Information technology -- Digitally recorded media for information interchange and storage -- Test method for the estimation of the archival lifetime of optical media

ISO/IEC 10995:2011 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 can be applied to additional optical disk formats with the appropriate specification substitutions and can be updated in the future as required. ISO/IEC 10995:2011 includes - stress conditions, - assumptions, - ambient conditions: controlled storage conditions, e.g. 25 °C and 50 % RH, using the Eyring model; and uncontrolled storage conditions, e.g. 30 °C and 80 % RH, using the Arrhenius model, - evaluation system description, - specimen preparation, - data acquisition procedure, and - data interpretation.

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

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Published
Publication Date
16-Jun-2011
Current Stage
9020 - International Standard under periodical review
Start Date
15-Jul-2021
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INTERNATIONAL ISO/IEC
STANDARD 10995
Second edition
2011-06-15
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 10995:2011(E)
ISO/IEC 2011
---------------------- Page: 1 ----------------------
ISO/IEC 10995:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© 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,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2011 – All rights reserved
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ISO/IEC 10995:2011(E)
Contents Page

Foreword ............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ iv

1  Scope ...................................................................................................................................................... 1

2  Conformance ......................................................................................................................................... 1

3  Normative references ............................................................................................................................ 2

4  Terms and definitions ........................................................................................................................... 2

5  Conventions and notations .................................................................................................................. 3

5.1  Representation of numbers .................................................................................................................. 3

5.2  Names ..................................................................................................................................................... 3

6  Abbreviated terms ................................................................................................................................. 3

7  Measurements ....................................................................................................................................... 4

7.1  Summary ................................................................................................................................................ 4

7.2  Test specimen ........................................................................................................................................ 5

7.3  Recording conditions ............................................................................................................................ 5

7.4  Playback conditions .............................................................................................................................. 6

7.5  Disk testing locations ........................................................................................................................... 6

8  Accelerated stress test ......................................................................................................................... 7

8.1  General ................................................................................................................................................... 7

8.2  Stress conditions .................................................................................................................................. 7

8.3  Measuring Time intervals ..................................................................................................................... 9

8.4  Stress Conditions Design ..................................................................................................................... 9

8.5  Media Orientation .................................................................................................................................. 9

9  Data Evaluation ...................................................................................................................................... 9

9.1  Time-to-failure ........................................................................................................................................ 9

9.2  Eyring acceleration model (Eyring Method) ..................................................................................... 10

9.3  Data analysis ........................................................................................................................................ 10

Annex A (normative) Data Analysis Steps Outline for Calculation of Media Life ...................................... 11

Annex B (normative) Analysis for Calculation of Media Life ....................................................................... 12

Annex C (normative) Uncontrolled Ambient Condition Media Life Calculation ......................................... 22

Annex D (informative) Truncated Test Method (Determination of Media Life Lower Bound) ................... 23

Annex E (informative) Relation between BER and PI Sum 8 ........................................................................ 26

Bibliography ...................................................................................................................................................... 27

© ISO/IEC 2011 – All rights reserved iii
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ISO/IEC 10995:2011(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.

This second edition cancels and replaces the first edition (ISO/IEC 10995:2008), which has been technically

revised.
iv © ISO/IEC 2011 – All rights reserved
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ISO/IEC 10995:2011(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 document 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 Technical Committee 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 document.

ECMA-379 1 Edition was fast-tracked to ISO/IEC JTC 1 in August 2007 and during this process its editorial

content was slightly modified. The approved International Standard was published as ISO/IEC 10995:2008 in

nd rd

April 2008. ECMA-379 2 Edition is technically identical with ISO/IEC 10995:2008. ECMA-379 3 Edition is

an editorial amendment including corrections of some calculations, and the Bootstrap method has been

deleted. Although the Bootstrap method poses no problem in itself, miscalculation might be caused depending

on the data set conditions.
© ISO/IEC 2011 – All rights reserved v
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INTERNATIONAL STANDARD ISO/IEC 10995:2011(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 can be applied to additional

optical disk formats with the appropriate specification substitutions and can be updated in the future as

required.
This International Standard includes
 stress conditions,
 assumptions,
 ambient conditions,
 controlled storage conditions, e.g. 25 °C and 50 % RH, using the Eyring model,

 uncontrolled storage conditions, e.g. 30 °C and 80 % RH, using the Arrhenius model,

 evaluation system description,
 specimen preparation,
 data acquisition procedure, and
 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.

© ISO/IEC 2011 – All rights reserved 1
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ISO/IEC 10995:2011(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 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 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 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 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)

4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
4.1
archival (lifetime)

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
2 © ISO/IEC 2011 – All rights reserved
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ISO/IEC 10995:2011(E)
4.4
Eyring method

accelerated aging model based on the effects of temperature and relative humidity

4.5
error rate
rate of errors on the sample disk measured before error correction is applied
4.6
incubation
process of enclosing and maintaining controlled test sample environments
4.7
life expectancy

estimation of the length of time that information is predicted to be retrievable in a system while in a specified

environmental condition
4.8
maximum error rate

maximum of the error rate measured anywhere in one of the relevant areas on the disk.

NOTE For DVD-R/RW and +R/+RW, this is the Maximum PI Sum 8; for DVD-RAM, this is the Maximum BER.

4.9
retrievability
ability to recover physical information as recorded
4.10
stress

temperature and relative humidity variables to which the sample is exposed for the duration of test incubation

intervals
4.11
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 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 Abbreviated terms
BER byte error rate
LE life expectancy
PI parity (of the) inner (code)
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ISO/IEC 10995:2011(E)
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 its error rate after each stress condition incubation time interval. The control disk will 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 modeled by a statistical distribution,

 the Eyring model can be used to model acceleration with 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 retrievability of

the information is attempted,

 the recorded format will be recognizable and interpretable by the reading software.

7.1.3 Error Rate

Of all specimen media the Error rate shall be measured in the disk testing locations as defined in 7.5. For

each sample the Maximum error rate 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.

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.
4 © ISO/IEC 2011 – All rights reserved
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ISO/IEC 10995:2011(E)
7.1.3.2 BER

The number of erroneous symbols shall be measured at any in 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

specified in 7.5 shall not exceed 10 (See Annex E).
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 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 are entered into accelerated aging tests, they shall be recorded as optimally as is

practicable, according to the descriptions given in the format standards identified in Clause 3. OPC (optimum

power control) during the 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.

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 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.
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ISO/IEC 10995:2011(E)
7.4 Playback conditions
7.4.1 Playback tester

All media shall be read by the playback tester as specified in each of the format standards identified in

Clause 3 or equivalent, 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 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 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.
7.5 Disk testing locations

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. 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.
Table 1 — Nominal radii of the three test bands (Unit; mm)
DVD-R/RW, +R/+RW disk
DVD-RAM disk
(Single Layer/Dual Layer)
80mm 120mm 80mm 120mm
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
6 © ISO/IEC 2011 – All rights reserved
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ISO/IEC 10995:2011(E)
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
Minimum
Minimum
Test stress condition Number of Incubation Intermediate
equilibration
Test cell
(incubation) specimens duration RH
Total time
duration
number
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
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.

© ISO/IEC 2011 – All rights reserved 7
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Relative Humidity (%) (RH)
ISO/IEC 10995:2011(E)
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
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 equilibrium

int inc
moisture absorption in polycarbonate as that supported at T and RH
amb amb
Process step
T,RH RH Incubation RH Equilibration T,RH
Ramp Ramp Ramp Ramp
Temp.
End
Start
Time (Hour)
Figure 1 — Graph of typical transition (ramp) profile
8 © ISO/IEC 2011 – All rights reserved
Temperature (℃)
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ISO/IEC 10995:2011(E)
8.3 Measuring Time intervals

For data collection, PI Sum 8 (DVD–R, DVD–RW, +R, +RW), or BER (DVD-RAM) measurements for each

disk will occur: 1) before disk exposure to any stress condition to determine its baseline measurement and 2)

after each cycle 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 specifies the temperatures, relative humidities, time intervals, minimum total test time, and minimum

number of specimens for each stress condition. A separate group of specimens is used for each stress

condition.

All temperatures may deviate 2 °C of the target temperature; all relative humidities may deviate 3 % RH of

the target relative humidity.

The intermediate relative humidity (RH ) in Table 2 is calculated assuming 25 °C and 50 % RH ambient

int

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; RH is the ambient relative

amb inc amb
humidity;
RH is the intermediate relative humidity.
int

The stress conditions tabulated in Tables 2 and 3 offer sufficient combinations of temperature and relative

humidity to satisfy the mathematical requirements of the Eyring model to demonstrate linearity of either Max

PI Sum 8, or Max BER 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 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 error rate measurements.
9 Data Evaluation
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 val
...

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