ISO 23868:2008

INTERNATIONAL ISO
STANDARD 23868
First edition
2008-10-15

Document management — Monitoring
and verification of information stored on
130 mm optical media
Gestion de documents — Surveillance et vérification de l'information
stockée sur des supports optiques de 130 mm




Reference number
ISO 23868:2008(E)
©
ISO 2008

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ISO 23868:2008(E)
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ISO 23868:2008(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 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 23868 was prepared by Technical Committee ISO/TC 171, Document management applications,
Subcommittee SC 1, Quality.
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ISO 23868:2008(E)
Introduction
Many organizations now use optical media for long-term storage of information. It is assumed that a disk
selected for recording has already been qualified for that purpose. It is therefore important to be able to verify
that data have been recorded correctly and remain readable for the required amount of time. Previous ISO
Standards clearly specified requirements for interchange, and methods for predicting the lifetime of optical
media but did not contain methods for validation of the quality of written data.
Longevity is limited both by media degradation and by technology obsolescence. Interchange needs to be
regularly verified to assure that information on existing recorded media will continue to be recoverable. Users
can have a maintenance policy that protects disks against unanticipated failure or use, such as by making one
archival copy, another to function as a backup or master, and another for routine access. Hardware support
lifecycles typically vary between 5 years to 10 years and technology lifecycles usually end after 20 years.
Consequently, recordings that require a longer lifecycle might have to be transferred to upgraded platforms
every 10 years to 20 years.
Optical media for long-term storage should be evaluated. Significant longevity differences can exist for disks
from different media manufacturers and also between disks from the same media manufacturer. Degradation
can be more rapid for disks of very poor initial quality than for high quality recordings. Disks with an initially
poor quality do not offer sufficient headroom to avoid reaching the unrecoverable error threshold before the
next scheduled inspection, which for archival disks is to be avoided. This means that a disk of high initial
recorded quality that maintains this condition for life is expected to have superior longevity.
Powerful cyclic redundancy check (CRC) error correction systems that are embedded in the disk and utilized
by the drive can mask degradation. In the absence of drive standards, functionality does not allow the user to
verify, in a simple manner, the quality of information recorded on a particular disk. Methods described in this
International Standard specify a quality control policy that can non-destructively identify degradation, and
thereby support timely and effective corrective action.

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INTERNATIONAL STANDARD ISO 23868:2008(E)

Document management — Monitoring and verification of
information stored on 130 mm optical media
1 Scope
This International Standard specifies test methods to determine the quality of data on recorded media and
provides specifications enabling end-user organizations to monitor data quality and ongoing conformance with
the error limits required for its class identified by the manufacturer of the drive/media. This International
Standard defines error rate monitoring capabilities and procedures associated with 130 mm optical media
while being used in a production environment to ensure that data are still readable throughout the expected
life of the media.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 12651, Electronic imaging — Vocabulary
ISO/IEC 17345, Information technology — Data interchange on 130 mm rewritable and write once read many
ultra density optical (UDO) disk cartridges — Capacity: 30 Gbytes per cartridge — First generation
ISO/IEC 11976, Data interchange on 130 mm rewritable and write-once-read-many ultra density optical (UDO)
disk cartridges — Capacity: 60 Gbytes per cartridge — Second generation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12651, ISO/IEC 17345,
ISO/IEC 11976, and the following apply.
3.1
end-of life
EOL
loss of interchange whereby information cannot be reliably retrieved
4 Test method
4.1 General
The method specified in this International Standard to determine the quality of data on recorded media is
based on a knowledge of the error correcting codes used to correct for inevitable media defects and the
deterioration during normal life of the media. At the time of writing, the data should be verified by the writing
system. During this verification process, the level of defects shall be checked and only data which require a
small percentage of the error correction capability shall be accepted by the writing system. This International
Standard defines a method for subsequent analysis of the remaining error correction capability when the
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ISO 23868:2008(E)
media are read on a reference drive. In addition, the performance of the servos on the media shall be checked
to determine if any unacceptable media distortion has occurred.
4.2 Calibration of test drive
The drive manufacturer provides reference disks, that have been checked on calibrated equipment. These
media shall be provided with a test report documenting the acceptable range of results that shall be obtained
when scanned on a drive to be used for archive data scanning. Any drive used to perform the media quality
tests shall pass the check with reference media.
4.3 Test parameters
The remaining error correction capability and servo performance of the media that are scanned shall be
measured using a media scan. In order to keep the scan to a manageable time, a percentage of the surface
shall be scanned.
During the scan of a disk, the following operations shall be performed.
a) The surface of the media shall be scanned to determine the location of written sectors.
b) A minimum of every tenth track of user written data shall be read and the number of errors in each code
word calculated so as to ensure that there is sufficient remaining correction capability in the written
sectors. The user may select to scan 100 % of the data depending on the value attributed to the content
of the media.
c) If > 75 % of the available error correction capability in any sector tested is required to recover valid data,
the media shall be reported as being at risk. In this case, the first measure shall be to clean the media
according to the manufacturer's instructions and to rescan for defects. If the same error is reported, the
data should be migrated within 2 years of the date of testing.
d) The servo channels shall be monitored to verify that none of the allowable thresholds are exceeded, for
example due to surface dust or scratches. The maximum servo disturbances are defined in the relevant
ISO specification for the media type (ISO/IEC 17345, ISO/IEC 11976). In this case, the first measure shall
be to clean the media according to the manufacturer's instructions and to rescan for defects. If the same
error is reported, the data should be migrated within two years of the date of testing.
e) The sector addresses shall be checked to ensure that at least one ID field in every sector is readable
without errors. If this condition is not met, the media shall be reported as being at risk. In this case, the
first measure shall be to clean the media according to the manufacturer's instructions and to rescan for
defects. If the same error is reported, the data should be migrated within two years of the date of testing.
f) The remaining spares area shall be checked to ensure that the relocation rate is acceptable. Less than
50 % of the spares allowed shall have been used. The spares allowed shall be allocated in proportion to
the percentage of the user area written. If this condition is not met, the media shall be reported as being
at risk. In this case, the first measure shall be to clean the media according to the manufacturer's
instructions and to rescan for defects. If the same error is reported, the data should be migrated within
two years of the date of testing.
4.4 Test set-up
Before testing a media cartridge, the drive to be used shall be calibrated using reference media supplied by
the drive manufacturer. The cartridge to be tested should be inspected for physical damage but no attempt
should be made to clean the media surface.
In general, media cleaning is detrimental to performance unless carried out using the correct materials to a
specification. Only in the event of a disk cartridge failing the scan, should the media be cleaned. See
informative Annex A for recommendations on disk cleaning. Disk cleaning should only be performed using the
recommended disk cleaner and cleaning fluid supplied by the media vendor.
On no account
...