1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 18927:2013Imaging materials Recordable compact discsystems Method forestimating the life expectancybased on the effects oftemperature and relativehumidityBS ISO 18927:2013
2、 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18927:2013. It supersedes BS ISO 18927:2008 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography.A list of organizations represented on this committe
3、e can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013. Published by BSI Standards Limited 2013ISBN 978 0 580 80505 9 ICS 35.220.3
4、0; 37.040.99 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2013.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 18927:2013 ISO 2
5、013Imaging materials Recordable compact disc systems Method for estimating the life expectancy based on the effects of temperature and relative humidityMatriaux pour image Systmes de CD enregistrables Mthode destimation de lesprance de vie base sur les effets de la temprature et de lhumidit relative
6、INTERNATIONAL STANDARDISO18927Third edition2013-03-01Reference numberISO 18927:2013(E)BS ISO 18927:2013ISO 18927:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized other
7、wise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCa
8、se postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 18927:2013ISO 18927:2013(E) ISO 2013 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Purpose a
9、nd assumptions 44.1 Purpose 44.2 Assumptions 45 Measurements . 45.1 Summary 45.2 Block error rate (BLER). 45.3 Test equipment . 55.4 Test specimen . 56 Accelerated stress test plan 66.1 General . 66.2 Stress conditions . 76.3 Accelerated test cell sample population . 96.4 Time intervals . 106.5 Test
10、 plan . 106.6 Measurement conditions . 107 Data evaluation .107.1 Lognormal distribution model . 107.2 Eyring acceleration model . 117.3 Acceleration factors . 127.4 Survivor analysis 127.5 Aids 128 Disclaimer 12Annex A (informative) Step analysis outline .13Annex B (informative) Example of test pla
11、n and data analysis 14Bibliography .26BS ISO 18927:2013ISO 18927:2013(E)ForewordISO (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 techn
12、ical 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
13、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 Inte
14、rnational 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
15、 be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 18927 was prepared by Technical Committee ISO/TC 42, Photography.This third edition cancels and replaces the second edition (ISO 18927:2008), of which it constitutes a minor revision
16、.The following change has been made to the second edition: An update of the bibliographical references.iv ISO 2013 All rights reservedBS ISO 18927:2013INTERNATIONAL STANDARD ISO 18927:2013(E)Imaging materials Recordable compact disc systems Method for estimating the life expectancy based on the effe
17、cts of temperature and relative humidity1 ScopeThis International Standard specifies a test method for estimating the life expectancy of information stored on recordable compact disc systems. Only the effects of temperature and relative humidity on the media are considered.This International Standar
18、d does not cover the effects of light, air pollution, or time-dependent flow phenomena.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For
19、undated references, the latest edition of the referenced document (including any amendments) applies.ISO/IEC 101491), Information technology Data interchange on read-only 120 mm optical data disks (CD-ROM)IEC 60908, Audio recording Compact disc digital audio systemExperimental statistics, U.S. Natio
20、nal Bureau of Standards Handbook 91, 19633 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1baselinecondition representing the disc at time of manufactureNote 1 to entry: This is customarily the initial parameter measurement taken prior to any appl
21、ication of stress. The designation is usually t = 0 for a stress time equal to zero hours.3.2block error rateBLERratio of erroneous blocks to total blocks measured at the input of the first (C1) decoder (before any error correction is applied)Note 1 to entry: The more commonly reported value for BLE
22、R is the number of erroneous blocks per second measured at the input of the C1-decoder during playback at the standard (1X) data rate.IEC 609083.2.1maximum block error ratemax BLERmaximum BLER measured anywhere on a disc1) Equivalent to ECMA 130. ISO 2013 All rights reserved 1BS ISO 18927:2013ISO 18
23、927:2013(E)3.3compact disc-recordableCD-Rrecordable optical disc in which information can be recorded to certain areas in compact disc formatNote 1 to entry: Information can be recorded once and read many times.Note 2 to entry: The term “compact disc-write once” (CD-WO) has also been used to describ
24、e this type of disc.3.4cumulative distribution functionFt()probability that a random unit drawn from the population fails by time t, or the fraction of all units in the population which fails by time t3.4.1lognormal cumulative distribution functionFt()cumulative distribution function in which the lo
25、garithm of the relevant parameter, in this International Standard the disc lifetime, has a normal distribution and is defined by the following equation:Ftxxt x()()ln()=1210122piledllwheret is the time;x is a variable representing disc lifetime;lis the log standard deviation;lis the log mean;ln(x) is
26、 the natural logarithm of xNote 1 to entry: When t =e1, the lognormal cumulative distribution function evaluates to 0,5. In other words, the model predicts that half the samples have failed at that time.3.5disc-at-once recordingmethod of recording a CD-R disc whereby the entire CD is recorded in one
27、 pass without turning off the laser3.6end-of-lifeoccurrence of any loss of information3.7extended-term storage conditionsstorage conditions suitable for the preservation of recorded information having permanent value3.8glass transitionreversible change in an amorphous polymer from, or to, a viscous
28、or rubber condition to, or from, a hard and relatively brittle one2 ISO 2013 All rights reservedBS ISO 18927:2013ISO 18927:2013(E)3.8.1glass transition temperatureTgapproximate mid-point of the temperature range over which glass transition takes placeNote 1 to entry: Tgcan be determined readily only
29、 by observing the temperature at which a significant change takes place in a specific electrical, mechanical, or other physical property.Note 2 to entry: Tgcan also be sensitive to the moisture content of the polymer.3.9informationsignal or image recorded using the system3.10life expectancyLElength
30、of time that information is predicted to be acceptable in a system after dark storage at 23 C and 50 % relative humidity (RH)3.10.1standardized life expectancySLEminimum life span, predicted with 95 % confidence, of 95 % of the product stored at a temperature not exceeding 25 C and a relative humidi
31、ty (RH) not exceeding 50 % RH3.11retrievabilityability to access information as recorded3.12stressexperimental variable to which the specimen is exposed for the duration of the test intervalNote 1 to entry: In this International Standard, the stress variables are confined to temperature and relative
32、 humidity.3.13survivor functionRt()probability that a random unit drawn from the population survives at least time t, or the fraction of all units in the population which survive at least time tNote 1 to entry: Rt Ft() ().=13.14systemcombination of material, hardware, software, and documentation nec
33、essary for recording and/or retrieving information3.15test celldevice that controls the stress to which the specimen is exposed3.16track-at-once recordingmethod of recording a CD-R disc whereby each track is recorded individually with 150 empty sectors immediately preceding it and two run-out sector
34、s immediately following ISO 2013 All rights reserved 3BS ISO 18927:2013ISO 18927:2013(E)3.17uncorrectable errorerror in the playback data that is not correctable by the cross interleave Reed-Solomon code defined in IEC 60908 as implemented in a system4 Purpose and assumptions4.1 PurposeThe purpose o
35、f this International Standard is to establish a methodology for estimating the life expectancy of information stored on recordable compact disc systems. This methodology provides a technically and statistically sound procedure for obtaining and evaluating accelerated test data.The methodology deals
36、only with the effects of temperature and humidity on the retrievability of stored information. For this reason, this International Standard is primarily directed to those storage applications, e.g. libraries and archives, in which exposure to other influences potentially detrimental to information l
37、ife expectancy, such as chemical agents, intense light sources, and improper handling, is controlled and minimized.4.2 AssumptionsThe validity of the procedure defined by this International Standard relies on three assumptions: specimen life distribution is appropriately modelled by the lognormal di
38、stribution; the kinetics of the dominant failure mechanism is appropriately modelled by an Eyring acceleration model; the dominant failure mechanism acting at the usage condition is the same as that at the accelerated conditions.Publications by Hamada and Stinson provide data indicating that these a
39、ssumptions are applicable to compact disc-recordable (CD-R) systems (see references5and6in the Bibliography).5 Measurements5.1 SummaryA sampling of 80 recorded discs shall be divided into five groups according to a specified plan. Each group of discs (test cell) shall be subjected to one of five tes
40、t stresses, combinations of temperature and relative humidity. Periodically during the stress conditions, all discs from each stress group shall have their block error rate (BLER) measured. Data collected at each time interval for each individual disc are then used to determine a lifetime for that d
41、isc.The disc lifetimes at each stress level are fitted to a lognormal distribution to determine a mean lifetime for the stress. The resulting five mean lifetimes are regressed against temperature and relative humidity according to an Eyring acceleration model. This model is then used to estimate the
42、 distribution of lifetimes at a usage condition.5.2 Block error rate (BLER)End-of-life is the occurrence of any loss of information. Ideally, each specimen is tested until the first loss of information occurs. Realistically, this is impractical. This International Standard considers max BLER to be a
43、 high-level estimate of the performance of the system. The objective of measuring BLER is to establish a practical estimation of the systems ability to read recorded data without uncorrectable errors. A change in max BLER in response to the time at an accelerated temperature and humidity is the prin
44、cipal quality parameter.4 ISO 2013 All rights reservedBS ISO 18927:2013ISO 18927:2013(E)IEC 60908 states that the BLER averaged over any 10 s shall be less than 3 102. At the standard (1X) data rate, the total number of blocks per second entering the C1-decoder is 7 350. Thus, an equivalent limit on
45、 BLER is 220 blocks per second.A BLER of 220 is an arbitrary level chosen as a predictor of the onset of uncorrectable errors and thereby end-of-life. A BLER of 220 corresponds to an upper limit for error correction. As a result, lower BLER discs are recommended to use for long-term storage.5.3 Test
46、 equipment5.3.1 General requirementsA compact disc player that conforms to ISO/IEC 10149 and software capable of producing a display of max BLER.If it becomes necessary to replace the test equipment, the US National Bureau of Standards Handbook 91 shall be followed for correlating test equipment out
47、puts.The make, model, and version of the test equipment (including software) shall be reported with the test results.5.3.2 Calibration and repeatabilityCalibration according to the tester manufacturers procedure shall be performed prior to any measurement data being collected. A calibration disc sha
48、ll be available from an accredited source.In addition to the calibration disc, one control disc shall be maintained at ambient conditions and its max BLER measured before and after each data collection interval. A control chart shall be maintained for this control disc.The mean and standard deviatio
49、n of the control disc shall be established by collecting at least five measurements. Should any individual max BLER 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.5.4 Test specimen5.4.1 General requirementsA test specimen is any disc that, after recording, meets ISO/IEC 10149 specifications and contains representative data extending to within 2 mm of the maximum recor
