ISO 12142:2001
(Main)Electronic imaging — Media error monitoring and reporting techniques for verification of stored data on optical digital data disks
Electronic imaging — Media error monitoring and reporting techniques for verification of stored data on optical digital data disks
Imagerie électronique — Méthodes de surveillance et d'établissement de compte rendu d'erreurs pour la vérification des données stockées sur des disques optiques numériques
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 12142
First edition
2001-11-15
Electronic imaging — Media error
monitoring and reporting techniques for
verification of stored data on optical digital
data disks
Imagerie électronique — Méthodes de surveillance et d'établissement de
compte rendu d'erreurs pour la vérification des données stockées sur des
disques optiques numériques
Reference number
ISO 12142:2001(E)
©
ISO 2001
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ISO 12142:2001(E)
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ii © ISO 2001 – All rights reserved
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ISO 12142:2001(E)
Contents Page
Foreword.v
Introduction.vi
1 Scope .1
2 Normative references.1
3 Terms and definitions .1
4 Requirements.3
5 Conventions .4
6 Capabilities of media error monitoring techniques .4
7 High-level techniques.5
7.1 Introduction.5
7.2 Functional commands.6
7.2.1 Generic command description.6
7.2.2 Define Media Error Recovery Procedures (DMERP) .6
7.2.3 Read Defect Data List (RDDL) .7
7.2.4 Read Media Error Data (RDMED) .7
7.2.5 Read Log Data (RLD).8
7.2.6 Set Media Error Levels (SMEL) .9
7.2.7 Set Verify Media Error Levels (SVMEL).9
8 SCSI-2 level techniques .10
8.1 Introduction.10
8.2 The FORMAT UNIT command .11
8.2.1 Introduction.11
8.2.2 Requirements for media error monitoring and reporting.11
8.3 The LOG SELECT command .12
8.3.1 Introduction.12
8.3.2 Requirements for media error monitoring and reporting.12
8.4 The LOG SENSE command .13
8.4.1 Introduction.13
8.4.2 Requirements for media error monitoring and reporting.13
8.5 The MODE SELECT command .13
8.5.1 Introduction.13
8.5.2 Requirements for media error monitoring and reporting.13
8.6 The MODE SENSE command .14
8.6.1 Introduction.14
8.6.2 Requirements for media error monitoring and reporting.14
8.7 The READ DEFECT DATA command.14
8.7.1 Introduction.14
8.7.2 Requirements for media error monitoring and reporting.14
8.8 The READ LONG command.16
8.8.1 Introduction.16
8.8.2 Requirements for media error monitoring and reporting.16
8.9 The REQUEST SENSE command.17
8.9.1 Introduction.17
8.9.2 Requirements for media error monitoring and reporting.17
8.10 The VERIFY command .19
8.10.1 Introduction.19
8.10.2 Requirements for media error monitoring and reporting.19
8.11 The WRITE AND VERIFY command.19
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ISO 12142:2001(E)
8.11.1 Introduction.19
8.11.2 Requirements for media error monitoring and reporting.19
8.12 Parameters for optical disk devices .20
8.12.1 Media error monitoring and reporting associated parameters.20
8.12.2 Mode parameters .20
8.12.3 Log parameters.22
Annex A (informative) Recommendations on Verify Media Error Levels for early warning and Media
Error Levels for sector retirement.32
A.1 Introduction.32
A.2 Sector retirement guidelines according to ISO/IEC 10089 .32
A.3 Sector retirement guidelines according to ISO/IEC 13403 .32
Annex B (informative) Guidelines for use of media error monitoring and reporting techniques for the
verification of stored data on optical digital data disks .33
B.1 Introduction.33
B.2 Media error monitoring tools provided by this International Standard .34
B.2.1 Introduction.34
B.2.2 Interpreting media error reports.35
B.3 Deciding what to test.36
B.3.1 Introduction.36
B.3.2 Sampling methods.37
B.3.3 Estimation from sampling methods.38
B.3.4 Using baseline media error parameters .40
B.4 Analysing media error reports provided by optical disk subsystems or devices complying to
this International Standard, or similar media error reports .40
B.4.1 Introduction.40
B.4.2 Automating media testing.40
B.4.3 Media error testing and log maintenance .40
B.4.4 Sample graphs of media error reports specified in this International Standard .41
B.5 Using error distributions and statistical models to evaluate data integrity .56
B.5.1 Introduction.56
B.5.2 Error distributions and burst lengths.56
B.5.3 The uniform random error model.58
B.5.4 Gilbert models of burst length distributions .59
Annex C (informative) Modified Gilbert Model .61
Annex D (informative) Uniform, random error distributions.63
D.1 General description .63
D.2 Sector distribution of bytes in error .63
D.3 Maximum number of bytes in error per codeword per sector .63
D.4 Distribution of the number of bytes in error per codeword per sector.64
D.4.1 General.64
D.4.2 Maximum number of bytes in error per codeword per sector, first approach .64
D.4.3 Maximum number of bytes in error per codeword per sector, second approach .64
Bibliography .66
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ISO 12142:2001(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 12142 was prepared by Technical Committee ISO/TC 171, Document imaging
applications, Subcommittee SC 1, Quality.
Annexes A to D of this International Standard are for information only.
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ISO 12142:2001(E)
Introduction
Data and records managers in many organizations are already using optical disk-based information systems for
storing and retrieving large data sets and for storing valuable information. The optical disk drives that are part of
these systems are designed with powerful, but not unlimited, error correction capabilities. If the level of errors in an
optical digital data disk sector exceeds the error detection and correction mechanisms implemented in the optical
disk drive controller, the sector cannot be corrected (data loss might occur). System managers would like to be able
to use media error monitoring and reporting techniques to verify the information stored on optical digital data disks,
both initially when the data is transferred to that media and periodically to monitor the status of their data. The
Media Error Levels of correction taking place in the optical disk drive controller give an indication of the status of
data saved on these optical digital data disks.
This International Standard documents two approaches of media error monitoring and reporting techniques to verify
stored data on optical digital data disks:
a high-level approach with functional commands;
an implementation of a set of Small Computer System Interface-2 (SCSI-2) commands.
The high-level interface approach is independent of the host operating system (e.g. DOS, UNIX, OS/2, etc.) and
the interface that communicates between the optical disk device and the host (e.g. SCSI-2, IPI, LAN, etc.). In
addition, this high-level interface is media type and size independent. That is, it can be used with systems that use
Write-Once-Read-Many (WORM), rewritable, or partially read-only media; and with optical disk drives for different
media sizes from 90 mm to 356 mm media. Standard information about media errors allows end users and system
integrators to retrieve the same information even if their configurations consist of drives of different types, sizes,
and manufacturers. This information can be retrieved using the same software, which can be integrated into the
media error information utilities or device drivers.
The SCSI interface can be used instead of the high-level interface by using the selected set of SCSI-2 commands.
This selected set of SCSI-2 commands allows system manufacturers to develop drive type and size independent
data verification tools at the SCSI level through the use of media error monitoring and reporting techniques. The
use of a selected standard set of commands and approaches for media error monitoring and reporting allows any
implementor to use a common set of software tools that do not change from drive to drive.
The media error information that can be obtained using the high-level or SCSI-2 tools includes:
a list of reallocated sectors;
corrections above some Media Error Levels;
warning above some Verify Media Error Levels;
the total number of bytes in error, the number of bytes in error per sector, and the maximum number of bytes in
error in any sector codeword;
the uncorrected or corrected sector content;
errors encountered when reading header information, such as the sector address, sector marks, and
synchronization signals;
the maximum length of contiguous defective bytes.
By acquiring optical disk-based information systems that comply with this International Standard, system managers
will be able to access media error information at both a functional (higher) level and an interface level for optical
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ISO 12142:2001(E)
disk drives that implement ISO/IEC 9316. These tools facilitate a better understanding of the status of information
stored on optical digital data disks. The tools provide for design of more efficient media error monitoring and
reporting techniques, and data verification and recopying policies for transferring recorded data to similar or
different media in a timely and economic manner.
These media error monitoring and reporting techniques also allow system managers to obtain media error
information either in quasi-real time or during off-line operations. These techniques provide data recovery and
media error monitoring tools with different levels of sophistication. Information on media errors can be obtained,
which will enable the highlighting of trends on particular selected disks or in their entire data sets. Decisions on
frequency of use of these tools and the level of sophistication selected are not part of this International Standard.
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INTERNATIONAL STANDARD ISO 12142:2001(E)
Electronic imaging — Media error monitoring and reporting
techniques for verification of stored data on optical digital data
disks
1 Scope
This International Standard specifies two techniques for media error monitoring and reporting for the verification of
data stored on optical digital data disks:
high-level, which uses a set of functional commands;
SCSI-2 level, which uses a set of SCSI-2 commands.
It specifies two media error monitoring and reporting levels:
system level, which uses a set of functional commands that can be used by the operating system, application
software, and remote users;
optical disk device level, which uses a set of SCSI-2 commands that can be used by the device driver or a
device application programme.
Compliance to the requirements of this International Standard is specified in clause 4.
This International Standard applies to both rewritable and read only optical disk media.
Part of the information in this International Standard may be useful for CD-ROM subsystems, but implementations
for that technology are beyond the scope of this International Standard.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO/IEC 9316:1995, Information technology — Small Computer System Interface-2
ISO 12651:1999, Electronic imaging — Vocabulary
3 Terms and definitions
For the purposes of this International Standard, the terms and definitions given in ISO/IEC 9316, ISO 12651 and
the following apply.
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ISO 12142:2001(E)
3.1
band
specified number of contiguous tracks
NOTE It is a useful notation for referencing disk regions and plotting physically descriptive media error results.
3.2
byte error rate
BER
total number of bytes in error in a given sample divided by the sample size
3.3
constant angular velocity
recording method in which the number of clock periods per revolution is constant, independent of radius
NOTE This method implies that the amount of data per track is independent of radial position.
3.4
continuous–servo media
media on which the servo information for tracking is continuously available on adjacent grooves
3.5
data field
user data, defect management pointers (DMP), cyclic redundancy check (CRC), and error correction code (ECC)
bytes of a recorded sector
3.6
format
arrangement or layout of the data on the disk
3.7
initiator
SCSI device that requests an I/O process to be performed by another SCSI device (a target)
3.8
interleaving
process of allocating the physical sequence of units of data in order to render the data more immune to burst errors
3.9
native format
error correction code (ECC) data and control bytes, and stripping sync bytes
3.10
Reed−−Solomon codes
−−
error correction code particularly suited to the correction of errors that occur in bursts or are strongly correlated
3.11
sampled–servo media
media on which the servo information for focusing and tracking, along with clock information, is obtained by means
of periodic sampling of information on the optical disk
3.12
target
SCSI device that performs an operation requested by the initiator
3.13
verification of data
verification of the integrity and status of data
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ISO 12142:2001(E)
4 Requirements
This International Standard specifies the following two levels of compliance:
the BASIC level which uses a minimal set of functions and commands;
the EXTENDED level which uses all of the functions and commands in the BASIC level plus a MEDIA ERROR
LOG and user-set optical disk device programmable Media Error Levels and Verify Media Error Levels. The
EXTENDED level also allows users to interrogate the optical disk system (using the functional commands) or
the optical disk device (using a set of SCSI-2 commands) about the current setting of the optical disk device
set Media Error Levels and set Verify Media Error Levels.
Statements of compliance to the requirements of this International Standard shall state the level of compliance
used, BASIC or EXTENDED, at the system level interface and device level.
An optical disk-based information system is in accordance with this International Standard when it meets all the
requirements specified in clause 7 (for BASIC or EXTENDED compliance).
An optical disk device that conforms to ISO/IEC 9316 is in accordance with this International Standard when it
meets all the requirements specified in clause 8 (for BASIC or EXTENDED compliance).
Table 1 summarizes the BASIC and EXTENDED levels of compliance at the optical disk-based system level
(system level). Table 2 summarizes the BASIC and EXTENDED levels of compliance at the optical disk device
level (application of SCSI-2 commands for optical disk devices).
Table 1 — System level compliance
Functional level for optical disk-based subsystems: Level of compliance
Function description BASIC EXTENDED
Define media error recovery procedures (DMERP) Yes Yes
Read defect data list (RDDL) Yes Yes
Read media error data (RDMED) Yes Yes
Read log data (RLD) – Media error log and current Media Error No Yes
Levels
Set Media Error Levels (SMEL) No Yes
Set Verify Media Error Levels (SVMEL) No Yes
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ISO 12142:2001(E)
Table 2 — Conformance at the optical disk device level
Application of SCSI-2 commands for Level of compliance
optical disk devices BASIC EXTENDED
The FORMAT UNIT command Yes Yes
The LOG SELECT command and the following pages: No Yes
The media error log (MEL) page No Yes
The clear MEL page No Yes
The LOG SENSE command and the following pages: No Yes
The MEL page No Yes
The clear MEL page No Yes
The MODE SELECT command and the following pages: No Yes
The read-write error recovery page for optical disk devices
No Yes
The verify recovery page for optical disk devices No Yes
The MODE SENSE command and the following pages: No Yes
The read-write error recovery page for optical disk devices No Yes
The verify recovery page for optical disk devices No Yes
The READ DEFECT DATA command and the PDL, SDL, and WDL Yes Yes
The READ LONG command Yes Yes
The REQUEST SENSE command, the sense keys 01h or 03h, and Yes Yes
the related ASC or ASCQs
The VERIFY command Yes Yes
The WRITE AND VERIFY command Yes Yes
5 Conventions
This International Standard follows the conventions given in 4.2 of ISO/IEC 9316:1995. For the purpose of
identification, the parameters “Media Error Levels” and “Verify Media Error Levels” used in this International
Standard are shown with first upper case letters. The following conventions from ISO/IEC 9316 are reproduced:
Numbers that are not immediately followed by lower-case b or h are decimal values.
Numbers immediately followed by lower-case b (xxb) are binary values.
Numbers immediately followed by lower case h (xxh) are hexadecimal values.
6 Capabilities of media error monitoring techniques
The high-level interface functions specified in clause 7 and the application of SCSI-2 commands specified in
clause 8 pro
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