ISO/IEC 10995:2008

INTERNATIONAL ISO/IEC
STANDARD 10995
First edition
2008-04-15

Information technology — Digitally
recorded media for information
interchange and storage — Test method
for the estimation of the archival lifetime
of optical media
Technologies de l'information — Supports enregistrés numériquement
pour l'échange et le stockage d'information — Méthode d'essai pour
l'estimation de la durée de vie d'archivage des supports optiques




Reference number
ISO/IEC 10995:2008(E)
©
ISO/IEC 2008

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ISO/IEC 10995:2008(E)
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ISO/IEC 10995:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Conformance. 1
3 Normative references . 2
4 Terms and definitions. 2
5 Conventions and notations . 4
5.1 Representation of numbers . 4
5.2 Names . 4
6 List of acronyms . 4
7 Measurements. 4
7.1 Summary. 4
7.1.1 Stress Incubation and Measuring . 4
7.1.2 Assumptions . 4
7.1.3 Error Rate . 5
7.1.4 Data Quality . 5
7.1.5 Regression . 5
7.2 Test specimen . 5
7.3 Recording conditions. 5
7.3.1 Recording test environment . 6
7.3.2 Recording method . 6
7.4 Playback conditions . 6
7.4.1 Playback tester. 6
7.4.2 Playback test environment . 6
7.4.3 Calibration . 6
7.5 Disk testing locations. 7
8 Accelerated stress test. 7
8.1 General. 7
8.2 Stress conditions. 7
8.2.1 General. 7
8.2.2 Temperature (T). 8
8.2.3 Relative humidity (RH). 8
8.2.4 Incubation and Ramp Profiles . 8
8.3 Measuring Time intervals. 9
8.4 Stress Conditions Design . 9
8.5 Media Orientation. 10
9 Data Evaluation . 10
9.1 Time-to-failure . 10
9.2 Eyring acceleration model (Eyring Method) . 10
9.3 Data analysis . 11
Annex A (normative) Data Analysis Steps Outline for Calculation of Media Life. 12
Annex B (normative) Analysis for Calculation of Media Life. 13
Annex C (normative) Uncontrolled Ambient Condition Media Life Calculation . 25
Annex D (informative) Truncated Test Method (Determination of Media Life Lower Bound) . 26
Annex E (informative) Bootstrap Method. 29
Annex F (informative) Relation between BER and PI Sum 8. 31
Bibliography . 32
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ISO/IEC 10995:2008(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national 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 and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 10995 was prepared by Ecma International (as ECMA-379) and was adopted, under a special “fast-
track procedure”, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with its
approval by national bodies of ISO and IEC.
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ISO/IEC 10995:2008(E)
Introduction
Markets and industry have developed the common understanding that the property referred to as the archival
life of data recorded to optical media plays an increasingly important role for the intended applications. The
existing standard test methodologies for recordable media include magneto-optical media and recordable
compact disk systems. It was agreed that the project represented by this International Standard be
undertaken in order to provide a methodology that includes the testing of newer, currently available products.
The Optical Storage Technology Association (OSTA) initiated work on this subject and developed the initial
drafts. Following that development, the project was moved to Ecma International TC 31 for further
development and finalization. OSTA and Ecma wish to thank the members and organizations in NIST, CDs21
Solutions, and DCAj for their support of the development of this International Standard.

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INTERNATIONAL STANDARD ISO/IEC 10995:2008(E)

Information technology — Digitally recorded media for
information interchange and storage — Test method for the
estimation of the archival lifetime of optical media
1 Scope
This International Standard specifies an accelerated aging test method for estimating the life expectancy for
the retrievability of information stored on recordable or rewritable optical disks.
This test includes details on the following formats: DVD-R/-RW/-RAM, +R/+RW. It may be applied to
additional optical disk formats with the appropriate specification substitutions and may be updated by
committee in the future as required.
This International Standard includes the following:
⎯ stress conditions;
⎯ assumptions;
⎯ ambient conditions:
⎯ controlled storage condition, e.g. 25 °C and 50 % RH, using the Eyring model,
⎯ uncontrolled storage condition, e.g. 30 °C and 80 % RH, using the Arrhenius model;
⎯ evaluation system description;
⎯ specimen preparation;
⎯ data acquisition procedure;
⎯ data interpretation.
The methodology includes only the effects of temperature (T) and relative humidity (RH). It does not attempt
to model degradation due to complex failure mechanism kinetics, nor does it test for exposure to light,
corrosive gases, contaminants, handling, and variations in playback subsystems. Disks exposed to these
additional sources of stress or higher levels of T and RH are expected to experience shorter usable lifetimes.
2 Conformance
Media tested by this methodology shall conform to all normative references specific to that media format.
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ISO/IEC 10995:2008(E)
3 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/IEC 16448:2002, Information technology — 120 mm DVD — Read-only disk
ISO/IEC 16449:2002, Information technology — 80 mm DVD — Read-only disk
ISO/IEC 17341:2006, Information technology — Data Interchange on 120 mm and 80 mm Optical Disk using
+RW Format – Capacity: 4,7 Gbytes and 1,46 Gbytes per Side (Recording speed up to 4X)
ISO/IEC 17342:2004, Information technology — 80 mm (1,46 Gbytes per side) and 120 mm (4,70 Gbytes per
side) DVD re-recordable disk (DVD-RW)
ISO/IEC 17344:2006, Information technology — Data Interchange on 120 mm and 80 mm Optical Disk using
+R Format – Capacity: 4,7 Gbytes and 1,46 Gbytes per Side (Recording speed up to 16X)
ISO/IEC 17592:2004, Information technology — 120 mm (4,7 Gbytes per side) and 80 mm (1,46 Gbytes per
side) DVD rewritable disk (DVD-RAM)
ISO/IEC 23912:2005, Information technology — 80 mm (1,46 Gbytes per side) and 120 mm (4,70 Gbytes per
side) DVD Recordable Disk (DVD-R)
ISO/IEC 25434:2007, Information technology — Data interchange on 120 mm and 80 mm optical disk using
+R DL format — Capacity: 8,55 Gbytes and 2,66 Gbytes per side (recording speed up to 8x)
ISO/IEC 26925:2006, Information technology — Digital storage media for information interchange — Data
Interchange on 120 mm and 80 mm Optical Disk using +RW HS Format — Capacity: 4,7 Gbytes and 1,46
Gbytes per Side (Recording speed 8X)
ISO/IEC 29642:2007, Information technology — Data Interchange on 120 mm and 80 mm optical disk using
+RW DL format – Capacity: 8,55 Gbytes and 2,66 Gbytes per side (recording speed 2,4x)
4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
4.1
archival
ability of a medium or system to maintain the retrievability of recorded information for a specified extended
period of years
4.2
Arrhenius method
accelerated aging model based on the effects of temperature
4.3
baseline
initial test analysis measurements (e.g. initial error rate) after recording and before exposure to a stress
condition; measurement at stress time t=0 hours
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ISO/IEC 10995:2008(E)
4.4
bootstrap method
statistical method for estimating the sampling distribution by re-sampling with replacement from the original
sample
NOTE See Annex E.
4.5
Eyring Method
accelerated aging model based on the effects of temperature and relative humidity
4.6
error rate
rate of errors on the sample disk measured before error correction is applied
4.7
incubation
process of enclosing and maintaining controlled test sample environments
4.8
life expectancy
LE
length of time estimation that information is predicted to be retrievable in a system while in a specified
environmental condition
4.9
maximum error rate
maximum of the error rate measured anywhere in one of the relevant areas on the disk
NOTE 1 For DVD-R/RW and +R/+RW this is the Maximum PI Sum 8.
NOTE 2 For DVD-RAM this is the Maximum BER.
4.10
retrievability
ability to recover physical information as recorded
4.11
stress
temperature and relative humidity variables to which the sample is exposed for the duration of test incubation
intervals
4.12
system
combination of hardware, software, storage medium and documentation used to record, retrieve and
reproduce information
4.13
uncorrectable error
error in the playback data that was not corrected by the error correcting decoders
NOTE For DVD-R/RW, +R/+RW, and DVD-RAM, this is an error that is uncorrected by the Reed-Solomon product
code defined in ISO/IEC 16448 for DVD ROM systems.
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ISO/IEC 10995:2008(E)
5 Conventions and notations
5.1 Representation of numbers
A measured value is rounded off to the least significant digit of the corresponding specified value. For instance,
it implies that a specified value of 1,26 with a positive tolerance of + 0,01 and a negative tolerance of - 0,02
allows a range of measured values from 1,235 to 1,275.
5.2 Names
The names of entities, e.g. specific tracks, fields, zones, etc. are given a capital initial.
6 List of acronyms
BER byte error rate
LCL lower confidence limit
LE life expectancy
PI parity (of the) inner (code)
7 Measurements
7.1 Summary
7.1.1 Stress Incubation and Measuring
A sampling of disks will be measured at 4 stress conditions plus a control disk at room ambient condition. A
minimum number of 20 disks will be included as a group for each stress condition as shown in Table 2.
Each stress condition’s total time will be divided into interval time periods. Each disk in each group of disks will
have their initial error rates measured before their exposure to stress conditions. Thereafter, each disk will be
measured for their error rates after each stress condition incubation time interval. The control disk will also be
measured following each incubation time interval.
7.1.2 Assumptions
This Standard makes the following assumptions for applicability of media to be tested:
⎯ specimen life distribution is appropriately modelled by a statistical distribution,
⎯ the Eyring model can be used to model acceleration with the two stresses involved (temperature and
relative humidity),
⎯ the dominant failure mechanism acting at the usage condition is the same as that at the accelerated
conditions,
⎯ the compatibility of the disk and drive combination will affect the disk’s initial recording quality and the
resulting archival test outcome,
⎯ a hardware and software system needed to read the disk will be available at the time the retrievability of
the information is attempted,
⎯ the recorded format will be recognizable and interpretable by reading software.
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ISO/IEC 10995:2008(E)
7.1.3 Error Rate
Of all specimen media the Error rate shall be measured in the disk testing locations as defined in 6.5. For
each sample the Maximum error rate shall be determined.
Each DVD-R/RW, +R/+RW disk will have their maximum PI Sum 8 (Max PI-8) determined.
Each DVD-RAM disk will have its maximum byte error rate (Max BER) determined.
Other disk formats not referenced in this document will have the maximum of their defined error rates
determined.
Data collected at each time interval for each individual disk are then used to determine the estimated lifetime
for that disk at that stress condition.
7.1.3.1 PI Sum 8
Per ISO/IEC 16448:2002, a row in an ECC block that has at least 1 byte in error constitutes a PI error. PI Sum
8 is measured over 8 ECC blocks. In any 8 consecutive ECC blocks the total number of PI errors, also called
PI Sum 8, before error correction shall not exceed 280.
7.1.3.2 BER
The number of erroneous symbols shall be measured at any consecutive 32 ECC blocks in the first pass of
the decoder before correction. The BER is the number of erroneous symbols divided by the total number of
symbols included in the 32 consecutive ECC blocks. The maximum value of the BER measured over the area
-3
specified in 6.5 shall not exceed 10 . (See Annex F).
7.1.4 Data Quality
Data quality is checked by plotting the median rank of the estimated time to failure values with a best fit line
for each stress condition. The lines are then checked for reasonable parallelism.
7.1.5 Regression
The time-to-failure values at each stress condition are then regressed to find a histogram of the time-to-failure
values at ambient condition using the bootstrap method.
The mean lifetimes are regressed against temperature and relative humidity according to an Eyring
acceleration model.
7.2 Test specimen
The disk sample set shall represent the construction, materials, manufacturing process, quality and variation
of the final process output.
Consideration shall be made to shelf life. Disks with longer shelf time before recording and testing may impact
test results. Shelf time shall be representative of normal usage shelf time.
7.3 Recording conditions
Before entering media into accelerated aging tests, they shall be recorded as optimally as is practicable,
according to the descriptions given in the related standard. OPC (optimum power control) during writing
process shall serve as the method to achieve recorded media minimum error rates. It is generally understood
that optimally recorded media will yield the longest predicted life results. Media is deemed acceptable for entry
into the aging tests when its error rate and all other media parametric specifications are found to be within its
respective standard’s specification limits.
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ISO/IEC 10995:2008(E)
Recording hardware is at the discretion of the recording party. It may be either commercial drive-based or
specialty recording tester based. It shall be capable of producing recordings that meet all specifications.
The maximum recording speed shall be at the media’s highest rated speed and this speed shall be reported.
7.3.1 Recording test environment
When performing the recordings, the air immediately surrounding the media shall have the following
properties:
temperature:  23 °C to 35 °C
relative humidity:  45 % to 55 %
atmospheric pressure: 60 kPa to 106 kPa
No condensation on the disk shall occur. Before testing the disk shall be conditioned in this environment for
48 h minimum. It is recommended that before testing the entrance surface is cleaned according to the
instructions of the manufacturer of the disk.
7.3.2 Recording method
Specimen disks shall be recorded at a single session and finalized.
7.4 Playback conditions
7.4.1 Playback tester
All media shall be read by the playback tester as specified in each of the medium’s standard and at their
specified test conditions.
Specimen media shall be read as described in the format standards identified in Clause 3.
7.4.2 Playback test environment
When measuring the error rates, the air immediately surrounding the disk shall have the following properties:
temperature:  23 °C to 35 °C
relative humidity:  45 % to 55 %
atmospheric pressure: 60 kPa to 106 kPa
Unless otherwise stated, all tests and measurements shall be made in this test environment.
7.4.3 Calibration
The test equipment shall be calibrated as prescribed by its manufacturer using calibration disks approved by
said manufacturer and as needed before disk testing.
A control disk shall be maintained at ambient conditions and its error rate measured at the same time the
stressed disks are measured initially and after each stress interval.
The mean and standard deviation of the control disk shall be established by collecting at least five
measurements. Should any individual error rate reading differ from the mean by more than three times the
standard deviation, the problem shall be corrected and all data collected since the last valid control point shall
be re-measured.
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ISO/IEC 10995:2008(E)
7.5 Disk testing locations
Testing locations shall be a minimum of three bands spaced evenly from inner, middle and outer radius
locations on the disk as indicated in Table 1. The total testing area shall represent a minimum of 5 % of the
disk. Each of the three test bands shall have more than 750(2EEh) ECC Blocks for 80 mm disks, and
2 400(960h) ECC Blocks for 120 mm disks.
Table 1 - Nominal radii of the three test bands
DVD-R/RW, +R/+RW disk
DVD-RAM disk

(Single Layer / Dual Layer)
80 mm 120 mm 80 mm 120 mm
Band 1 25,0 25,0 24,1-25,0 24,1-25,0
Band 2 30,0 40,0 29,8-30,8 39,4-40,4
Band 3 35,0 55,0 34,6-35,6 54,9-55,8
8 Accelerated stress test
8.1 General
Information properly recorded on an archival quality optical disk should have a life expectancy exceeding a
predetermined number of years. Accelerated aging studies are used in order to conclude that a life
expectancy exceeds the predetermined minimum number of years. This test plan is intended to provide the
information necessary to satisfactorily evaluate the particular optical disk system including proposed archival
quality optical disks.
8.2 Stress conditions
8.2.1 General
Stress conditions for this test method are increases in temperature and relative humidity. The stress
conditions are used to accelerate the chemical reaction rate from what would occur normally at ambient or
usage conditions. The chemical reaction is considered degradation in desired material property that eventually
leads to disk failure.
Four stress conditions and the minimum number of specimens for those stress conditions that shall be used
are shown in Table 2. Additional specimens and conditions may be used if desired for improved precision.
The total time for each stress condition as given in Table 2 is divided into four equal incubation durations. The
temperature and relative humidity during each incubation cycle shall be controlled as depicted in Table 3 and
Figure 1. After each cycle of incubation all specimens shall be measured.
Table 2 - Stress conditions for use with the Eyring Method
Test cell Test stress condition Number of Incubation Total time Intermediate Min equilibration
number (inc) specimens duration RH duration
Temp (°C) %RH hours hours %RH hours
1a 85 85 20 250 1 000 30 7
2a 85 70 20 250 1 000 30 6
3a 65 85 20 500 2 000 35 9
4a 70 75 30 625 2 500 33 11

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ISO/IEC 10995:2008(E)
8.2.2 Temperature (T)
The temperature levels chosen for this test plan are based on the following:
− there shall be no change of phase within the test system over the test-temperature range. This restricts
the temperature to greater than 0 °C and less than 100 °C,
− the temperature shall not be so high that plastic deformation occurs anywhere within the disk structure.
The typical substrate material for media is polycarbonate (glass transition temperature ~150 °C). The glass
transition temperature of other layers may be lower. Experience with high-temperature testing of DVDs and
+R/+RW disks indicates that an upper limit of 85 °C is practical for most applications.
8.2.3 Relative humidity (RH)
Experience indicates that 85 % RH is the generally accepted upper limit for control within most accelerated
test cells.
8.2.4 Incubation and Ramp Profiles
The relative humidity transition (ramp) profile is intended to avoid moisture condensation within the substrate,
minimize substantial moisture gradients in the substrate and to end at ramp down completion with the
substrate equilibrated to ambient condition. This is accomplished by varying the moisture content of the
chamber only at the stress incubation temperature, and allowing sufficient time for equilibration during ramp-
down based on the diffusion coefficient of water in polycarbonate.
Table 3 - T and RH transition (ramp) profile for each incubation cycle
Process step Temperature Relative humidity Duration
°C % hours
Start at T at RH —
amb amb
T, RH ramp to T to RH 1,5 ± 0,5
inc int
RH ramp at T to RH 1,5 ± 0,5
inc inc
Incubation at T at RH See Table 2
inc inc
RH ramp at T to RH 1,5 ± 0,5
inc int
Equilibration at T at RH See Table 2
inc int
T, RH ramp to T to RH 1,5 ± 0,5
amb amb
end at T at RH —
amb amb
amb = room ambient T or RH (T or RH )
amb amb
inc = stress incubation T or RH (T or RH )
inc inc
int = intermediate relative humidity (RH ) that at T supports the same equilibrium
int in
...