT HAS NOT SELF-CONFIGURED YET
04 01 DTLPWRSOMC LOGICAL UNIT IS IN PROCESS OF BECOMING READY
04 00 DTLPWRSOMC LOGICAL UNIT NOT READY, CAUSE NOT REPORTABLE
04 04 DTL O LOGICAL UNIT NOT READY, FORMAT IN PROGRESS
04 02 DTLPWRSOMC LOGICAL UNIT NOT READY, INITIALIZING COMMAND REQUIRED
04 03 DTLPWRSOMC LOGICAL UNIT NOT READY, MANUAL INTERVENTION REQUIRED
25 00 DTLPWRSOMC LOGICAL UNIT NOT SUPPORTED
15 01 DTL WRSOM MECHANICAL POSITIONING ERROR
53 00 DTL WRSOM MEDIA LOAD OR EJECT FAILED
==============================================================================
Table 7-41: ASC and ASCQ Assignments (continued)
==============================================================================
BYTE
12 13 DTLPWRSOMC DESCRIPTION
-- -- ------------------------------------------------------------
3B 0D M MEDIUM DESTINATION ELEMENT FULL
31 00 DT W O MEDIUM FORMAT CORRUPTED
3A 00 DTL WRSOM MEDIUM NOT PRESENT
53 02 DT WR OM MEDIUM REMOVAL PREVENTED
3B 0E M MEDIUM SOURCE ELEMENT EMPTY
43 00 DTLPWRSOMC MESSAGE ERROR
3F 01 DTLPWRSOMC MICROCODE HAS BEEN CHANGED
1D 00 D W O MISCOMPARE DURING VERIFY OPERATION
11 0A DT O MISCORRECTED ERROR
2A 01 DTL WRSOMC MODE PARAMETERS CHANGED
07 00 DTL WRSOM MULTIPLE PERIPHERAL DEVICES SELECTED
11 03 DT W SO MULTIPLE READ ERRORS
00 00 DTLPWRSOMC NO ADDITIONAL SENSE INFORMATION
00 15 R NO CURRENT AUDIO STATUS TO RETURN
32 00 D W O NO DEFECT SPARE LOCATION AVAILABLE
11 09 T NO GAP FOUND
01 00 D W O NO INDEX/SECTOR SIGNAL
06 00 D WR OM NO REFERENCE POSITION FOUND
02 00 D WR OM NO SEEK COMPLETE
03 01 T NO WRITE CURRENT
28 00 DTLPWRSOMC NOT READY TO READY TRANSITION (MEDIUM MAY HAVE CHANGED)
5A 01 DT WR OM OPERATOR MEDIUM REMOVAL REQUEST
5A 00 DTLPWRSOM OPERATOR REQUEST OR STATE CHANGE INPUT (UNSPECIFIED)
5A 03 DT W O OPERATOR SELECTED WRITE PERMIT
5A 02 DT W O OPERATOR SELECTED WRITE PROTECT
61 02 S OUT OF FOCUS
4E 00 DTLPWRSOMC OVERLAPPED COMMANDS ATTEMPTED
2D 00 T OVERWRITE ERROR ON UPDATE IN PLACE
3B 05 L PAPER JAM
1A 00 DTLPWRSOMC PARAMETER LIST LENGTH ERROR
26 01 DTLPWRSOMC PARAMETER NOT SUPPORTED
26 02 DTLPWRSOMC PARAMETER VALUE INVALID
2A 00 DTL WRSOMC PARAMETERS CHANGED
03 00 DTL W SO PERIPHERAL DEVICE WRITE FAULT
50 02 T POSITION ERROR RELATED TO TIMING
3B 0C S POSITION PAST BEGINNING OF MEDIUM
3B 0B S POSITION PAST END OF MEDIUM
15 02 DT WR O POSITIONING ERROR DETECTED BY READ OF MEDIUM
29 00 DTLPWRSOMC POWER ON, RESET, OR BUS DEVICE RESET OCCURRED
42 00 D POWER-ON OR SELF-TEST FAILURE (SHOULD USE 40 NN)
1C 01 D O PRIMARY DEFECT LIST NOT FOUND
40 00 D RAM FAILURE (SHOULD USE 40 NN)
15 00 DTL WRSOM RANDOM POSITIONING ERROR
3B 0A S READ PAST BEGINNING OF MEDIUM
3B 09 S READ PAST END OF MEDIUM
11 01 DT W SO READ RETRIES EXHAUSTED
14 01 DT WR O RECORD NOT FOUND
14 00 DTL WRSO RECORDED ENTITY NOT FOUND
==============================================================================
Table 7-41: ASC and ASCQ Assignments (continued)
==============================================================================
BYTE
12 13 DTLPWRSOMC DESCRIPTION
-- -- ------------------------------------------------------------
18 02 D WR O RECOVERED DATA - DATA AUTO-REALLOCATED
18 05 D WR O RECOVERED DATA - RECOMMEND REASSIGNMENT
17 05 D WR O RECOVERED DATA USING PREVIOUS SECTOR ID
18 03 R RECOVERED DATA WITH CIRC
18 01 D WR O RECOVERED DATA WITH ERROR CORRECTION AND RETRIES APPLIED
18 00 DT WR O RECOVERED DATA WITH ERROR CORRECTION APPLIED
18 04 R RECOVERED DATA WITH LEC
17 03 DT WR O RECOVERED DATA WITH NEGATIVE HEAD OFFSET
17 00 DT WRSO RECOVERED DATA WITH NO ERROR CORRECTION APPLIED
17 02 DT WR O RECOVERED DATA WITH POSITIVE HEAD OFFSET
17 01 DT WRSO RECOVERED DATA WITH RETRIES
17 04 WR O RECOVERED DATA WITH RETRIES AND/OR CIRC APPLIED
17 06 D W O RECOVERED DATA WITHOUT ECC - DATA AUTO-REALLOCATED
17 07 D W O RECOVERED DATA WITHOUT ECC - RECOMMEND REASSIGNMENT
1E 00 D W O RECOVERED ID WITH ECC CORRECTION
3B 08 T REPOSITION ERROR
36 00 L RIBBON, INK, OR TONER FAILURE
37 00 DTL WRSOMC ROUNDED PARAMETER
5C 00 D O RPL STATUS CHANGE
39 00 DTL WRSOMC SAVING PARAMETERS NOT SUPPORTED
62 00 S SCAN HEAD POSITIONING ERROR
47 00 DTLPWRSOMC SCSI PARITY ERROR
54 00 P SCSI TO HOST SYSTEM INTERFACE FAILURE
45 00 DTLPWRSOMC SELECT OR RESELECT FAILURE
3B 00 TL SEQUENTIAL POSITIONING ERROR
00 03 T SETMARK DETECTED
3B 04 L SLEW FAILURE
09 03 WR O SPINDLE SERVO FAILURE
5C 02 D O SPINDLES NOT SYNCHRONIZED
5C 01 D O SPINDLES SYNCHRONIZED
1B 00 DTLPWRSOMC SYNCHRONOUS DATA TRANSFER ERROR
55 00 P SYSTEM RESOURCE FAILURE
33 00 T TAPE LENGTH ERROR
3B 03 L TAPE OR ELECTRONIC VERTICAL FORMS UNIT NOT READY
3B 01 T TAPE POSITION ERROR AT BEGINNING-OF-MEDIUM
3B 02 T TAPE POSITION ERROR AT END-OF-MEDIUM
3F 00 DTLPWRSOMC TARGET OPERATING CONDITIONS HAVE CHANGED
5B 01 DTLPWRSOM THRESHOLD CONDITION MET
26 03 DTLPWRSOMC THRESHOLD PARAMETERS NOT SUPPORTED
2C 01 S TOO MANY WINDOWS SPECIFIED
09 00 DT WR O TRACK FOLLOWING ERROR
09 01 WR O TRACKING SERVO FAILURE
61 01 S UNABLE TO ACQUIRE VIDEO
57 00 R UNABLE TO RECOVER TABLE-OF-CONTENTS
53 01 T UNLOAD TAPE FAILURE
11 00 DT WRSO UNRECOVERED READ ERROR
11 04 D W O UNRECOVERED READ ERROR - AUTO REALLOCATE FAILED
==============================================================================
Table 7-41: ASC and ASCQ Assignments (continued)
==============================================================================
BYTE
12 13 DTLPWRSOMC DESCRIPTION
-- -- ------------------------------------------------------------
11 0B D W O UNRECOVERED READ ERROR - RECOMMEND REASSIGNMENT
11 0C D W O UNRECOVERED READ ERROR - RECOMMEND REWRITE THE DATA
46 00 DTLPWRSOMC UNSUCCESSFUL SOFT RESET
59 00 O UPDATED BLOCK READ
61 00 S VIDEO ACQUISITION ERROR
50 00 T WRITE APPEND ERROR
50 01 T WRITE APPEND POSITION ERROR
0C 00 T S WRITE ERROR
0C 02 D W O WRITE ERROR - AUTO REALLOCATION FAILED
0C 01 D W O WRITE ERROR RECOVERED WITH AUTO REALLOCATION
27 00 DT W O WRITE PROTECTED
------------------------------------------
80 XX \
THROUGH > VENDOR SPECIFIC.
FF XX /
XX 80 \
THROUGH > VENDOR SPECIFIC QUALIFICATION OF STANDARD ASC.
XX FF /
ALL CODES NOT SHOWN ARE RESERVED.
==============================================================================
NOTE: Appendix I contains the ASC and ASCQ assignments in numeric order.
7.2.15. SEND DIAGNOSTIC Command
Table 7-42: SEND DIAGNOSTIC Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (1Dh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | PF |Reserved|SelfTest| DevOfL | UnitOfL|
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | (MSB) |
-----|--- Parameter List Length ---|
4 | (LSB) |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The SEND DIAGNOSTIC command (Table 7-42) requests the target to perform
diagnostic operations on itself, on the logical unit, or on both. The only
mandatory implementation of this command is the self-test feature with the
parameter list length of zero. Except when the self-test bit is one, this
command is usually followed by a RECEIVE DIAGNOSTIC RESULTS command.
A page format (PF) bit of one specifies that the SEND DIAGNOSTIC parameters
conform to the page structure as specified in this standard. The
implementation of the PF bit is optional. See 7.3.1 for the definition of
diagnostic pages. A PF bit of zero indicates that the SEND DIAGNOSTIC
parameters are as specified in SCSI-1 (i.e., all parameters are vendor
specific).
A self-test (SelfTest) bit of one directs the target to complete its default
self-test. If the self-test successfully passes, the command shall be
terminated with GOOD status; otherwise, the command shall be terminated with
CHECK CONDITION status and the sense key shall be set to HARDWARE ERROR.
A self-test bit of zero requests that the target perform the diagnostic
operation specified in the parameter list. The diagnostic operation might or
might not require a target to return data which contains diagnostic results.
If the return of data is not required, the return of GOOD status indicates
successful completion of the diagnostic operation. If the return of data is
required the target shall either:
(1) perform the requested diagnostic operation, prepare the data to be
returned and indicate completion by returning GOOD status. The initiator
issues a RECEIVE DIAGNOSTIC RESULTS command to recover the data.
(2) accept the parameter list and if no errors are detected in the parameter
list return GOOD status. The requested diagnostic operation and the
preparation of the data to be returned is performed upon receipt of a RECEIVE
DIAGNOSTIC RESULTS command.
IMPLEMENTORS NOTE: To insure that the diagnostic command information is not
destroyed by a command sent from another initiator, the SEND DIAGNOSTIC
command should either be linked to the RECEIVE DIAGNOSTIC RESULTS command or
the logical unit should be reserved.
The device off-line (DevOfL) and unit off-line (UnitOfL) bits are generally
set by operating system software, while the parameter list is prepared by
diagnostic application software. These bits grant permission to perform
vendor-specific diagnostic operations on the target which may be visible to
attached initiators. Thus, by preventing operations that are not enabled by
these bits, the target assists the operating system in protecting its
resources.
A UnitOfL bit of one grants permission to the target to perform diagnostic
operations that may affect the user accessible medium on the logical unit,
e.g., write operations to the user accessible medium, or repositioning of the
medium on sequential access devices. The implementation of the UnitOfl bit is
optional. A UnitOfL bit of zero prohibits any diagnostic operations that may
be detected by subsequent I/O processes.
A DevOfl bit of one grants permission to the target to perform diagnostic
operations that may affect all the logical units on a target, e.g., alteration
of reservations, log parameters, or sense data. The implementation of the
DevOfl bit is optional. A DevOfL bit of zero prohibits diagnostic operations
that may be detected by subsequent I/O processes.
The parameter list length field specifies the length in bytes of the
parameter list that shall be transferred from the initiator to the target. A
parameter list length of zero indicates that no data shall be transferred.
This condition shall not be considered as an error. If the specified
parameter list length results in the truncation of one or more pages (PF bit
set to one) the target shall return CHECK CONDITION status with a sense key of
ILLEGAL REQUEST and an additional sense code of INVALID FIELD IN CDB.
See the implementors note under the RECEIVE DIAGNOSTIC RESULTS command in
7.2.13.
7.2.16. TEST UNIT READY Command
Table 7-43: TEST UNIT READY Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (00h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Control |
==============================================================================
The TEST UNIT READY command (Table 7-43) provides a means to check if the
logical unit is ready. This is not a request for a self-test. If the logical
unit would accept an appropriate medium-access command without returning CHECK
CONDITION status, this command shall return a GOOD status. If the logical
unit cannot become operational or is in a state such that an initiator action
(e.g., START UNIT command) is required to make the unit ready the target shall
return CHECK CONDITION status with a sense key of NOT READY.
Table 7-44 defines the preferred responses to the TEST UNIT READY command.
Higher-priority responses (e.g., BUSY or RESERVATION CONFLICT) are also
permitted.
Table 7-44: Preferred TEST UNIT READY Responses
==============================================================================
Status Sense Key Additional Sense Code and
Additional Sense Code Qualifier
--------------- --------------- --------------------------------------------
GOOD NO SENSE NO ADDITIONAL SENSE INFORMATION or other
valid additional sense code.
CHECK CONDITION ILLEGAL REQUEST LOGICAL UNIT NOT SUPPORTED
CHECK CONDITION NOT READY LOGICAL UNIT DOES NOT RESPOND TO SELECTION
CHECK CONDITION NOT READY MEDIUM NOT PRESENT
CHECK CONDITION NOT READY LOGICAL UNIT NOT READY, CAUSE NOT REPORTABLE
CHECK CONDITION NOT READY LOGICAL UNIT IS IN PROCESS OF BECOMING READY
CHECK CONDITION NOT READY LOGICAL UNIT NOT READY, INITIALIZING COMMAND
REQUIRED
CHECK CONDITION NOT READY LOGICAL UNIT NOT READY, MANUAL INTERVENTION
REQUIRED
CHECK CONDITION NOT READY LOGICAL UNIT NOT READY, FORMAT IN PROGRESS
==============================================================================
7.2.17. WRITE BUFFER Command
Table 7-45: WRITE BUFFER Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (3Bh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | Mode |
-----|-----------------------------------------------------------------------|
2 | Buffer ID |
-----|-----------------------------------------------------------------------|
3 | (MSB) |
- - -|- - Buffer Offset - -|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
- - -|- - Parameter List Length - -|
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The WRITE BUFFER command (Table 7-45) is used in conjunction with the READ
BUFFER command as a diagnostic for testing target memory and the SCSI bus
integrity. Additional modes are provided for downloading microcode and for
downloading and saving microcode.
This command shall not alter any medium of the target when the data mode or
the combined header and data mode is specified.
The function of this command and the meaning of fields within the command
descriptor block depend on the contents of the mode field. The mode field is
defined in Table 7-46.
Table 7-46: WRITE BUFFER Mode Field
=======================================================
Implementation
Mode Description Requirements
---- ------------------------------ ---------------
000b Write combined header and data Optional
001b Vendor specific Vendor specific
010b Write data Optional
011b Reserved Reserved
100b Download Microcode Optional
101b Download Microcode and Save Optional
110b Reserved Reserved
111b Reserved Reserved
=======================================================
IMPLEMENTORS NOTE: Modes 000b and 001b are included for compatibility with
CCS products that were designed prior to the generation of this standard.
These products restrict the maximum transfer length to 65535 bytes.
7.2.17.1. Combined Header and Data Mode (000b)
In this mode, data to be transferred is preceded by a four-byte header. The
four-byte header consists of all reserved bytes. The buffer ID and the buffer
offset fields shall be zero. The parameter list length field specifies the
maximum number of bytes that shall be transferred during the DATA OUT phase.
This number includes four bytes of header, so the data length to be stored in
the target's buffer is parameter list length minus four. The initiator should
attempt to ensure that the parameter list length is not greater than four plus
the available length that is returned in the header of the READ BUFFER command
(mode 00b). If the parameter list length exceeds the available length plus
four, the target shall return CHECK CONDITION status and shall set the sense
key to ILLEGAL REQUEST.
7.2.17.2. Vendor-Specific Mode (001b)
In this mode, the meaning of the buffer ID, buffer offset, and parameter
list length fields are not specified by this standard.
7.2.17.3. Data Mode (010b)
In this mode, the DATA OUT phase contains buffer data. The buffer ID field
identifies a specific buffer within the target. The vendor assigns buffer ID
codes to buffers within the target. Buffer ID zero shall be supported. If
more than one buffer is supported, additional buffer ID codes shall be
assigned contiguously, beginning with one. If an unsupported buffer ID code
is selected, the target shall return CHECK CONDITION status and shall set the
sense key to ILLEGAL REQUEST with an additional sense code of INVALID FIELD IN
CDB.
Data is written to the target buffer starting at the location specified by
the buffer offset. The initiator should conform to the offset boundary
requirements returned in the READ BUFFER descriptor. If the target is unable
to accept the specified buffer offset, it shall return CHECK CONDITION status
and it shall set the sense key to ILLEGAL REQUEST with an additional sense
code of INVALID FIELD IN CDB.
The parameter list length specifies the maximum number of bytes that shall
be transferred during the DATA OUT phase to be stored in the specified buffer
beginning at the buffer offset. The initiator should attempt to ensure that
the parameter list length plus the buffer offset does not exceed the capacity
of the specified buffer. (The capacity of the buffer can be determined by the
buffer capacity field in the READ BUFFER descriptor.) If the buffer offset
and parameter list length fields specify a transfer that would exceed the
buffer capacity, the target shall return CHECK CONDITION status and shall set
the sense key to ILLEGAL REQUEST with an additional sense code of INVALID
FIELD IN CDB.
7.2.17.4. Download Microcode Mode (100b)
In this mode, vendor-specific microcode or control information shall be
transferred to the control memory space of the target. After a power-cycle or
reset, the device operation shall revert to a vendor-specific condition. The
meanings of the buffer ID, buffer offset, and parameter list length fields are
not specified by this standard and are not required to be zero-filled. When
the microcode download has completed successfully the target shall generate a
unit attention condition for all initiators except the one that issued the
WRITE BUFFER command (see 6.9). The additional sense code shall be set to
MICROCODE HAS BEEN CHANGED.
7.2.17.5. Download Microcode and Save Mode (101b)
In this mode, vendor-specific microcode or control information shall be
transferred to the target and, if the WRITE BUFFER command is completed
successfully, also shall be saved in a non-volatile memory space
(semiconductor, disk, or other). The downloaded code shall then be effective
after each power-cycle and reset until it is supplanted in another download
microcode and save operation. The meanings of the buffer ID, buffer offset,
and parameter list length fields are not specified by this standard and are
not required to be zero-filled. When the download microcode and save command
has completed successfully the target shall generate a unit attention
condition for all initiators except the one that issued the WRITE BUFFER
command. When reporting the unit attention condition, the target shall set
the additional sense code to MICROCODE HAS BEEN CHANGED.
7.3. Parameters for All Device Types
7.3.1. Diagnostic Parameters
This section describes the diagnostic page structure and the diagnostic
pages that are applicable to all SCSI devices. Pages specific to each device
type are described in the third subsection of each device-type section (i.e.,
8.3, 9.3, etc.).
A SEND DIAGNOSTIC command with a PF bit of one specifies that the SEND
DIAGNOSTIC parameter list consists of zero or more diagnostic pages and that
the data returned by the subsequent RECEIVE DIAGNOSTIC RESULTS command shall
use the diagnostic page format (Table 7-47) described in this standard.
Each diagnostic page defines a function or operation that the target shall
perform. The page contains a page header followed by the analysis data which
is formatted according to the page code specified in the previous SEND
DIAGNOSTIC command.
Targets that implement diagnostic pages are only required to accept a single
diagnostic page per command.
Table 7-47: Diagnostic Page Format
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Page Code |
-----|-----------------------------------------------------------------------|
1 | Reserved |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- Page Length (n-3) ---|
3 | (LSB) |
-----|-----------------------------------------------------------------------|
4 | |
- - -|- - Diagnostic Parameters - -|
n | |
==============================================================================
The page code field identifies which diagnostic page is being sent or
returned. The page codes are defined in Table 7-48.
The page length field specifies the length in bytes of the diagnostic
parameters which follow this field. If the initiator sends a page length that
results in the truncation of any parameter, the target shall terminate the
command with CHECK CONDITION status. The sense key shall be set to ILLEGAL
REQUEST with the additional sense code set to INVALID FIELD IN PARAMETER LIST.
The diagnostic parameters are defined for each page code. The diagnostic
parameters within a page may be defined differently in a SEND DIAGNOSTIC
command than in a RECEIVE DIAGNOSTIC RESULTS command.
Table 7-48: Diagnostic Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
00h Supported Diagnostics Pages 7.3.1.1
01h - 3Fh Reserved (for all device type pages)
40h - 7Fh See specific device type for definition
80h - FFh Vendor specific pages
==============================================================================
7.3.1.1. Supported Diagnostic Pages
The supported diagnostics page (Table 7-49) returns the list of diagnostic
pages implemented by the target. This page shall be implemented if the target
implements the page format option of the SEND DIAGNOSTIC and RECEIVE
DIAGNOSTIC RESULTS commands.
Table 7-49: Supported Diagnostic Pages
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Page Code (00h) |
-----|-----------------------------------------------------------------------|
1 | Reserved |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- Page Length (n-3) ---|
3 | (LSB) |
-----|-----------------------------------------------------------------------|
4 | |
- - -|- - Supported Page List - -|
n | |
==============================================================================
The definition of this page for the SEND DIAGNOSTIC command includes only
the first four bytes. If the page length field is not zero, the target shall
terminate the SEND DIAGNOSTIC command with CHECK CONDITION status. The sense
key shall be set to ILLEGAL REQUEST with an additional sense code of INVALID
FIELD IN PARAMETER LIST. This page instructs the target to make available the
list of all supported diagnostic pages to be returned by a subsequent RECEIVE
DIAGNOSTIC RESULTS command.
The definition of this page for the RECEIVE DIAGNOSTIC RESULTS command
includes the list of diagnostic pages supported by the target.
The page length field specifies the length in bytes of the following
supported page list.
The supported page list field shall contain a list of all diagnostic page
codes implemented by the target in ascending order beginning with page code
00h.
7.3.2. Log Parameters
This section describes the log page structure and the log pages that are
applicable to all SCSI devices. Pages specific to each device type are
described in the third subsection of each device-type section (i.e., 8.3.2,
9.3.2, etc.). The LOG SELECT command supports the ability to send zero or
more log pages. The LOG SENSE command returns a single log page specified in
the page code field of the command descriptor block (see Table 7-21).
Each log page begins with a four-byte page header followed by zero or more
variable-length log parameters defined for that page. The log page format is
defined in Table 7-50.
Table 7-50: Log Page Format
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Reserved | Page Code |
-----|-----------------------------------------------------------------------|
1 | Reserved |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- Page Length (n-3) ---|
3 | (LSB) |
==============================================================================
| Log Parameters(s) |
==============================================================================
4 - | Log Parameter (First) |
x+3 | (Length x) |
-----|-----------------------------------------------------------------------|
| . |
| . |
| . |
-----|-----------------------------------------------------------------------|
n-y | Log Parameter (Last) |
n | (Length y) |
==============================================================================
The page code field identifies which log page is being transferred.
The page length field specifies the length in bytes of the following log
parameters. If the initiator sends a page length that results in the
truncation of any parameter, the target shall terminate the command with CHECK
CONDITION status. The sense key shall be set to ILLEGAL REQUEST with the
additional sense code set to INVALID FIELD IN PARAMETER LIST.
Most log pages contain one or more special data structures called log
parameters (see Table 7-51). Log parameters may be data counters which record
a count of a particular event (or events) or log parameters may be list
parameters (strings) which contain a description of a particular event.
Table 7-51: Log Parameter
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | (MSB) |
-----|--- Parameter Code ---|
1 | (LSB) |
-----|-----------------------------------------------------------------------|
2 | DU | DS | TSD | ETC | TMC |Reserved| LP |
-----|-----------------------------------------------------------------------|
3 | Parameter Length (n-3) |
-----|-----------------------------------------------------------------------|
4 | |
- - -|- - Parameter Value - -|
n | |
==============================================================================
Each log parameter (Table 7-51) begins with a four-byte parameter header
followed by one or more bytes of parameter value data.
The parameter code field identifies which log parameter is being transferred
for that log page.
The DU, DS, TSD, ETC, TMC, and LP fields are collectively referred to as the
parameter control byte. These fields are described below.
For cumulative log parameter values (indicated by the PC field of the LOG
SELECT and LOG SENSE command descriptor block), the disable update (DU) bit is
defined as follows:
(1) A zero value indicates that the target shall update the log parameter
value to reflect all events that should be noted by that parameter.
(2) A one value indicates that the target shall not update the log parameter
value except in response to a LOG SELECT command that specifies a new value
for the parameter.
IMPLEMENTORS NOTE: When updating cumulative log parameter values, a target
may use volatile memory to hold these values until a LOG SELECT or LOG SENSE
command is received with an SP bit of one (or a target-defined event
occurs). Thus the updated cumulative log parameter values may be lost if a
power cycle occurs.
The DU bit is not defined for threshold values (indicated by the PC field of
the LOG SENSE command descriptor block) nor for list parameters (indicated by
the LP bit). The target shall ignore the value of any DU bits in a LOG SELECT
command.
A disable save (DS) bit of zero indicates that the target supports saving
for that log parameter. The target shall save the current cumulative or the
current threshold parameter value (depending on the value in the PC field of
the command descriptor block) in response to a LOG SELECT or LOG SENSE command
with a SP bit of one. A DS bit of one indicates that the target does not
support saving that log parameter in response to a LOG SELECT or LOG SENSE
command with a SP bit of one.
A target save disable (TSD) bit of zero indicates that the target provides a
target-defined method for saving log parameters. This implicit saving
operation shall be done frequently enough to insure that the cumulative
parameter values retain statistical significance (i.e., across power cycles).
A TSD bit of one indicates that either the target does not provide a target-
defined method for saving log parameters or the target-defined method has been
disabled by the initiator. If the initiator sets both the DS and the TSD bits
set to one, the target shall terminate the command with CHECK CONDITION
status. The sense key shall be set to ILLEGAL REQUEST with the additional
sense code set to INVALID FIELD IN PARAMETER LIST.
An enable threshold comparison (ETC) bit of one indicates that a comparison
to the threshold value is performed whenever the cumulative value is updated.
An ETC bit of zero indicates that a comparison is not performed. The value of
the ETC bit is the same for cumulative and threshold parameters.
The threshold met criteria (TMC) field (Table 7-52) defines the basis for
comparison of the cumulative and threshold values. The TMC field is valid
only if the ETC bit is one. The value of the TMC field is the same for
cumulative and threshold parameters.
If the ETC bit is one and the result of the comparison is true, a unit
attention condition shall be generated for all initiators. When reporting the
unit attention condition, the target shall set The sense key shall be set to
UNIT ATTENTION; the additional sense code shall be set to LOG EXCEPTION; and
the additional sense code qualifier set to THRESHOLD CONDITION MET.
Table 7-52: Threshold Met Criteria
===================================================
Code Basis For Comparison
--- ---------------------------------------------
00b Every update of the cumulative value
01b Cumulative value equal threshold value
10b Cumulative value not equal threshold value
11b Cumulative value greater than threshold value
===================================================
The list parameter (LP) bit indicates the format of the log parameter. If
an initiator attempts to set the value of the LP bit to a value other than the
one returned for the same parameter in the LOG SENSE command, the target shall
terminate the command with CHECK CONDITION status. The sense key shall be set
to ILLEGAL REQUEST with the additional sense code set to INVALID FIELD IN
PARAMETER LIST.
An LP bit of zero indicates that the parameter is a data counter. Data
counters are associated with one of more events. The data counter is updated
whenever one of these events occurs by incrementing of the counter value
provided the DU bit is zero. Each data counter has associated with it a
target-defined maximum value. Upon reaching this maximum value, the data
counter shall not be incremented (i.e., it does not wrap). When a data
counter reaches its maximum value, the target shall set the associated DU bit
to one. If the data counter is at or reaches its maximum value during the
execution of a command, the target shall complete the command. If the command
completes correctly (except for the data counter being at its maximum value)
and if the RLEC bit of the control mode page (7.3.3.1) is set to one, then the
target shall terminate the command with CHECK CONDITION status and set the
sense key to RECOVERED ERROR with the additional sense code set to LOG COUNTER
AT MAXIMUM.
An LP bit of one indicates that the parameter is a list parameter. List
parameters are not counters and thus the ET and TMC fields shall be set to
zero. A list parameter is a string of ASCII graphic codes (i.e., code values
20h through 7Eh).
If more than one list parameter is defined in a single log page, the
following rules apply to assigning parameter codes:
(1) The parameter updated last shall have a higher parameter code than the
previous parameter, except as defined in rule (2).
(2) When the maximum parameter code value supported by the target is
reached, the target shall assign the lowest parameter code value to the next
log parameter (i.e., wrap-around parameter codes). If the associated command
completes correctly (except for the parameter code being at its maximum value)
and if the RLEC bit of the control mode page (7.3.3.1) is set to one, then the
target shall terminate the command with CHECK CONDITION status and set the
sense key to RECOVERED ERROR with the additional sense code set to LOG LIST
CODES EXHAUSTED.
IMPLEMENTORS NOTE: List parameters can be used to store the locations of
defective blocks in the following manner. When a defective block is
identified, a list parameter is updated to reflect the location and cause of
the defect. When the next defect is encountered, the list parameter with
the next higher parameter code is updated to record this defect. The size
of the page can be made target specific to accommodate memory limitations.
It is recommended that one or more data counter parameters be defined for
the page to keep track of the number of valid list parameters and the
parameter code of the parameter with the oldest recorded defect. This
technique can be adapted to record other types of information.
The parameter length field specifies the length in bytes of the following
parameter value. If the initiator sends a parameter length value that results
in the truncation of the parameter value, the target shall terminate the
command with CHECK CONDITION status. The sense key shall be set to ILLEGAL
REQUEST with the additional sense code set to INVALID FIELD IN PARAMETER LIST.
If the initiator sends a log parameter value that is outside the range
supported by the target and rounding is implemented for that parameter, the
target may either:
(1) round to an acceptable value and terminate the command as described in
6.5.4.
(2) terminate the command with CHECK CONDITION status, set the sense key to
ILLEGAL REQUEST with the additional sense code set to INVALID FIELD IN
PARAMETER LIST.
When any counter in a log page reaches its maximum value, incrementing of
all counters in that log page shall cease until re-initialized by the
initiator via a LOG SELECT command. If the RLEC bit of the control mode page
is one, then the target shall report the exception condition as described in
7.3.3.1.
The page code assignments for the log pages are listed in Table 7-53.
Table 7-53: Log Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
01h Buffer Over-Run/Under-Run Page 7.3.2.1
03h Error Counter Page (Read) Page 7.3.2.2
04h Error Counter Page (Read Reverse) Page 7.3.2.2
05h Error Counter Page (Verify) Page 7.3.2.2
02h Error Counter Page (Write) Page 7.3.2.2
07h Last n Error Events Page 7.3.2.3
06h Non-Medium Error Page 7.3.2.4
00h Supported Log Pages 7.3.2.5
08h - 2Fh Reserved
3Fh Reserved
30h - 3Eh Vendor Specific
==============================================================================
7.3.2.1. Buffer Over-Run/Under-Run Page
The buffer over-run/under-run page (page code 01h) defines 24 data counters
that may be used to record the number of buffer over-runs or under-runs for
the logical unit. A target that implements this page may implement one or
more of the defined data counters.
A buffer over-run or under-run can occur when an initiator does not transmit
data to or from the target's buffer fast enough to keep up with reading or
writing the media. This can be caused by a slow transfer rate across the SCSI
bus or by a high SCSI bus utilization that prevents reconnection by the
target. A buffer over-run condition can occur during a read operation when a
buffer full condition prevents continued transfer of data from the media to
the buffer. A buffer under-run condition can occur during a write operation
when a buffer empty condition prevents continued transfer of data to the media
from the buffer. Most devices incur a delay at this point while the media is
repositioned.
Table 7-54 defines the parameter code field for the buffer over-run/under-
run counters.
Table 7-54: Parameter Code Field for Buffer Over-Run/Under-Run Counters
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Reserved |
-----|-----------------------------------------------------------------------|
1 | Count Basis | Cause | Type |
==============================================================================
The parameter code field for buffer over-run/under-run counters is a 16-bit
value comprised of eight reserved bits, a three-bit count basis field (Table
7-55), a four-bit cause field (Table 7-56), and a one-bit type field. These
are concatenated to determine the value of the parameter code for that log
parameter. For example, a parameter code value of 0023h specifies a count
basis of 001b, a cause of 0001b, and a type of 1b which is a counter that is
incremented once per command that experiences an over-run due to the SCSI bus
being busy.
The count basis field defines the criteria for incrementing the counter.
The following criteria are defined:
Table 7-55: Count Basis Definition
================================================
Count Basis Description
----------- -----------------------------------
000b Undefined
001b Per Command
010b Per Failed Reconnect
011b Per Unit of Time
100b-111b Reserved
================================================
IMPLEMENTORS NOTE: The per unit of time count basis is device type
specific. Direct-access devices typically use a latency period (i.e., one
revolution of the medium) as the unit of time.
The cause field indicates the reason that the over-run or under-run
occurred. The following causes are defined:
Table 7-56: Cause Field Definition
=================================
Cause Description
------- ----------------------
0h Undefined
1h SCSI Bus Busy
2h Transfer Rate Too Slow
3h-Fh Reserved
=================================
The type field indicates whether the counter records under-runs or over-
runs. A value of zero specifies a buffer under-run condition and a value of
one specifies a buffer over-run condition.
The counters contain the total number of times buffer over-run or under- run
conditions have occurred since the last time the counter was cleared. The
counter shall be incremented for each occurrence of an under-run or over-run
condition and can be incremented more than once for multiple occurrences
during the execution of a single command.
7.3.2.2. Error Counter Pages
This section defines the optional error counter pages for write errors (page
code 02h), read errors (page code 03h), read reverse errors (page code 04h)
and verify errors (page code 05h). Table 7-50 defines the page format for
these pages. A page can return one or more log parameters which record events
defined by the parameter codes (Table 7-57).
Table 7-57 defines the parameter codes for the error counter pages. Support
of each log parameter is optional.
Table 7-57: Parameter Codes for Error Counter Pages
======================================================
Parameter
Code Description
---------- ------------------------------------------
0000h Errors corrected without substantial delay
0001h Errors corrected with possible delays
0002h Total (e.g., re-writes or re-reads)
0003h Total errors corrected
0004h Total times correction algorithm processed
0005h Total bytes processed
0006h Total uncorrected errors
0007-7FFFh Reserved
8000-FFFFh Vendor specific
======================================================
IMPLEMENTORS NOTE: The exact definition of the error counters is not part
of this standard. These counters should not be used to compare products
because the products may define errors differently.
7.3.2.3. Last n Error Events Page
Log page (07h) provides for a number of error-event records using the list
parameter format of the log page. The number of these error-event records
supported, n, is device-specific. Each error-event record contains device-
specific diagnostic information for a single error encountered by the device.
The parameter code associated with error-event record indicates the relative
time at which the error occurred. A higher parameter code indicates that the
error event occurred later in time.
The content of the parameter value field of each log parameter is an ASCII
character string which may describe the error event. The exact contents of
the character string is not defined by this standard.
When the last supported parameter code is used by an error-event record, the
recording on this page of all subsequent error information shall cease until
one or more of the list parameters with the highest parameter codes have been
re-initialized. If the RLEC bit of the common mode (7.3.3.1) is set to one,
the target shall return CHECK CONDITION status with the sense key set to
RECOVERED ERROR and the additional sense code set to LOG LIST CODES EXHAUSTED.
Alternatively, the target may report this condition via asynchronous event
notification (see 6.5.5).
7.3.2.4. Non-Medium Error Page
This page (page code 06h) provides for summing the occurrences of
recoverable error events other than write, read, or verify failures. No
discrimination among the various types of events is provided by parameter code
(Table 7-58). Vendor-specific discrimination may be provided through the
vendor-specific parameter codes.
Table 7-58: Non-Medium Error Event Parameter Codes
==============================================
Parameter Code Description
-------------- ------------------------------
0000h Non-Medium Error Count
0001h - 7FFFh Reserved
8000h - FFFFh Vendor-Specific Error Counts
==============================================
7.3.2.5. Supported Log Pages
The supported log page (Table 7-59) returns the list of log pages
implemented by the target. Targets that implement the LOG SENSE command shall
implement this log page.
Table 7-59: Supported Log Pages
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Reserved | Page Code (00h) |
-----|-----------------------------------------------------------------------|
1 | Reserved |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- Page Length (n-3) ---|
3 | (LSB) |
-----|-----------------------------------------------------------------------|
4 | |
- - -|- - Supported Page List - -|
n | |
==============================================================================
This page is not defined for the LOG SELECT command. This log page returns
the list of supported log pages for the specified logical unit.
The page length field specifies the length in bytes of the following
supported page list.
The supported page list field shall contain a list of all log page codes
implemented by the target in ascending order beginning with page code 00h.
7.3.3. Mode Parameters
This section describes the block descriptors and the pages used with MODE
SELECT and MODE SENSE commands that are applicable to all SCSI devices. Pages
specific to each device type are described in the third subsection of each
device-type section (i.e., 8.3, 9.3, etc.).
The mode parameter list shown in Table 7-60 contains a header, followed by
zero or more block descriptors, followed by zero or more variable-length
pages. Parameter lists are defined for each device type.
Table 7-60: Mode Parameter List
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 - n| Mode Parameter Header |
==============================================================================
0 - n| Block Descriptor(s) |
==============================================================================
0 - n| Page(s) |
==============================================================================
The six-byte command descriptor block parameter header is defined in Table
7-61. The ten-byte command descriptor block parameter header is defined in
Table 7-62.
Table 7-61: Mode Parameter Header(6)
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Mode Data Length |
-----|-----------------------------------------------------------------------|
1 | Medium Type |
-----|-----------------------------------------------------------------------|
2 | Device-Specific Parameter |
-----|-----------------------------------------------------------------------|
3 | Block Descriptor Length |
==============================================================================
Table 7-62: Mode Parameter Header(10)
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | (MSB) |
-----|--- Mode Data Length ---|
1 | (LSB) |
-----|-----------------------------------------------------------------------|
2 | Medium Type |
-----|-----------------------------------------------------------------------|
3 | Device-Specific Parameter |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- Block Descriptor Length ---|
7 | (LSB) |
==============================================================================
When using the MODE SENSE command, the mode data length field specifies the
length in bytes of the following data that is available to be transferred.
The mode data length does not include itself. When using the MODE SELECT
command, this field is reserved.
IMPLEMENTORS NOTE: Targets that support more than 256 bytes of block
descriptors and pages may need to implement ten-byte mode commands. The
mode data length field in the six-byte command descriptor block header
limits the returned data to 256 bytes.
Medium types are unique for each device type. Refer to the mode parameters
section of the specific device type for definition of these values. Some
device types reserve this field.
The device specific parameter is unique for each device type. Refer to the
mode parameters section of the specific device type for definition of this
field. Some device types reserve all or part of this field.
The block descriptor length specifies the length in bytes of all the block
descriptors. It is equal to the number of block descriptors times eight and
does not include pages or vendor-specific parameters, if any, that may follow
the last block descriptor. A block descriptor length of zero indicates that
no block descriptors are included in the mode parameter list. This condition
shall not be considered an error.
The mode parameter block descriptor is shown in Table 7-63.
Table 7-63: Mode Parameter Block Descriptor
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Density Code |
-----|-----------------------------------------------------------------------|
1 | (MSB) |
-----|--- ---|
2 | Number of Blocks |
-----|--- ---|
3 | (LSB) |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | (MSB) |
-----|--- ---|
6 | Block Length |
-----|--- ---|
7 | (LSB) |
==============================================================================
Block descriptors specify some of the medium characteristics for all or part
of a logical unit. Support for block descriptors is optional. Each block
descriptor contains a density code field, a number of blocks field, and a
block length field. Block descriptor values are always current (i.e., saving
is not supported). A unit attention condition (see 6.9) shall be generated
when any block descriptor values are changed.
The density code field is unique for each device type. Refer to the mode
parameters section of the specific device type for definition of this field.
Some device types reserve all or part of this field.
The number of blocks field specifies the number of logical blocks on the
medium to which the density code and block length fields apply. A value of
zero indicates that all of the remaining logical blocks of the logical unit
shall have the medium characteristics specified.
IMPLEMENTORS NOTES:
(1) There may be implicit association between parameters defined in the
pages and block descriptors. For direct-access devices, the block length
affects the optimum values (the values that achieve best performance) for
the sectors per track, bytes per physical sector, track skew factor, and
cylinder skew factor fields in the format parameters page. In this case,
the target may change parameters not explicitly sent with the MODE SELECT
command. A subsequent MODE SENSE command would reflect these changes.
(2) The number of remaining logical blocks may be unknown for some device
types.
The block length specifies the length in bytes of each logical block
described by the block descriptor. For sequential-access devices, a block
length of zero indicates that the logical block size written to the medium is
specified by the transfer length field in the command descriptor block (see
9.2.5 and 9.2.15)
The mode page format is defined in Table 7-64.
Table 7-64: Mode Page Format
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | PS |Reserved| Page Code |
-----|-----------------------------------------------------------------------|
1 | Page Length |
-----|-----------------------------------------------------------------------|
2 - n| Mode Parameters |
==============================================================================
Each mode page contains a page code, a page length, and a set of mode
parameters. The page codes are defined in Table 7-65 and in the mode
parameter sub-sections of the specific device type.
When using the MODE SENSE command, a parameters savable (PS) bit of one
indicates that the mode page can be saved by the target in a non-volatile,
vendor-specific location. A PS bit of zero indicates that the supported
parameters cannot be saved. When using the MODE SELECT command, the PS bit is
reserved.
The page code field identifies the format and parameters defined for that
mode page. Some page codes are defined as applying to all device types (Table
7-65) and other page codes are defined for the specific device type.
When using the MODE SENSE command, if page code 00h (vendor-specific page)
is implemented, the target shall return that page last in response to a
request to return all pages (page code 3Fh). When using the MODE SELECT
command, this page should be sent last.
The page length field specifies the length in bytes of the mode parameters
that follow. If the initiator does not set this value to the value that is
returned for the page by the MODE SENSE command, the target shall terminate
the command with CHECK CONDITION status. The sense key shall be set to to
ILLEGAL REQUEST with the additional sense code set to INVALID FIELD IN
PARAMETER LIST. The target is permitted to implement a mode page that is less
than the full page length defined by this standard, provided no field is
truncated and the page length field correctly specifies the actual length
implemented.
The mode parameters for each page are defined in the following sub-sections
or in the mode parameters sub-section for the specific device type. Mode
parameters not implemented by the target shall be set to zero.
Table 7-65 defines the mode pages that are applicable to all device types
that include the MODE SELECT and MODE SENSE commands.
Table 7-65: Mode Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
0Ah Control Mode Page 7.3.3.1
02h Disconnect-Reconnect Page 7.3.3.2
09h Peripheral Device Page 7.3.3.3
01h (See specific device type)
03h - 08h (See specific device type)
0Bh - 1Fh (See specific device type)
00h Vendor specific (does not require page format)
20h - 3Eh Vendor specific (page format required)
3Fh Return all pages (valid only for the MODE SENSE command)
==============================================================================
7.3.3.1. Control Mode Page
Table 7-66: Control Mode Page
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | PS |Reserved| Page Code (0Ah) |
-----|-----------------------------------------------------------------------|
1 | Page Length (06h) |
-----|-----------------------------------------------------------------------|
2 | Reserved | RLEC |
-----|-----------------------------------------------------------------------|
3 | Queue Algorithm Modifier | Reserved | QErr | DQue |
-----|-----------------------------------------------------------------------|
4 | EECA | Reserved | RAENP | UAAENP | EAENP |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | |
-----|--- Ready AEN Holdoff Period ---|
7 | |
==============================================================================
The control mode page (Table 7-66) provides controls over several SCSI-2
features which are applicable to all device types such as tagged queuing,
extended contingent allegiance, asynchronous event notification, and error
logging.
A report log exception condition (RLEC) bit of one specifies that the target
shall report log exception conditions as described in 7.3.2. A RLEC bit of
zero specifies that the target shall not report log exception conditions.
The queue algorithm modifier field (Table 7-67) specifies restrictions on
the algorithm used for re-ordering commands that are tagged with the SIMPLE
QUEUE TAG message.
Table 7-67: Queue Algorithm Modifier
===============================================
Value Definition
------- --------------------------------
0h Restricted re-ordering
1h Unrestricted re-ordering allowed
2h - 7h Reserved
8h - Fh Vendor specific
===============================================
A value of zero in this field specifies that the target shall order the
actual execution sequence of the queued commands from each initiator such that
data integrity is maintained for that initiator. This means that, if the
transmission of new commands was halted at any time, the final value of all
data observable on the medium shall have exactly the same value as it would
have if the commands had been executed in the same received sequence without
tagged queuing. The restricted reordering value shall be the default value.
A value of one in this field specifies that the target may re-order the
actual execution sequence of the queued commands in any manner it selects.
Any data integrity exposures related to command sequence order are explicitly
handled by the initiator through the selection of appropriate commands and
queue tag messages.
A queue error management (QErr) bit of zero specifies that those commands
still queued after the target has entered the contingent allegiance or
extended contingent allegiance conditions shall continue execution in a normal
manner when that condition has terminated (see 6.8). A QErr bit of one
specifies that those commands still queued after the target has entered the
contingent allegiance or extended contingent allegiance conditions shall be
aborted when that condition has terminated. A unit attention condition shall
be generated for each initiator which had commands in the queue except the
initiator that received the original INITIATE RECOVERY message. When
reporting the unit attention condition, the target shall set the additional
sense code to TAGGED COMMANDS CLEARED BY ANOTHER INITIATOR.
A disable queuing (DQue) bit of zero specifies that tagged queuing shall be
enabled if the target supports tagged queuing. A DQue bit of one specifies
that tagged queuing shall be disabled. Any queued commands for that I_T_x
nexus shall be aborted. Any subsequent queue tag message received shall be
rejected with a MESSAGE REJECT message and the I/O process shall be executed
as an untagged command (see 6.8.1).
An enable extended contingent allegiance (EECA) bit of one specifies that
extended contingent allegiance is enabled (see 6.7). An EECA bit of zero
specifies that extended contingent allegiance is disabled.
The RAENP, UAAENP, and EAENP bits enable specific events to be reported via
the asynchronous event notification protocol. When all three bits are zero,
the target shall not create asynchronous event notifications.
A ready AEN permission (RAENP) bit of one specifies that the target may
issue an asynchronous event notification upon completing its initialization
sequence instead of generating a unit attention condition. A RAENP bit of
zero specifies that the target shall not issue an asynchronous event
notification upon completing its initialization sequence.
IMPLEMENTORS NOTE: If the target's default value for the RAENP bit is one
and it does not implement saved parameters or include a hardware switch,
then it may not be possible to disable the initialization sequence
asynchronous event notification.
A unit attention AEN permission (UAAENP) bit of one specifies that the
target may issue an asynchronous event notification instead of creating a unit
attention condition upon detecting an event which would cause a unit attention
condition (other than upon completing an initialization sequence). A UAAENP
bit of zero specifies that the target shall not issue an asynchronous event
notification instead of creating a unit attention condition.
An error AEN permission (EAENP) bit of one specifies that the target may
issue an asynchronous event notification upon detecting a deferred error
condition instead of waiting to report the deferred error on the next command.
An EAENP bit of zero specifies that the target shall not report deferred error
conditions via an asynchronous event notification.
The ready AEN holdoff period field specifies the minimum time in
milliseconds after the target starts its initialization sequence that it shall
delay before attempting to issue an asynchronous event notification. This
value may be rounded up as defined in 6.5.4.
7.3.3.2. Disconnect-Reconnect Page
Table 7-68: Disconnect-Reconnect Page
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | PS |Reserved| Page Code (02h) |
-----|-----------------------------------------------------------------------|
1 | Page Length (0Eh) |
-----|-----------------------------------------------------------------------|
2 | Buffer Full Ratio |
-----|-----------------------------------------------------------------------|
3 | Buffer Empty Ratio |
-----|-+---------------------------------------------------------------------|
4 | (MSB) |
-----|--- Bus Inactivity Limit ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- Disconnect Time Limit ---|
7 | (LSB) |
-----|-+---------------------------------------------------------------------|
8 | (MSB) |
-----|--- Connect Time Limit ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | (MSB) |
-----|--- Maximum Burst Size ---|
11 | (LSB) |
-----|-----------------------------------------------------------------------|
12 | Reserved | DTDC |
-----|-----------------------------------------------------------------------|
13 | Reserved |
-----|-----------------------------------------------------------------------|
14 | Reserved |
-----|-----------------------------------------------------------------------|
15 | Reserved |
==============================================================================
The disconnect-reconnect page (Table 7-68) provides the initiator the means
to tune the performance of the SCSI bus.
The buffer full ratio field indicates to the target, on read operations, how
full the buffer should be prior to attempting a reselection. Targets that do
not implement the requested ratio should round down to the nearest implemented
ratio as defined in 6.5.4.
The buffer empty ratio field indicates to the target, on write operations,
how empty the buffer should be prior to attempting a reselection. Targets
that do not implement the requested ratio should round down to the nearest
implemented ratio as defined in 6.5.4.
The buffer full and buffer empty ratios are numerators of a fractional
multiplier that has 256 as its denominator. A value of zero indicates that
the target determines when to initiate reselection consistent with the
disconnect time limit parameter. These parameters are advisory to the target.
IMPLEMENTORS NOTE: As an example, consider a target with ten 512-byte
buffers and a specified buffer full ratio of 3Fh. The formula is:
INTEGER((ratio/256)*number of buffers). Thus INTEGER((3Fh/256)*10) = 2.
The target should attempt to reselect the initiator on read operations
whenever two or more buffers are full.
The bus inactivity limit field indicates the maximum time in 100 microsecond
increments that the target is permitted to assert the BSY signal without a
REQ/ACK handshake. If the bus inactivity limit is exceeded the target shall
attempt to disconnect if the initiator has granted the disconnect privilege
(see 5.6.7) and it is not restricted by DTDC. This value may be rounded as
defined in 6.5.4. A value of zero indicates that there is no bus inactivity
limit.
The disconnect time limit field indicates the minimum time in 100
microsecond increments that the target shall wait after releasing the SCSI bus
before attempting reselection. This value may be rounded as defined in 6.5.4.
A value of zero indicates that there is no disconnect time limit.
The connect time limit field indicates the maximum time in 100 microsecond
increments that the target is allowed to use the SCSI bus before disconnecting
if the initiator has granted the disconnect privilege (see 5.6.7) and it is
not restricted by DTDC. This value may be rounded as defined in 6.5.4. A
value of zero indicates that there is no connect time limit.
The maximum burst size field indicates the maximum amount of data that the
target shall transfer during a data phase before disconnecting if the
initiator has granted the disconnect privilege. This value is expressed in
increments of 512 bytes (e.g., a value of one means 512 bytes, two means 1024
bytes, etc.). A value of zero indicates there is no limit on the amount of
data transferred per connection.
The data transfer disconnect control (DTDC) field (Table 7-69) defines
further restrictions on when a disconnect is permitted.
Table 7-69: Data Transfer Disconnect Control
==============================================================================
DTDC Description
------ ----------------------------------------------------------------------
00b Data transfer disconnect control is not used. Disconnect is
controlled by the other fields in this page.
01b A target shall not attempt to disconnect once the data transfer of a
command has started until all data the command is to transfer has been
transferred. The connect time limit and bus inactivity limit are
ignored during the data transfer.
10b Reserved
11b A target shall not attempt to disconnect once the data transfer of a
command has started until the command is complete. The connect time
limit and bus inactivity limit are ignored once data transfer has
started.
==============================================================================
If DTDC is nonzero and the maximum burst size is nonzero the target shall
return CHECK CONDITION status. The sense key shall be set to ILLEGAL REQUEST
and the additional sense code set to ILLEGAL FIELD IN PARAMETER LIST.
7.3.3.3. Peripheral Device Page
Table 7-70: Peripheral Device Page
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | PS |Reserved| Page Code (09h) |
-----|-----------------------------------------------------------------------|
1 | Page Length (n-1) |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- Interface Identifier ---|
3 | (LSB) |
-----|-+---------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | Reserved |
-----|-+---------------------------------------------------------------------|
8 | |
-----|- - Vendor Specific - -|
n | |
==============================================================================
The peripheral device page (Table 7-70) is used to pass vendor-specific
information between an initiator and a peripheral interface below the target
(i.e., between the target and the peripheral device). This standard does not
define the format of this data, except to provide a standard header.
Interface identifier codes are defined in the Table 7-71.
Table 7-71: Interface Identifier Codes
==============================================================================
Reference
Code Value Interface Standard
----------- --------------------------------- --------------------------
0000h Small Computer System Interface X3.131
0001h Storage Module Interface X3.91M-1987
0002h Enhanced Small Device Interface X3.170
0003h IPI-2 X3.130-1986; X3T9.3/87-002
0004h IPI-3 X3.132-1987; X3.147-1988
0005h-7FFFh Reserved
8000h-FFFFh Vendor Specific
==============================================================================
7.3.4. Vital Product Data Parameters
This section describes the optional vital product data page structure and
the vital product data pages (Table 7-72) that are applicable to all SCSI
devices. These pages are optionally returned by the INQUIRY command (7.2.5)
and contain vendor-specific product information about a target or logical
unit. The vital product data may include vendor identification, product
identification, unit serial numbers, device operating definitions,
manufacturing data, field replaceable unit information, and other vendor-
specific information. This standard defines the structure of the vital
product data, but not the contents.
Table 7-72: Vital Product Data Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
82h ASCII Implemented Operating Definition Page 7.3.4.1
01h - 7Fh ASCII Information Page 7.3.4.2
81h Implemented Operating Definitions Page 7.3.4.3
00h Supported Vital Product Data Pages 7.3.4.4
80h Unit Serial Number Page 7.3.4.5
83h - BFh Reserved
C0h - FFh Vendor Specific
==============================================================================
7.3.4.1. ASCII Implemented Operating Definition Page
Table 7-73: ASCII Implemented Operating Definition
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Peripheral Qualifier | Peripheral Device Type |
-----|-----------------------------------------------------------------------|
1 | Page Code (82h) |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Page Length (n-3) |
-----|-----------------------------------------------------------------------|
4 | ASCII Operating Definition Description Length (m-4) |
-----|-----------------------------------------------------------------------|
5 | |
- - -|- - ASCII Operating Definition Description Data - -|
m | |
-----|-----------------------------------------------------------------------|
m+1 | |
- - -|- - Vendor-Specific Description Data - -|
n | |
==============================================================================
This page (Table 7-73) contains operating definition description data for
all operating definitions implemented by the target. The contents of this
data is not defined by this standard.
The peripheral qualifier field is defined in Table 7-16 and the peripheral
device type field is defined in Table 7-17.
The page length field specifies the length of the following page data. If
the allocation length is less than the length of the data to be returned the
page length shall not be adjusted to reflect the truncation.
The ASCII operating definition description length field specifies the length
in bytes of the ASCII operating definition description data that follows. If
the allocation length is less than the length of data to be returned, the
ASCII operating definition description length shall not be adjusted to reflect
the truncation. A value of zero in this field indicates that no ASCII
operating definition description data is available.
The ASCII operating definition description data field contains the ASCII
operating definition description data for the target or logical unit. The
data in this field shall be formatted in lines (or character strings). Each
line shall contain only graphic codes (i.e., code values 20h through 7Eh) and
shall be terminated with a NULL (00h) character.
7.3.4.2. ASCII Information Page
Table 7-74: ASCII Information Page
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Peripheral Qualifier | Peripheral Device Type |
-----|-----------------------------------------------------------------------|
1 | Page Code (01h - 7Fh) |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Page Length (n-3) |
-----|-----------------------------------------------------------------------|
4 | ASCII Length (m-4) |
-----|-----------------------------------------------------------------------|
5 | |
- - -|- - ASCII Information - -|
m | |
-----|-----------------------------------------------------------------------|
m+1 | |
- - -|- - Vendor-Specific Information - -|
n | |
==============================================================================
The ASCII information page (Table 7-74) returns information for the field
replaceable unit code returned in the REQUEST SENSE sense data (see 7.2.14).
The peripheral qualifier field is defined in Table 7-16 and the peripheral
device type field is defined in Table 7-17.
The page code field contains the same value as in the page code field of the
INQUIRY command descriptor block (see 7.2.5) and is associated with the field
replaceable unit code returned by the REQUEST SENSE command.
IMPLEMENTORS NOTE: The field replaceable unit field in the sense data
provides for 255 possible codes, while the page code field provides for only
127 possible codes. Thus it is not possible to return ASCII information
pages for the upper code values.
The page length field specifies the length of the following page data. If
the allocation length of the command descriptor block is too small to transfer
all of the page, the page length shall not be adjusted to reflect the
truncation.
The ASCII length field specifies the length in bytes of the ASCII
information that follows. If the allocation length is less than the length of
the data to be returned the ASCII length shall not be adjusted to reflect the
truncation. A value of zero in this field indicates that no ASCII information
is available for the specified page code.
The ASCII information field contains ASCII information concerning the field
replaceable unit identified by the page code. The data in this field shall be
formatted in one or more lines (or character strings). Each line shall
contain only graphic codes (i.e., code values 20h through 7Eh) and shall be
terminated with a NULL (00h) character.
The contents of the vendor-specific information field is not defined in this
standard.
7.3.4.3. Implemented Operating Definition Page
Table 7-75: Implemented Operating Definition Page
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Peripheral Qualifier | Peripheral Device Type |
-----|-----------------------------------------------------------------------|
1 | Page Code (81h) |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Page Length (n-3) |
-----|-----------------------------------------------------------------------|
4 |Reserved| Current Operating Definition |
-----|-----------------------------------------------------------------------|
5 | SavImp | Default Operating Definition |
-----|-----------------------------------------------------------------------|
6 | SavImp | |
-----|- - Supported Operating Definition List - -|
n | SavImp | |
==============================================================================
The implemented operating definition page (Table 7-75) defines the current
operating definition, the default operating definition, and which operating
definitions are implemented by the target. These operating definition values
are specified in the CHANGE DEFINITION command (see 7.2.1).
The peripheral qualifier field is defined in Table 7-16 and the peripheral
device type field is defined in Table 7-17.
The page length field specifies the length of the following operating
definitions. If the allocation length of the command descriptor block is too
small to transfer all of the page, the page length shall not be adjusted to
reflect the truncation.
For each operating definition there is an associated save implemented
(SavImp) bit. A SavImp bit of zero indicates that the corresponding operating
definition parameter cannot be saved. A SavImp bit of one indicates that the
corresponding operating definition parameter can be saved.
All returned operating definitions use the codes defined in Table 7-3. The
current operating definition field returns the value of the present operating
definition. The default operating definition field returns the value of the
operating definition the target uses when power is applied if no operating
definition is saved. The supported operating definition list returns one or
more operating definitions implemented by the target.
7.3.4.4. Supported Vital Product Data Pages
Table 7-76: Supported Vital Product Data Pages
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Peripheral Qualifier | Peripheral Device Type |
-----|-----------------------------------------------------------------------|
1 | Page Code (00h) |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Page Length (n-3) |
-----|-----------------------------------------------------------------------|
4 | |
-----|- - Supported Page List - -|
n | |
==============================================================================
The supported vital product data pages are shown in Table 7-76.
The peripheral qualifier field is defined in Table 7-16 and the peripheral
device type field is defined in Table 7-17.
The page code field shall be set to the value of the page code field in the
INQUIRY command descriptor block (see 7.2.5).
The page length field specifies the length of the supported page list. If
the allocation length is too small to transfer all of the page, the page
length shall not be adjusted to reflect the truncation.
The supported page list field shall contain a list of all vital product data
page codes implemented for the target or logical unit in ascending order
beginning with page code 00h.
7.3.4.5. Unit Serial Number Page
Table 7-77: Unit Serial Number Page
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Peripheral Qualifier | Peripheral Device Type |
-----|-----------------------------------------------------------------------|
1 | Page Code (80h) |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Page Length (n-3) |
-----|-----------------------------------------------------------------------|
8 | |
- - -|- - Product Serial Number - -|
n | |
==============================================================================
This page (Table 7-77) provides a product serial number for the target or
logical unit.
The peripheral qualifier field is defined in Table 7-16 and the peripheral
device type field is defined in Table 7-17.
The page length field specifies the length of the product serial number. If
the allocation length is too small to transfer all of the page, the page
length shall not be adjusted to reflect the truncation.
The product serial number field contains ASCII data that is vendor specific.
The least significant ASCII character of the serial number shall appear as the
last byte of a successful data transfer. If the product serial number is not
available, the target shall return ASCII spaces (20h) in this field.
(This page is intentionally blank.)
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