ISO/IEC 16963:2011

INTERNATIONAL ISO/IEC
STANDARD 16963
First edition
2011-10-01
Information technology — Digitally
recorded media for information
interchange and storage — Test method
for the estimation of lifetime of optical
media for long-term data storage
Technologies de l'information — Supports pour l'échange d'informations
et le stockage enregistrés numériquement — Méthode d'essai pour
l'estimation de la durée de vie de supports optiques pour le stockage à
long terme
Reference number
©
ISO/IEC 2011
©  ISO/IEC 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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Published in Switzerland
ii © ISO/IEC 2011 – All rights reserved

Contents Page
Foreword . v
Introduction . vi
1  Scope . 1
2  Conformance . 2
3  Normative references . 2
4  Terms and definitions . 3
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 . 5
7.1.3  Data Error . 5
7.1.4  Data Quality . 6
7.1.5  Regression . 6
7.2  Test specimen . 6
7.3  Recording conditions . 6
7.3.1  Recording test environment . 6
7.3.2  Recording method . 6
7.4  Playback conditions . 7
7.4.1  Playback tester . 7
7.4.2  Playback test environment . 7
7.4.3  Calibration . 7
7.5  Disk testing locations . 7
7.5.1  Rigorous stress condition testing . 7
7.5.2  Basic stress condition testing . 7
8  Accelerated stress test . 8
8.1  General . 8
8.2  Stress conditions . 8
8.2.1  General . 8
8.2.2  Temperature (T) . 9
8.2.3  Relative humidity (RH) . 9
8.2.4  Incubation and Ramp Profiles . 9
8.3  Measuring Time intervals . 10
8.4  Stress Conditions Design . 10
8.5  Media Orientation . 11
9  Lifetime Estimation . 11
9.1  Time to failure . 11
9.2  Accelerated Aging Test Methods . 11
9.2.1  Eyring acceleration model (Eyring Method) . 11
9.2.2  Arrhenius accelerated model (Arrhenius Method) . 12
9.3  Data Analysis . 12
9.4  Result of Estimated Media Life . 12
Annex A (normative) Outline of Media Life Estimation Method and Data Analysis Steps . 13
© ISO/IEC 2011 – All rights reserved iii

Annex B (normative) Media Life Estimation for the Controlled Storage Condition (Eyring method) .16
Annex C (normative) Media Life Estimation for the Harsh Storage Condition (Arrhenius method) .25
Annex D (informative) Interval Estimation for B Life using Maximum Likelihood .30
Bibliography .32

iv © ISO/IEC 2011 – All rights reserved

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 16963 was prepared by Ecma International (as ECMA-396) 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.

© ISO/IEC 2011 – All rights reserved v

Introduction
Markets and industry have developed a common understanding that the property referred to as the lifetime of
data recorded to optical media plays an increasingly important role for the intended applications. Disparate
standardized test methodologies exist for Magneto Optical media and recordable compact disk and DVD
systems. It was agreed that the project represented by this International Standard be undertaken in order to
provide a common methodology, applicable for various purposes, that includes the testing of currently
available writable CD and DVD optical media.
ISO/IEC JTC 1/SC 23/JWG 1, which is a Joint working group among ISO/TC 42, ISO/TC 171 and ISO/IEC
JTC 1/SC 23, initiated work on this subject and developed the initial drafts with assistance from Ecma
International TC31.
vi © ISO/IEC 2011 – All rights reserved

INTERNATIONAL STANDARD ISO/IEC 16963:2011(E)

Information technology — Digitally recorded media for
information interchange and storage — Test method for the
estimation of lifetime of optical media for long-term data

storage
1 Scope
This International Standard specifies an accelerated aging test method for estimating the lifetime of 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 and CD-R/RW. It may be
applied to additional optical disk formats, with substitution of the appropriate specifications, and may also be
updated by committee in the future as required.
This International Standard includes:
 stress conditions
 Basic stress condition and Rigorous stress condition testing for use with the Eyring Method and
testing for use with the Arrhenius Method.
 ambient storage conditions in which the lifetime of data stored on optical media is estimated
 Controlled storage condition, e.g. 25 °C and 50 % RH, representing well-controlled storage
conditions with full-time air conditioning. Eyring Method is used to estimate the lifetime under this
storage condition.
 Harsh storage condition, e.g. 30 °C and 80 % RH, representing the most severe conditions in which
users handle and store the optical media. Arrhenius Method is used to estimate the lifetime under
this storage condition.
 evaluation system description
 specimen preparation and data-acquisition procedure
 definition of and method for estimating lifetime of stored data on specified media
 data analysis for lifetime of stored data
 reporting format for estimated lifetime of stored data
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, or variations in playback subsystems. Disks exposed to these
additional sources of stress or higher levels of temperature and relative humidity are expected to experience
shorter usable lifetimes.
© ISO/IEC 2011 – All rights reserved 1

2 Conformance
Media tested by this methodology shall conform to all normative references specific to that media format.
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 10149:1995, Information technology — Data interchange on read-only 120 mm optical data disks
(CD-ROM) (ECMA-130)
ISO/IEC 12862:2009, Information technology — 120 mm (8,54 Gbytes per side) and 80 mm (2,66 Gbytes per
side) DVD recordable disk for dual layer (DVD-R for DL) (ECMA-382)
ISO/IEC 13170:2009, Information technology — 120 mm (8,54 Gbytes per side) and 80 mm (2,66 Gbytes per
side) DVD re-recordable disk for dual layer (DVD-RW for DL) (ECMA-384)
ISO/IEC 16448:2002, Information technology — 120 mm DVD — Read-only disk (ECMA-267)
ISO/IEC 16449:2002, Information technology — 80 mm DVD — Read-only disk (ECMA-268)
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) (ECMA-330)
ISO/IEC 17341:2009, 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) (ECMA-337)
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) (ECMA-338)
ISO/IEC 17344:2009, 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) (ECMA-349)
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) (ECMA-359)
ISO/IEC 25434:2008, 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 16X) (ECMA-364)
ISO/IEC 26925:2009, Information technology — 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) (ECMA-371)
ISO/IEC 29642:2009, 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) (ECMA-374)
ECMA-394, Recordable Compact Disc Systems CD-R Multi-Speed
ECMA-395, Recordable Compact Disc Systems CD-RW Ultra-Speed
2 © ISO/IEC 2011 – All rights reserved

4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
4.1
Arrhenius method
accelerated aging model based on the effects of temperature only
4.2
baseline
initial test analysis measurements (e.g., initial data errors) after recording and before exposure to a stress
condition, i.e. measurement at stress time t=0 hours
4.3
basic stress conditions
accelerated aging conditions for estimating the lifetime of data stored on optical media in a reasonable amount
of time and labour
4.4
B Life
5 percentile of the lifetime distribution (i.e. 5 % failure time) or 95 % survival lifetime
4.5
(B Life)
5 L
95 % lower confidence bound of B Life
4.6
B Life
50 percentile of the lifetime distribution (i.e. 50 % failure time) or 50 % survival lifetime
4.7
controlled storage condition
well-controlled storage conditions with full-time air conditioning (25 °C and 50 % RH) in which the lifetime of
data stored on optical media may be extended
4.8
Eyring method
accelerated aging model based on the effects of temperature and relative humidity
4.9
data error
data error on the sample disk measured before error correction is applied
4.10
harsh storage condition
most severe conditions in which users handle and store the optical media (30 °C and 80 % RH) in which the
lifetime of data stored on optical media may be shortened
4.11
incubation
process of enclosing and maintaining controlled test-sample environments
4.12
maximum data error
maximum data error measured anywhere in one of the relevant areas on the disk:
- for DVD-R/RW and +R/+RW, this is the Maximum PI Sum 8,
- for DVD-RAM, this is the Maximum BER, and
- for CD-R/RW, this is the Maximum C1 Ave 10.
© ISO/IEC 2011 – All rights reserved 3

4.13
retrievability
ability to recover physically-recorded information as recorded
4.14
rigorous stress conditions
accelerated aging conditions for estimating the lifetime of data stored on optical media with higher confidence
4.15
stress
temperature and relative humidity variables to which the sample is exposed for the duration of test incubation
intervals
4.16
system
combination of hardware, software, storage medium and documentation used to record, retrieve and
reproduce information
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 follows 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 capitalized.
6 List of acronyms
BER byte error rate
BLER block error rate
PI parity (of the) inner (code)
Section 2 — Test and Evaluation
7 Measurements
7.1 Summary
7.1.1 Stress Incubation and Measuring
A sampling of disks will be measured at four stress conditions for the Basic stress condition testing or five
stress conditions for the Rigorous stress condition testing for use with the Eyring Method, or three stress
condition for the Basic stress condition testing or four stress conditions for the Rigorous stress condition
testing for use with the Arrhenius Method.
4 © ISO/IEC 2011 – All rights reserved

Each stress condition’s total time will be divided into sub-interval time periods. Each disk in each group of
disks will have its initial data errors measured before their exposure to stress conditions. Thereafter, each disk
will be measured for its data errors after each stress condition incubation sub-interval time period.
The control disk for monitoring of tester can also be measured following each incubation time interval.
7.1.2 Assumptions
This International Standard makes the following assumptions for applicability of media to be tested
specimen life distribution is appropriately modelled by a statistical distribution,
the Eyring Method can be used to model acceleration with the both 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 retrieval of the
information is attempted,
the recorded format will be recognizable and interpretable by the reading software.
7.1.3 Data Error
Of all specimen media, the data errors shall be measured in the disk testing locations as defined in 7.5. For
each sample the Maximum Data Error shall be determined.
Each DVD-R/RW, +R/+RW disk will have its Maximum PI Sum 8 (Max PI Sum 8) determined.
Each DVD-RAM disk will have its Maximum Byte Error rate (Max BER) determined.
Each CD-R/RW disk will have its Maximum C1 Ave 10 (Max C1 Ave 10) determined.
Data collected at each time interval for each individual disk are then used to determine the predicted time to
failure 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 in 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 7.5 shall not exceed 10 .
7.1.3.3 C1 Ave 10
-2
IEC 60908:1999 specifies that the BLER averaged over any 10 seconds shall be less than 3×10 . At the
standard (1X) data transfer rate, the total number of blocks per second entering the C1-decoder is 7 350.
© ISO/IEC 2011 – All rights reserved 5

Thus, the number of C1 errors per second before error correction which is averaged over any 10 seconds,
called C1 Ave 10, shall not exceed 220.
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 log predicted time to failure values shall be calculated using linear regression.
Multiple linear regression is used for the Eyring Method and linear regression is used for the Arrhenius Method.
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.
7.3 Recording conditions
Before media are entered 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 the writing
process shall serve as the method to achieve minimum data errors. It is generally assumed that optimally-
recorded media will yield the longest predicted lifetime. Media is deemed acceptable for entry into the aging
tests when their data errors and all other media parametric specifications are found to be within their
respective standard’s specification limits.
The choice of recording hardware is at the discretion of the recording party. It may be either commercial drive-
based or speciality recording tester based. It shall be capable of producing recordings that meet all
specifications.
The recording speed used for testing shall be reported.
NOTE It is expected that lifetime of data on a disk may be affected by recording conditions including recording speed.
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 hrs minimum. It is recommended that, before testing, the entrance surface be cleaned according to the
instructions of the manufacturer of the disk.
7.3.2 Recording method
Specimen disks shall be recorded in a single session and finalized.
6 © ISO/IEC 2011 – All rights reserved

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 data errors, 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 should be calibrated as prescribed by its manufacturer using calibration disks approved by
said manufacturer and as needed before disk testing. A control disk should be maintained at ambient
conditions and its data error should be measured at the same time the stressed disks are measured, both
initially and after each stress sub interval.
The mean and standard deviation of the control disk shall be established by collecting at least five
measurements. Should any individual data error 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.
7.5 Disk testing locations
7.5.1 Rigorous stress condition testing
All data areas on a disk shall be tested.
7.5.2 Basic stress condition testing
Testing locations shall be a minimum of three bands spaced evenly from the 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 capacity. For DVDs and +R / +RW disks, each of the three test bands shall have more than 750 ECC
blocks for 80 mm disks, and 2 400 ECC blocks for 120 mm disks. For CDs, each of the three test bands shall
have more than 5900 sectors.
Table 1 — Nominal radii of the three test bands   (Unit; mm)
DVD- R / RW, +R / +RW disk
DVD- RAM disk CD-R/RW disk
(Single Layer / Dual Layer)
80 mm 120 mm 80 mm 120 mm 120 mm
Band 1 25,0 25,0 24,1-25,0 24,1-25,0 25,0
Band 2 30,0 40,0 29,8-30,8 39,4-40,4 40,0
Band 3 35,0 55,0 34,6-35,6 54,9-55,8 55,0
© ISO/IEC 2011 – All rights reserved 7

8 Accelerated stress test
8.1 General
Accelerated stress testing is used in order to estimate the lifetime of the optical disk. All information needed
for this testing is provided in this document.
8.2 Stress conditions
8.2.1 General
Stress conditions for this test method are increases in temperature and relative humidity (RH). The stress
conditions are intended to accelerate the chemical reaction rate from what would occur normally at ambient
storage or usage conditions. The chemical reaction is considered to be degradation in some desired material
property that eventually leads to disk failure.
Regarding use of the Eyring Method, five stress conditions for the Rigorous stress condition testing, and the
minimum number of specimens for those stress conditions that shall be used, are shown in Table 2. Four
stress conditions for the Basic stress condition testing, and the minimum numbers of specimens are also
shown in Table 3. Additional specimens and conditions may be used, if desired for improved precision.
Regarding use of the Arrhenius Method, stress conditions are given in Table C.1 and Table C.2 in Annex C.
The total time for each stress condition as given in Table 2 and Table 3 is divided into five and four equal
incubation sub-intervals respectively. The temperature and relative humidity (RH) during each incubation sub-
interval shall be controlled as given in Table 4 and shown in Figure 1. All specimens shall be measured after
each sub-interval of incubation.
Table 2 — Rigorous stress conditions for use with the Eyring Method
Maximum Minimum
Test stress Minimum
Number of incubation total Intermediate

condition equilibration
specimens sub-interval incubation RH
Test cell (incubation) duration time
time time
number
Temp (°C) % RH hours hours % RH hours
A 85 80 20 300 1 500 30 7
B 85 70 20 400 2 000 30 6
C 85 60 20 600 3 000 30 5
D 75 80 20 600 3 000 32 8
E 65 80 30 800 4 000 35 9
Table 3 — Basic stress conditions for use with the Eyring Method
Maximum Minimum
Test stress Minimum
Number of incubation total Intermediate
condition equilibration
specimens subinterval incubation RH
Test cell
(incubation) duration time
time time
number
Temp (°C) % RH hours hours % RH hours
A 85 80 20 250 1 000 30 7
B 85 70 20 250 1 000 30 6
C 65 80 20 500 2 000 35 9
D 70 75 30 625 2 500 33 11
NOTE Incubation duration should be decided according to media characteristic.
8 © ISO/IEC 2011 – All rights reserved

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 used 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,
+R/+RW disks and CD disks indicates that an upper limit of 85 °C is practical for most applications.
8.2.3 Relative humidity (RH)
Experience indicates that 80 % 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 on the substrate,
minimize substantial moisture gradients in the substrate and to end at ramp-down completion with the
substrate equilibrated to the 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 the
ramp down based on the diffusion coefficient of water in polycarbonate.
Table 4 — T and RH transition (ramp) profile for each incubation sub-interval
Temperature Relative humidity Duration
Process step
°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
int inc
equilibrium moisture absorption in polycarbonate as that supported at T
amb
and RH
amb
© ISO/IEC 2011 – All rights reserved 9

Relative Humidity (%) (RH)
Process step
T,RH RH Incubation RH Equilibration T,RH
Ramp Ramp Ramp Ramp
Temp.
RH
End
Start
Time (Hour)
Figure 1 — Graph of typical transition (ramp) profile
8.3 Measuring Time intervals
For data collection, PI Sum 8 (DVD-R, DVD-RW, +R, +RW), BER (DVD-RAM), or C1 Ave 10 (CD-R, CD-RW),
measurements for each disk will occur: 1) before disk exposure to any stress condition to determine its
baseline measurement and 2) after each sub-interval of incubation. The length of time for intervals is
dependent on the severity of the stress condition.
Using each disk's regression equation, the failure time for each disk shall then be computed for the stress
condition it was exposed to.
8.4 Stress Conditions Design
Table 2 for the Rigorous stress conditions and Table 3 for the Basic stress conditions specify the
temperatures, relative humidities, Maximum Incubation sub-intervals, minimum total incubation time, and
minimum number of specimens for each stress condition. A separate group of specimens shall be used for
each stress condition.
All temperatures shall be maintained within  2°C of the target temperature; all relative humidities shall be
maintained within  3 % RH of the target relative humidity.
The intermediate relative humidity in Table 2 and Table 3 are calculated assuming 25 °C and 50 % RH
ambient conditions. If the ambient is different, the intermediate relative humidity to be used is calculated using
the equation:
0,24 0,0037T
amb
RH   RH
int amb
0,24 0,0037T
inc
where:
T and T are the ambient and incubation temperature in units of °C;
amb inc
RH is the ambient relative humidity;
amb
RH is the intermediate relative humidity.
int
10 © ISO/IEC 2011 – All rights reserved

Temperature (℃）
The stress conditions tabulated in Table 2, Table 3 and Table 4 offer sufficient combinations of temperature
and relative humidity to satisfy the mathematical requirements of the Eyring Method to demonstrate linearity of
either Max PI Sum 8, Max BER, or Max C1 Ave 10, or their logs respectively, versus time, and to produce a
satisfactory confidence level to make a meaningful conclusion.
8.5 Media Orientation
Media subjected to this test method shall be maintained during incubation in a vertical position with a
minimum of 2 mm separation between disks to allow air flow between disks and to minimize deposition of
debris on disk surfaces, which could negatively influence the data error measurements.
9 Lifetime Estimation
9.1 Time to failure
All disks subjected to stress conditions shall have their time to failure calculated at the stress condition they
have been subjected to. Failure criteria values are: Max PI Sum 8 exceeding 280 for DVD-R/RW, +R/+RW,
-3
Max BER exceeding 10 for DVD-RAM and Max C1 Ave 10 exceeding 220 for CD-R/-RW.
Material degradation manifests itself as data errors in the disk, providing a relationship between disk errors
and material degradation. The chemical changes are generally expected to cause test data to have a
distribution that follows an exponential function over time. Therefore, test values of: PI Sum 8, BER or C1 Ave
10 as functions of time are expected to exhibit an exponential distribution.
The best function fitting an error trend can be found by regression of the test data against time, for example,
with a least squares fit. The time to failure per disk type can be calculated using the error trend function and
the failure criteria.
9.2 Accelerated Aging Test Methods
9.2.1 Eyring acceleration model (Eyring Method)
Using the Eyring model, the following equation is derived from the laws of thermodynamics and can be used
to handle the two critical stresses of temperature and relative humidity.
a H / kT (BC /T )RH
t AT e e
where
t is the time to failure;
A is the pre-exponential time constant;
a
T is the pre-exponential temperature factor;
∆H is the activation energy per molecule;
-23
k is the Boltzmann's constant (1,3807 × 10 J/molecule degree K);
T is the temperature (in Kelvin);
B, C are the RH exponential constants;
RH is the relative humidity;
For the temperature range used in this test method, “ a ” and “C” shall be set to zero. The Eyring model
equation then reduces to the following equation.
H / kT BRH
t Ae e
H
or, ln(t) ln(A)  B RH
kT
© ISO/IEC 2011 – All rights reserved 11

9.2.2 Arrhenius accelerated model (Arrhenius Method)
The Arrhenius Method uses only temperature stress for accelerated aging.
The time to failure is assumed to be governed by the following Arrhenius model equation.
H / kT
t Ae
H
ln(t) ln(A)
kT
9.3 Data Analysis
Data analysis is contained in the following Annexes:
Annex A: Outline of Media Life Estimation Method and Data Analysis Steps
Annex B: Media Life Estimation for the Controlled Storage Condition (Eyring Method)
Annex C: Media Life Estimation for the Harsh Storage Condition (Arrhenius Method)
Annex D: Interval Estimation for B5 Life using Maximum Likelihood
9.4 Result of Estimated Media Life
Estimated lifetime based on the data analysis shall be reported as follows.
(1) Number and title of this standard
(2) Ambient storage condition for lifetime estimation
25 °C / 50 % RH (Controlled storage condition) or 30 °C / 80 % RH (Harsh storage condition)
(3) Stress and testing condition
Rigorous stress condition testing or Basic stress condition testing
(4) The recording speed used for testing shall be reported. (see 7.3)
(5) B Life, B Life and 95 % lower confidence bound of B Life (= (B Life) )
50 5 5 5 L
ˆ
NOTE In case a more precise analysis is required or a large estimate is found, the 95 % lower confidence
bound of B Life should be computed according to Annex D.
12 © ISO/IEC 2011 – All rights reserved

Annex A
(normative)
Outline of Media Life Estimation Method and Data Analysis Steps
A.1 Data analysis for media life estimation
A.1.1 Assumptions for data analysis
Data analysis for lifetime estimation is based on the following assumptions.
- The lifetime of data recorded on an optical disk has a lognormal distribution.
- The Eyring Method is used for the Controlled storage condition (25 °C, 50 % RH). (see Annex B)
- The Arrhenius method is used for the Harsh storage condition (30 °C, 80 % RH). (see Annex C)
ˆ ˆ
ln B ln B
A.1.2 Lognormal model and point estimation of and
5 50
As lifetime t is distributed with lognormal distribution LN(, ) , log lifetime y ( lnt) follows normal

distribution N(, ) , where and are the expected values of y and variance, respectively.
y (x) z
  x  x  z
0 1 1 2 2
z denotes percentile of N(0, ) , and  ln A,  H / k,   B.
0 1 2
The p percentile of the lifetime distribution, or B Life, is widely used in reliability engineering. The
P
point estimation of is described as
ln B
p
ˆ ˆ ˆ
ˆ
ln B   x  x  z ˆ .
p 0 1 1 2 2 p /100
Then the point estimates of the 5 percentile and 50 percentile of the lifetime distribution are given by
ˆ ˆ ˆ ˆ
ln B   x  x 1,64ˆ
5 0 1 10 2 20
ˆ ˆ ˆ
ˆ
ln B   x  x .
50 0 1 10 2 20
where, {x , x } denotes the Controlled storage condition ( 25 °C and 50 % RH )
10 20
A.1.3 Interval estimation for optical disk
ˆ
For interval estimation of ln B for an optical disk, one may consider only the lower bound. (100) %
p
ˆ
lower confidence bound of log lifetime ln B is given by the following equation.
p
ˆ ˆ ˆ
( ln B )  ln B  z Varln B )
p L p  /100 p
ˆ ˆ
where, Varln B  denotes variance of ln B (see Annex D)
p p
© ISO/IEC 2011 – All rights reserved 13

ˆ
ˆ ˆ
When  is relatively small, we can put Varln B  . Then the 95% lower confidence bound of B Life

p 5
becomes as follows.
ˆ ˆ ˆ
(B Life)  (exp(ln B ))  exp(ln B 1.64 Varln B  )
5 L
5 L 5 5
ˆ
ˆ
 exp(ln B 1.64 )
ˆ
NOTE In case a more precise analysis is required or a larger estimated  is found, the 95% lower confidence bound
of B should be analyzed according to Annex D.


A.1.4 Estimation of and using the least squares method
The multiple linear regression model for i th specimen is described as follows.
y   x  x  (i 1 ~ n)
i 0 1 1i 2 2i i
where,  denotes errors, and n denotes total number of specimens.
i
The estimate yˆ is given as
i
ˆ ˆ ˆ
yˆ   x  x .
i 0 1 1i 2 2 i
Also, the sum of the squared residual errors Se is computed as
n
ˆ
Se (y  y ) .
i i

i1
ˆ
The regression coefficients of y can be obtained by applying the least squares method to Se . The estimates
i
ˆ ˆ ˆ
 , and are obtained by solving 110 linear regression equations of group A, B, C, D and E.
0 1 2
ˆ
The estimate  of variance is given as follows.
(y  yˆ )
Se i i

ˆ  
(n 21) (n 21)
where n 21 is the number of degrees of freedom.
ˆ ˆ ˆ
ˆ
The estimated regression coefficients  ,  and and variance of residual errors  are obtained using
0 1 2
regression analysis of statistics software tools.
B Life, B Life and the 95% lower confidence bound of B Life are described as follows.
50 5 5
ˆ
B Life = exp (ln B )
ˆ ˆ ˆ
  x  x
= exp ( )
0 1 10 2 20
ˆ
B Life = exp (ln B )
ˆ ˆ ˆ
ˆ
= exp (  x  x 1,64 )
0 1 10 2 20
where, {x , x } denotes the Controlled storage condition ( 25 °C and 50 % RH )
10 20
14 © ISO/IEC 2011 – All rights reserved

Also, 95% lower confidence bound of B Life becomes
ˆ
(B Life)  exp(ln B 1.64ˆ ) , when ˆ is relatively small. (see A.1.3)
5 L
A.2 Data analysis steps for lifetime estimation
The following is an outline of steps to estimate the media lifetime using the least squares method for the
Eyring Method, as a function of ambient temperature and relative humidity.
1. For each specimen, ordered by increasing time to failure values, compute (via linear regression) the
predicted time to failure.
2. (Steps 2 and 3 are for data quality check)
For each stress condition, the specimens are ordered by increasing time to failure values in order to
determine the median rank of each specimen.
3. Plot the median rank versus time to failure on a lognormal graph. Verify that the fitting lines for all stress
conditions are reasonably parallel to one another.
NOTE In the case where the fitting lines are not determined to be reasonably parallel, the assumptions made in
Clause 7.1.2 shall be checked.
4. Multiple regression coefficients and the standard error can be calculated using the least squares method
across all data of the log failure times, which were obtained at the five or four stress conditions. This
calculation can be performed by multiple regression analysis of statistics software tools.
5. B Life, B Life and 95% lower confidence bound of B Life at the Controlled storage condition are
50 5 5
calculated using the multiple regression coefficients and standard error.
For the conventional acceleration factor method, in addition to above steps 1 to 3, following steps 4 to 7 are
used
4. Calculate regression coefficients using the log mean failure time.
5. Calculate acceleration factors from the difference between the estimated log mean at each stress
condition.
6. Calculate the normalized time to failure at the ambient condition for each specimen group using the
acceleration factors, and plot these data on a lognormal graph.
7. B Life, B Life and 95% lower confidence bound of B Life at the Controlled storage condition are
50 5 5
calculated using ˆ andˆ obtained from the fitting line.
NO
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