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15. Optical Memory Devices
15.1. Model for Optical Memory Devices
An optical memory device is a is one that can potentially support a variety
of optical media, (e.g., read-only, write-once, erasable, or reversible). In
several respects an optical memory device is similar to a direct-access
device. However optical memory devices typically offer features that are not
available with other devices, including very large capacity removable media.
These devices often require the functions which are not found in direct-
access devices such as logical block update, pre-erasure before writing, or
scanning for blank medium and twelve-byte command descriptor blocks.
This standard has specific device types for write-once and CD-ROM devices
which also use optical media, but are not capable of supporting a several
types of optical media. It is possible to implement devices using write-once
media as optical memory devices. It is possible to implement devices using
read-only media as optical memory devices, however devices using CD-ROM media
have certain unique characteristics and should not be implemented as optical
memory devices.
A model of optical memory devices is complicated by the nature of one of its
potential advantages, that it can support media which has different
characteristics. There are three types of optical media in general use, read-
only, write-once and reversible. Read-only media is typically used as for
publishing applications requiring dissemination of large amounts of data,
since the data can be replicated on a disk at low cost. Write-once media is
used in applications that have large backup or archiving requirements. It is
also used in applications that have a need for large amounts of on-line
reference information. Reversible media is typically used in applications
that need large amounts of temporary storage (e.g., graphics workstations) and
can take advantage of removable media. In some applications reversible media
drives are used in place of direct-access devices.
Reversible media usually needs to be reversed (erased, blanked) before new
data can be written. In such cases an erase operation is required before data
can be written. Some optical memory devices perform this erase operation
implicit with each write operation which typically will impact the data
throughput. Some devices can perform the erase as a separately. The ERASE
command may be used to erase areas of the medium with a corresponding
increase in data throughput on subsequent write operations. Products using
optical media should not be implemented as direct-access devices due to the
overhead penalty on performance from the emulation and lack of support in
direct-access devices to take advantage of the sophisticated features
available in with optical memory devices.
The type of medium supported by the device and the type of medium currently
loaded can be determined by examining the MODE SENSE data. One unique feature
of optical memory devices is support of media with mixed types (e.g., media
with read-only and write-once areas). The INQUIRY command informs the
initiator that the target is an optical memory device; the initiator should
then determine the medium type from the MODE SENSE data. The initiator needs
to be cognizant of medium type since the devices characteristics can change
when the media is changed.
Write-once media can have valid data written to a logical block once. This
is an important feature where audit trails and permanent archives are needed.
Many optical memory devices supporting write-once media have the ability to
update a logical block, preserving the previous generation of data. These
devices usually provide a means to recover the previous data through use of
commands that allow read access to the different generations of data that are
stored at the same logical block address.
An important requirement in dealing with optical media is determining the
which logical blocks are contain written data and which are blank. A blank
logical block is one that is properly initialized so that data written to it
can be recovered. The logical blocks usually have a flag associated with each
that indicates whether they have been written or not.
Many of the strategies used to manage write once and erasable media depend
on being able to determine the boundary between written and blank areas of the
medium. The MEDIUM SCAN command is useful in finding blank areas for
subsequent write operations.
15.1.1. Defect Management
Defect management can also be performed by use of logical block can be
updating in a manner similar to that used by direct-access devices with the
REASSIGN BLOCKS command. The advantage of using the updating (which is not
supported by direct-access devices) is access to the previous data.
The update operation assigns an alternate physical block to the logical
block while simultaneously writing the data to the block. Commands are
provided to allow the recovery of previous generations of updated blocks.
Defect management on optical-memory devices is usually vendor specific.
However there are standards for some types of optical-memory media that
specify defect management techniques. These standards, where they exist, may
supersede the implementation requirements pertaining to error and defect
reporting in this standard.
15.1.2. Error Reporting
If any of the following conditions occur during the execution of a command
the target shall return CHECK CONDITION status. The appropriate sense key and
additional sense code should be set. The following table illustrates some
error conditions and the applicable sense keys. The table does not provide an
exhaustive enumeration of all conditions that may cause the CHECK CONDITION
status.
Condition Sense Key
---------------------------------------------- ----------------------------
Invalid logical block address ILLEGAL REQUEST
Unsupported option requested ILLEGAL REQUEST
Target reset or medium change since
last command from this initiator UNIT ATTENTION
Self diagnostic failed HARDWARE ERROR
Unrecovered read error MEDIUM ERROR
HARDWARE ERROR
Recovered read error RECOVERED ERROR
Overrun or other error that might
be resolved by repeating the command ABORTED COMMAND
Attempt to write on write protected medium DATA PROTECT
Attempt to read a blank or previously
unwritten block. BLANK CHECK
Attempt to write a previously written
block and blank checking is enabled. BLANK CHECK
Attempt to write on read-only medium. DATA PROTECT
In the case of an invalid logical block address, the sense data information
field shall be set to the logical block address of the first invalid address.
In the case of an attempt to read a blank or previously unwritten block, the
sense data information field shall be set to the logical block address of the
first blank block encountered. The data read up to that block shall be
transferred.
In the case of an attempt to write a previously written block and blank
checking is enabled, the sense information field shall be set to the logical
block address of the first non-blank block encountered.
15.2. Commands for Optical Memory Devices
The commands for optical memory devices shall be as shown in Table 15-1 and
15-2.
Table 15-1: Commands for Optical Memory Devices(1)
==============================================================================
Operation
Command Name Code Type Section Page
------------------------------------------------------------------------------
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
ERASE(10) 2Ch O 15.2.1
ERASE(12) ACh O 15.2.2
FORMAT UNIT 04h O 8.2.1
INQUIRY 12h M 7.2.5
LOCK UNLOCK CACHE 36h O 8.2.2
LOG SELECT 4Ch O 7.2.6
LOG SENSE 4Dh O 7.2.7
MEDIUM SCAN 38h O 15.2.3
MODE SELECT(6) 15h O 7.2.8
MODE SELECT(10) 55h O 7.2.9
MODE SENSE(6) 1Ah O 7.2.10
MODE SENSE(10) 5Ah O 7.2.11
PRE-FETCH 34h O 8.2.3
PREVENT ALLOW MEDIUM REMOVAL 1Eh O 8.2.4
READ(6) 08h O 8.2.5
READ(10) 28h M 8.2.6
READ(12) A8h O 15.2.4
READ BUFFER 3Ch O 7.2.12
READ CAPACITY 25h M 8.2.7
READ DEFECT DATA(10) 37h O 8.2.8
READ DEFECT DATA(12) B7h O 15.2.5
READ GENERATION 29h O 15.2.6
READ LONG 3Eh O 8.2.9
READ UPDATED BLOCK 2Dh O 15.2.7
REASSIGN BLOCKS 07h O 8.2.10
RECEIVE DIAGNOSTIC RESULTS 1Ch O 7.2.13
RELEASE 17h M 8.2.11
REQUEST SENSE 03h M 7.2.14
RESERVE 16h M 8.2.12
REZERO UNIT 01h O 8.2.13
=============================================================================
Table 15-2: Commands for Optical Memory Devices(2)
==============================================================================
Operation
Command Name Code Type Section Page
------------------------------------------------------------------------------
SEARCH DATA EQUAL(10) 31h O 8.2.14.1
SEARCH DATA EQUAL(12) B1h O 15.2.8
SEARCH DATA HIGH(10) 30h O 8.2.14.2
SEARCH DATA HIGH(12) B0h O 15.2.8
SEARCH DATA LOW(10) 32h O 8.2.14.3
SEARCH DATA LOW(12) B2h O 15.2.8
SEEK(6) 0Bh O 8.2.15
SEEK(10) 2Bh O 8.2.15
SEND DIAGNOSTIC 1Dh M 7.2.15
SET LIMITS(10) 33h O 8.2.16
SET LIMITS(12) B3h O 15.2.9
START STOP UNIT 1Bh O 8.2.17
SYNCHRONIZE CACHE 35h O 8.2.18
TEST UNIT READY 00h M 7.2.16
UPDATE BLOCK 3Dh O 15.2.10
VERIFY(10) 2Fh O 15.2.11
VERIFY(12) AFh O 15.2.12
WRITE(6) 0Ah O 8.2.20
WRITE(10) 2Ah M 15.2.13
WRITE(12) AAh O 15.2.14
WRITE AND VERIFY(10) 2Eh O 15.2.15
WRITE AND VERIFY(12) AEh O 15.2.16
WRITE BUFFER 3Bh O 7.2.17
WRITE LONG 3Fh O 8.2.23
=============================================================================
Key: M = Command implementation is mandatory.
O = Command implementation is optional.
The following codes are vendor specific: 20h, 21h, 22h, 23h, and C0h through
FFh. All remaining codes for optical memory devices are reserved for future
standardization.
15.2.1. ERASE(10) Command
Table 15-3: ERASE(10) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (2Ch) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | ERA |Reserved| RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | (MSB) |
-----|--- Transfer Length ---|
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The ERASE(10) command (Table 15-3) requests that the target erase the
specified number of blocks starting at the specified logical block address on
the medium. As used here, "erased" means either the medium shall be erased,
or a pattern shall be written on the medium that appears to the target as no
data present. The blocks erased shall be considered blank for purposes of
blank checking (see 15.1). The previous data recorded on the medium, if any,
shall not be recoverable.
The erase all (ERA) bit set to one indicates that all remaining blocks on
the medium shall be erased. If the ERA bit is set to one and if the number of
blocks is not zero, the target shall return CHECK CONDITION, and the sense key
shall be set to ILLEGAL REQUEST, with an additional sense code of INVALID
FIELD IN CDB.
See 8.2.2 for a description of the RelAdr bit and logical block address
field.
The transfer length specifies the number of contiguous logical blocks that
shall be erased when the ERA bit is zero. If the ERA bit is zero a transfer
length of zero indicates that no blocks shall be erased. This condition shall
not be considered as an error and no data shall be erased. Any other value
indicates the number of logical blocks that shall be erased.
This command shall be terminated with a status of RESERVATION CONFLICT if
any reservation access conflict (see 8.2.12) exists and no data shall be
erased.
IMPLEMENTORS NOTE: This command allows the user to separate the erase and
write operations. This may increase system performance in certain
applications.
15.2.2. ERASE(12) Command
Table 15-4: ERASE(12) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (ACh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | ERA |Reserved| RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- ---|
7 | |
-----|--- Transfer Length ---|
8 | |
-----|--- ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Control |
==============================================================================
The ERASE(12) command (Table 15-4) requests that the target erase the
specified number of blocks starting at the specified logical block address on
the medium.
See the ERASE(10) command (15.2.1) for a description of the fields in this
command.
15.2.3. MEDIUM SCAN Command
Table 15-5: MEDIUM SCAN Command
==============================================================================
Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (38h) |
------|----------------------------------------------------------------------|
1 | Logical Unit Number | WBS | ASA | RSD | PRA | RelAdr |
------|----------------------------------------------------------------------|
2 | (MSB) |
------|--- ---|
3 | |
------|--- Logical Block Address ---|
4 | |
------|--- ---|
5 | (LSB) |
------|----------------------------------------------------------------------|
6 | Reserved |
------|----------------------------------------------------------------------|
7 | Reserved |
------|----------------------------------------------------------------------|
8 | Parameter List Length |
------|----------------------------------------------------------------------|
9 | Control |
==============================================================================
The MEDIUM SCAN command (Table 15-5) requests the target to scan the medium
for a contiguous set of written or blank logical blocks.
A written block search (WBS) bit of zero indicates that the scan is for
blank blocks. A WBS bit of one indicates that the scan is for written blocks.
An advanced scan algorithm (ASA) bit of zero indicates that the scan area is
scanned in sequential order (as selected by the RSD bit). An ASA bit of one
indicates to the target that the written and blank areas within the scan area
form contiguous extents (as opposed to scattered blocks). This indication is
advisory to the target.
IMPLEMENTORS NOTE: The purpose of this bit is to allow the target to use a
more advanced algorithm (such as a binary search) to locate the requested
blocks.
A reverse scan direction (RSD) bit of zero indicates the scan shall begin
with the first logical block of the scan area. A RSD bit of one indicates the
scan shall begin with the last logical block of the scan area.
A partial results acceptable (PRA) bit of zero indicates that the scan shall
not be considered satisfied until a contiguous set of blocks is found within
the scan area which is greater than or equal in size to the number of blocks
requested, and meets the other criteria specified in the command descriptor
block. A PRA bit of one indicates that the scan may be satisfied by a
contiguous set of blocks within the scan area which is less than the number of
blocks requested, and meets the other criteria specified in the command
descriptor block. In this case, the target shall determine the largest
contiguous set of blocks in the scan area for reporting to the initiator.
See 8.2.2 for a description of the RelAdr bit and logical block address
field.
The parameter list length specifies the length in bytes of the parameter
list that shall be transferred during the DATA OUT phase. A parameter list
length of zero indicates that the number of blocks requested field has a value
of one, and the number of blocks to scan field has a value of zero. This
condition shall not be considered an error. The contents of the parameter
list are specified in Table 15-6.
A link bit of zero indicates a non-linked command and if the scan is
satisfied, the command shall be terminated with a CONDITION MET status. A
REQUEST SENSE command can then be issued to determine the starting logical
block address of the area that meets the request. If the scan is not
satisfied and no error occurs, the command shall be terminated with GOOD
status.
A link bit of one indicates a command is linked to the MEDIUM SCAN command
and if the search is satisfied, CONDITION MET status is returned and the next
command is executed. If the RelAdr bit in the next command is one, the
logical block address of the next command is used as a displacement from the
logical block address at which the search was satisfied. If a linked scan
is not satisfied, the command is terminated with a CHECK CONDITION status. A
REQUEST SENSE command may then be issued.
A REQUEST SENSE command following a satisfied MEDIUM SCAN command shall:
(1) Return a sense key of EQUAL if the scan was satisfied by a contiguous
set of blocks equal in size to the number of blocks requested. If the scan was
satisfied by a contiguous set of blocks not equal in size to the number of
blocks requested, then a sense key of NO SENSE shall be returned.
(2) Return the valid bit set to one.
(3) Return the logical block address of the first logical block of the
contiguous set of blocks that satisfied the scan criteria in the information
bytes.
(4) Return the number of contiguous logical blocks meeting the scan criteria
in the command specific information bytes.
A REQUEST SENSE command following an unsatisfied MEDIUM SCAN command shall:
(1) Return a sense key of NO SENSE if no errors occurred during the command
execution.
(2) Return the valid bit set to zero.
Table 15-6: MEDIUM SCAN Parameter List
==============================================================================
Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | (MSB) |
------|--- ---|
1 | |
------|--- Number of Blocks Requested ---|
2 | |
------|--- ---|
3 | (LSB) |
------|----------------------------------------------------------------------|
4 | (MSB) |
------|--- ---|
5 | |
------|--- Number of Blocks to Scan ---|
6 | |
------|--- ---|
7 | (LSB) |
==============================================================================
The number of blocks requested field specifies the number of blocks that
meet the specified requirements. The number of blocks requested field, if set
to zero, indicates that the scan shall not take place. This shall not be
considered an error condition.
The number of blocks to scan field specifies the length in blocks of the
area to be scanned on the medium. The number of blocks to scan field, if set
to zero, indicates that the scan shall continue for all remaining blocks on
the medium or until the scan is satisfied. See 15.1.3 for a description of
error handling.
15.2.4. READ(12) Command
Table 15-7: READ(12) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (A8h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | DPO | FUA | Reserved | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- ---|
7 | |
-----|--- Transfer Length ---|
8 | |
-----|--- ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Control |
==============================================================================
The READ(12) command (Table 15-7) requests that the target transfer data to
the initiator from the medium. See the READ(10) command (8.2.6) for a
complete description of the fields in this command.
15.2.5. READ DEFECT DATA(12) Command
Table 15-8: READ DEFECT DATA(12) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (B7h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Plist | GList | Defect List Format |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | Reserved |
-----|-----------------------------------------------------------------------|
5 | Reserved |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- ---|
7 | |
-----|--- Allocation Length ---|
8 | |
-----|--- ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Control |
==============================================================================
The READ DEFECT DATA(12) command (Table 15-8) requests that the target
transfer the medium defect data to the initiator. See the READ DEFECT DATA(10)
command (8.2.8) for a description of the fields in this command.
The READ DEFECT DATA(12) list header (Table 15-9) contains an eight byte
header, followed by zero or more defect descriptors.
Table 15-9: READ DEFECT DATA(12) LIST HEADER
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Reserved |
-----|-----------------------------------------------------------------------|
1 | Reserved | PList | GList | Defect List Format |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
-----|-----------------------------------------------------------------------|
4 | (MSB) |
-----|--- ---|
5 | |
-----|--- Defect List Length |
6 | |
-----|--- ---|
7 | (LSB) |
==============================================================================
Defect Descriptors
==============================================================================
0-n | |
==============================================================================
See the description of the READ DEFECT DATA defect list (Table 8-19) for a
description of the fields in this header.
15.2.6. READ GENERATION Command
Table 15-10: READ GENERATION Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (29h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | Reserved |
-----|-----------------------------------------------------------------------|
8 | Allocation Length |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The READ GENERATION command (Table 15-10) requests that the target transfer
to the initiator the maximum generation address for the logical block
specified.
See 8.2.2 for a description of the RelAdr bit and logical block address
field.
The READ GENERATION data is defined in Table 15-11.
Table 15-11: Maximum Generation Data Block
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | (MSB) |
-----|--- Maximum Generation Address ---|
1 | (LSB) |
-----|-----------------------------------------------------------------------|
2 | Reserved |
-----|-----------------------------------------------------------------------|
3 | Reserved |
==============================================================================
The maximum generation address field defines the maximum generation address
available for the logical block address specified.
15.2.7. READ UPDATED BLOCK(10) Command
Table 15-12: READ UPDATED BLOCK(10) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (2Dh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | DPO | FUA | Reserved | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | Latest | (MSB) |
-----|------------ Generation Address |
7 | (LSB) |
-----|-----------------------------------------------------------------------|
8 | Reserved |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The READ UPDATED BLOCK(10) command (Table 15-12) requests that the target
transfer data to the initiator from the specified generation and logical
block.
See 8.2.6 for a description of the cache control bits (DPO and FUA). See
8.2.2 for a description of the RelAdr bit and logical block address field.
One block of data is transferred during the DATA IN phase.
The latest bit determines the meaning of the generation address field. A
latest bit of zero indicates that the generation address is specified relative
to the first generation of the block; generation address zero specifies the
first generation. Increasing generation addresses specify later generations.
A latest bit of one indicates that the generation address is specified
relative to the latest generation of the block; generation address zero
specifies the most recent generation. Increasing generation addresses specify
earlier generations.
If the requested generation does not exist, the command shall be terminated
with CHECK CONDITION status. The sense key shall be set to BLANK CHECK, and
the additional sense code shall be set to GENERATION DOES NOT EXIST.
This command shall be terminated with a status of RESERVATION CONFLICT if
any reservation access conflict (see 8.2.12) exists and no data shall be
transferred.
15.2.8. SEARCH DATA(12) Commands
Table 15-13: SEARCH DATA(12) Commands
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (B0h, B1h, B2h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Invert | Reserved | SpnDat | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- ---|
7 | |
-----|--- Transfer Length ---|
8 | |
-----|--- ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Control |
==============================================================================
The SEARCH DATA(12) commands (Table 15-13) search one or more logical blocks
for equality or inequality to a data pattern. See the SEARCH DATA(10)
commands (8.2.14) for a description of the fields in this command.
15.2.9. SET LIMITS(12) Command
Table 15-14: SET LIMITS(12) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (B3h) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | RdInh | WrInh |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- ---|
7 | |
-----|--- Number of Blocks ---|
8 | |
-----|--- ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Control |
==============================================================================
The SET LIMITS(12) command (Table 15-14) defines the range within which
subsequent linked commands may operate. See the SET LIMITS(10) command
(8.2.16) for a description of the fields in this command.
15.2.10. UPDATE BLOCK Command
Table 15-15: UPDATE BLOCK Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (3Dh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | Reserved | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | Reserved |
-----|-----------------------------------------------------------------------|
8 | Reserved |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The UPDATE BLOCK command (Table 15-15) requests that the target logically
replace data on the medium with the data sent during the DATA OUT phase.
See 8.2.2 for a description of the RelAdr bit and logical block address
field.
One block of data is transferred during the DATA OUT phase.
IMPLEMENTORS NOTE: See the MODE Parameters (15.3) for a description of the
behavior of the UPDATE BLOCK command relative to the enable blank check
(EBC) bit.
This standard does not define the result of a WRITE command issued to a
block previously updated by an UPDATE BLOCK command when blank checking is
disabled.
IMPLEMENTORS NOTE: It is recommended that the target inhibit this behavior.
A logical block may be updated until the alternate block area is exhausted.
The alternate blocks used for the update operation shall not be reported in
the READ CAPACITY data. If the alternate block area is exhausted the command
shall be terminated with CHECK CONDITION and the sense key shall be set to
MEDIUM ERROR, and the additional sense code set to NO DEFECT SPARE LOCATION
AVAILABLE.
If the report updated block read parameter specifies posting of recovered
errors for a read operation of a logical block that has had a successful
update operation performed occurs the command shall terminate with a CHECK
CONDITION status. The sense key shall be set to RECOVERED ERROR and the
additional sense code set to UPDATED BLOCK READ.
15.2.11. VERIFY(10) Command
Table 15-16: VERIFY Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (2Fh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | DPO |Reserved| BlkVfy | BytChk | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | (MSB) |
-----|--- Verification Length |
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The VERIFY command (Table 15-16) requests that the target verify the data on
the medium.
If the MODE SELECT command is implemented, and the Verify Error Recovery
Parameters page is also implemented, then the current settings in that page
define the verification criteria. If the Verify Error Recovery Parameters page
is not implemented, then the verification criteria is vendor unique.
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 the data written on the medium and the data transferred from the
initiator. The data shall be transferred as it would be for a WRITE command.
If the compare is unsuccessful, for any reason, the target shall return CHECK
CONDITION status and the sense key shall be set to MISCOMPARE.
A blank verify (BlkVfy) bit of one causes a verification that the blocks are
blank.
If the BytChk is one when the BlkVfy bit is one, this shall be considered an
error. The target shall return CHECK CONDITION status and the sense key shall
be set to ILLEGAL REQUEST, and the additional sense code set to INVALID FIELD
IN CDB.
See 8.2.6 for a description of the cache control bits (DPO). See 8.2.2 for
a description of the RelAdr bit and logical block address field.
The verification length specifies the number of contiguous logical blocks of
data or blanks that shall be verified. A verification length of zero
indicates that no logical blocks shall be verified. This condition shall not
be considered as an error. Any other value indicates the number of logical
blocks that shall be verified.
15.2.12. VERIFY(12) Command
Table 15-17: VERIFY(12) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (AFh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | DPO |Reserved| BlkVfy | BytChk | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- ---|
7 | |
-----|--- Verification Length ---|
8 | |
-----|--- ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Control |
==============================================================================
The VERIFY(12) command (Table 15-17) requests that the target verify the
data on the medium. See the VERIFY(10) command (15.2.11) for a description of
the fields in this command.
15.2.13. WRITE(10) Command
Table 15-18: WRITE(10) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (2Ah) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | DPO | FUA | EBP |Reserved| RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | (MSB) |
-----|--- Transfer Length |
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The WRITE(10) command (Table 15-18) requests that the target write the data
transferred from the initiator to the medium.
An erase by-pass (EBP) bit of zero indicates that the device will default to
the normal write operation. An EBP bit of one indicates that the target is
allowed to by-pass the erase operation prior to writing the data. When
accessing write-once media, the EBP bit shall be considered reserved.
See 8.2.6 for a description of the cache control bits (DPO and FUA). See
8.2.2 for a description of the RelAdr bit and logical block address field.
The transfer length specifies the number of contiguous logical blocks of
data that shall be transferred. A transfer length of zero indicates that no
data shall be transferred. This condition shall not be considered as an error
and no data shall be written. Any other value indicates the number of logical
blocks that shall be transferred.
This command shall be terminated with a status of RESERVATION CONFLICT if
any reservation access conflict (see 8.2.12) exists and no data shall be
written.
15.2.14. WRITE(12) Command
Table 15-19: WRITE(12) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (AAh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | DPO | FUA | EBP |Reserved| RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- ---|
7 | |
-----|--- Transfer Length ---|
8 | |
-----|--- ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Control |
==============================================================================
The WRITE(12) command (Table 15-19) requests that the target write the data
transferred from the initiator to the medium. See the WRITE(10) command
(15.2.13) for a description of the fields in this command.
15.2.15. WRITE AND VERIFY(10) Command
Table 15-20: WRITE AND VERIFY(10) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (2Eh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | DPO |Reserved| EBP | BytChk | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | Reserved |
-----|-----------------------------------------------------------------------|
7 | (MSB) |
-----|--- Transfer Length |
8 | (LSB) |
-----|-----------------------------------------------------------------------|
9 | Control |
==============================================================================
The WRITE AND VERIFY(10) command (Table 15-20) requests that the target
write the data transferred from the initiator to the medium and then verify
that the data is correctly written.
If the MODE SELECT command is implemented, and the Verify Error Recovery
Parameters page is also implemented, then the current settings in that page
define the verification criteria. If the Verify Error Recovery Parameters page
is not implemented, then the verification criteria is vendor unique.
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 the data written on the medium and the data transferred from the
initiator. The data shall be transferred as it would be for a WRITE command.
If the compare is unsuccessful, for any reason, the target shall return CHECK
CONDITION status and the sense key shall be set to MISCOMPARE.
An erase by-pass (EBP) bit of zero indicates that the device will default to
the normal write operation. An EBP bit of one indicates that the target is
allowed to by-pass the erase operation prior to writing the data. When
accessing write-once media, the EBP bit shall be considered reserved.
See 8.2.6 for a description of the cache control bits (DPO). See 8.2.2 for
a description of the RelAdr bit and logical block address field.
The transfer length specifies the number of contiguous logical blocks of
data that shall be transferred. A transfer length of zero indicates that no
logical blocks shall be transferred. This condition shall not be considered
as an error and no data shall be written. Any other value indicates the
number of logical blocks that shall be transferred.
15.2.16. WRITE AND VERIFY(12) Command
Table 15-21: WRITE AND VERIFY(12) Command
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | Operation Code (AEh) |
-----|-----------------------------------------------------------------------|
1 | Logical Unit Number | DPO |Reserved| EBP | BytChk | RelAdr |
-----|-----------------------------------------------------------------------|
2 | (MSB) |
-----|--- ---|
3 | |
-----|--- Logical Block Address ---|
4 | |
-----|--- ---|
5 | (LSB) |
-----|-----------------------------------------------------------------------|
6 | (MSB) |
-----|--- ---|
7 | |
-----|--- Transfer Length ---|
8 | |
-----|--- ---|
9 | (LSB) |
-----|-----------------------------------------------------------------------|
10 | Reserved |
-----|-----------------------------------------------------------------------|
11 | Control |
==============================================================================
The WRITE AND VERIFY(12) command (Table 15-21) requests that the target
write the data transferred from the initiator to the medium and then verify
that the data is correctly written. See the WRITE AND VERIFY(10) command
(15.2.15) for a description of the bits in this command.
15.3. Parameters for Optical Memory Devices
15.3.1. Diagnostic Parameters
This section defines the descriptors and pages for diagnostic parameters
used with optical memory devices.
The diagnostic page codes for optical memory devices are defined in Table
15-22.
Table 15-22: Diagnostic Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
00h List of Supported Parameters Page 7.3.1.1
01h - 3Fh Reserved (for all device type pages)
40h Translate Address Page 8.3.1
41h - 7Fh Reserved
80h - FFh Vendor specific pages
==============================================================================
15.3.2. Log Parameters
This section defines the descriptors and pages for log parameters used with
optical memory devices.
The log page codes for optical memory devices are defined in Table 15-23.
Table 15-23: 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
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
00h List of Supported Parameters Page 7.3.2.5
06h Non-Media Error Page 7.3.2.4
04h Reserved
08h - 2Fh Reserved
30h - 3Eh Vendor Specific
3Fh Reserved
==============================================================================
15.3.3. Mode Parameters
This section defines the descriptors and pages for mode parameters used with
optical memory devices.
The mode parameter list, including the mode parameter header and mode block
descriptor are defined in 7.3.3.
The medium-type code field is contained in the mode parameter header (see
Table 7-61 and 7-62). Table 15-24 defines the medium-type code values used
for optical memory devices.
Table 15-24: Optical Memory Medium-Type Codes
==============================================================================
Code Value Medium Type
---------- ------------------------------------------------------------------
00h Default (only one medium type supported)
01h Optical Read Only medium
02h Optical Write Once medium
03h Optical Reversible or Erasable medium
04h Combination of Read only and Write Once medium
05h Combination of Read only and Reversible or Erasable medium
06h Combination of Write Once and Reversible or Erasable medium
07h - 7Fh RESERVED
80h - FFh Vendor unique
==============================================================================
The device specific parameter field is contained in the mode parameter
header (see Table 7-61 and 7-62). Table 15-25 defines the device specific
parameter values used for optical memory devices.
Table 15-25: Optical Memory Device Specific Parameter
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
==============================================================================
| WP | Reserved | Cache | Reserved | EBC |
==============================================================================
The WP bit is reserved for the MODE SELECT command.
For the MODE SENSE command, a write protected (WP) bit of zero indicates
that the medium is write enabled. A WP bit of one indicates that the medium
is write protected. For read-only media the WP bit is reserved.
The cache bit is reserved for the MODE SELECT command.
For the MODE SENSE command, a cache bit of zero indicates that the target
does not contain a cache memory. A cache bit of one indicates that the target
contains a cache memory and supports the cache control bits (see 8.2.6).
For the MODE SELECT command, an enable blank check (EBC) bit of zero advises
the target to disable the blank checking operation of the medium during write
operations or during an UPDATE BLOCK command. An EBC bit of one enables blank
checking. If a non-blank block is found during a write operation, the command
shall be terminated with a CHECK CONDITION status and the sense key shall be
set to BLANK CHECK. If a blank block is found during an UPDATE BLOCK command,
the command shall be terminated with a CHECK CONDITION status and the sense
key shall be set to BLANK CHECK. For read-only media the EBC bit is reserved.
For the MODE SENSE command, an enable blank check (EBC) bit of zero
indicates that blank checking of the medium during write operations is
disabled. An EBC bit of one indicates that blank checking during write and
update operations is enabled. For read-only media the EBC bit is reserved.
The density code field is contained in the mode parameter block descriptor
(see Table 7-63). Table 15-26 defines the density code values used for
optical memory devices.
Table 15-26: Optical Memory Density Codes
==============================================================================
Density Optical Media
Code
------- ---------------------------------------------------------------------
00h Default density (currently mounted density)
Diameter Sector Reference
mm (inch) Type Size Tracks Sides Servo Standard Note
---------- ---- -------- ------ ----- ----- ---------- ----
01h 86 (3.5) R/W 512/1024 12500 1 660-D 1
02h 89 (3.5) R/W 512/1024 12500 2 581-D 1
03h 130 (5.25) R/W 512/1024 18750 2 CS 607-I 1
04h 130 (5.25) W-O 512/1024 30000 2 SS 655-D 1,2
05h 130 (5.25) W-O 512/1024 20000 2 SS 659-D 1,3
06h 130 (5.25) W-O 512/1024 18750 2 CS 457-D 1
07h 200 (8.0) 407-D 1,4
08h 300 (12.0) 1024 2 408-D 1,4
09h 356 (14.0) 1024 56350 2 456-D 1
80h - FFh Vendor unique
All others Reserved
==============================================================================
Key:
Type Servo
----------------------------- ------------------------------
R/W Erasable CS Continuous Servo
W-O Write Once SS Sampled Servo
R/O Read Only
NOTES:
(1) The reference standard refers to an ANSI X3B11 project under
development. The project may have several documents describing different
aspects of the media. Please contact the Secretariat for current information
on status and availability.
(2) RZ modulation.
(3) 4/15 modulation.
(4) This project is not presently active.
The mode page codes for optical memory devices are shown in Table 15-27.
Table 15-27: Mode Page Codes
==============================================================================
Page Code Description Section
------------------------------------------------------------------------------
08h Caching Page 8.3.3.1
0Ah Control Mode Page 7.5.3.1
02h Disconnect-Reconnect Page 7.3.3.2
0Bh Medium Types Supported Page 8.3.3.4
06h Optical Memory Page 15.3.3.1
09h Peripheral Device Page 7.3.3.3
01h Read-Write Error Recovery Page 8.3.3.6
07h Verify Error Recovery Page 8.3.3.8
03h - 05h Reserved
0Ch - 1Fh Reserved
3Fh Returns all pages (valid only for the MODE SENSE command)
00h Vendor specific (does not require page format)
20h - 3Eh Vendor specific
==============================================================================
15.3.3.1. Optical Memory Page
Table 15-28: Optical Memory Page
==============================================================================
Bit| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Byte | | | | | | | | |
==============================================================================
0 | PS |Reserved| Page Code (06h) |
-----|-----------------------------------------------------------------------|
1 | Parameter Length (02h) |
-----|-----------------------------------------------------------------------|
2 | Reserved | RUBR |
-----|-----------------------------------------------------------------------|
3 | Reserved |
==============================================================================
The optical memory page (Table 15-28) defines parameters for control of
optical memory devices.
The parameters savable (PS) bit is only used with the MODE SENSE command.
This bit is reserved with the MODE SELECT command. A PS bit of one indicates
that the target is capable of saving the page in a non-volatile vendor-
specific location.
A report updated block read (RUBR) bit of zero indicates the target shall
not report an error when a command performs a successful read of a block that
has been updated. A RUBR bit of one indicates the target shall terminate a
command that performs a read of a block that has been updated with CHECK
CONDITION status, the sense key set to RECOVERED ERROR, the additional sense
code set to UPDATED BLOCK READ, and the data shall be transferred to the
initiator. The default state of the RUBR bit for write-once devices (as
reported in the INQUIRY command) shall be one.
15.4. Glossary for Optical Memory Devices
blank. The logical block contains no information detectable by the target, or
is written with a pattern that appears to the target as no data present. The
logical block is considered ready for a write operation.
generation. Indicates a relative revision level of a logical block that has
been updated via the UPDATE BLOCK command. A logical block that has never
been updated has only one generation associated with it.
read-only medium. This is medium that may not be written by the initiator.
The media contains data prepared in a manner not defined by this standard.
update. To write new data to a logical block without destroying the previous
data. After a block has been updated, a normal read returns the most recent
generation of the data. Earlier generations are still available after the
update.
write-once medium. This is medium that may be written only once by the
initiator. Logical blocks on write-once media that have not been written are
considered blank. Logical blocks on write-once media that have been written
may not be written again.
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.