1、7 -ENGL 1999 0724150 055b3b2 922 = ANSUPIMA IT9.27-1 for Imaging Materials - Life Expectancy of Information Stored in Recordable Compact Disc Systems - Method for Estimating, Based on Effects of Temperature and Relative Humidity 999 - -m mmn Na1 American National Standards Institute I I West 42nd St
2、reet New York, Nau York I0036 - STD-ANSI IT9.27-ENGL 1999 m 0724350 055b3b3 Bb m ANSVPIMA lT9.27-1999 American National Standard for Imaging Materials - Life Expectancy of Information Stored in Recordable Compact Disc Systems - Method for Estimating, Based on Effects of Temperature and Relative Humi
3、dity Secretariat Photographic their existence does not in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does
4、not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interp
5、retations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodi
6、cally to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Standard Published by American National Standards Institute, Inc. 11 West 42nd Street, New
7、 York, NY 10036 Copyright O 2000 by American National Standards Institute All rights reserved. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher. Printed in the United States of America Content
8、s Page Foreword i 1 Scope . 1 2 Normative references . 1 3 Definitions . 2 4 Measurements 4 5 Accelerated stress test plan . 5 6 Data evaluation . 10 7 Disclaimer . 15 Tables 1 2 Figure 1 Annexes A Ten-step analysis outline 13 B Example of test plan and data analysis 14 C Bibliography 27 Temperature
9、 and relative humidity ramp profile . 7 Summary of stress conditions 9 Graph of nominal 80C/85% RH ramp profile 8 I STD-ANSI IT9.27-ENGL 1999 m 072qL50 055b3bb 578 m Foreword (This foreword is not part of American National Standard ANSVPIMA lT9.27-1999.) This standard was prepared by the Joint Techn
10、ical Commission of PIMA IT9-5 on Optical - Sample life distribution is appropriately modeled by the lognormal distribution; - The kinetics of the dominant failure mechanism is appropriately modeled by an Eyring acceleration model; - The dominant failure mechanism acting at the usage condition is the
11、 same as that at the accelerated conditions. Publications by Hamada l” and Stinson 2 provide data indicating that these assumptions are applicable to CD-R systems. 2 Normative references The following American Standards contain provisions which, through reference in this text, constitute provisions
12、of this American National Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most - ) The number in the bracke
13、ts refers to the reference in clause 2. 1 ANSI/PIMA lT9.27-1999 recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid Standards. ISO/IEC 908: 1987, Compact disc digital audio systed ISO/IEC 1 O1 49:1995, Information technology - Data interchan
14、ge on read-only 120 mrn optical data disks (CD-ROM) *) l Hamada, E., Taiyo Yuden: Technologie et Fiabilite du CD-WORM. Memoires optiques 1990 5 Murray, W. P., Accelerated service life predictions of compact disks. ASTM STP 1202: 263- 271 ; 1994 6 Tobias, P. A. and Trindade, D. C., Applied reliabilit
15、y. New York: Van Nostrand Reinhold; 1986 (A second edition issued in 1995.) 3 Definitions For the purpose of this standard, the following definitions apply. 3.1 baseline: Initial parameter measurement taken prior to any application of stress. 3.2 block error rate (BLER): As defined in ISO/IEC 908, B
16、LER is the ratio of erroneous blocks to total blocks measured at the input of the first (Cl) decoder (before any error correction is applied). The more commonly reported value for BLER is the number of erroneous blocks per second measured at the input of the C1-decoder during playback at the standar
17、d (1X) data rate. 3.2.1 maximum block error rate (max BLER): Maximum BLER measured anywhere on a disc. 3.3 compact disc-recordable (CD-R): Recordable disc which, after recording, satisfies the specifications as written in the disc parameters clause (clause 2) of ISO/IEC 908. The term, compact disowr
18、ite once (CD-WO), has also been used to describe this type of disc. 3.4 cumulative distribution function, F(t): Fraction of all units in the population that fail by time t. Also, the probability that a random unit drawn from the population fails by time t. 3.5 disc-at-once recording: Method of recor
19、ding a CD-R disc whereby the entire CD is recorded in one pass without turning off the laser. 3.6 end-of-life: Occurrence of any loss of information. - 2, For electronic copies of some standards, visit ANSIs Electronic Standards Store (ES) at www.ansi.org. For printed versions of all these standards
20、, contact Global Engineering Documents, 15 Inverness Way East, Englewood, CO 801 12-5704, (800) 854-7179. 2 - - STD=ANSI IT9-27-ENGL 1999 = 0724150 0556370 TT9 H ANSVPIMA lT9.27-1999 3.7 glass transition temperature: As an amorphous polymer is warmed, many properties of the polymer (modulus, coeffic
21、ient of thermal expansion, dielectric loss, etc.) undergo dramatic change over a narrow temperature range. The midpoint of the temperature span over which this change in properties occurs is the glass transition temperature. 3.8 information: Signal or image recorded using the system. 3.9 life expect
22、ancy (LE): Length of time that information is predicted to be retrievable in a system under extended-term storage conditions. 3.9.1 standardized life expectancy: Minimum life span, predicted with 95% confidence, of 95% of product stored at a temperature not exceeding 25OC and a relative humidity not
23、 exceeding 50% RH. 3.1 O lognormal cumulative distribution function: It is defined by the following equation: where f is the time; 0, Pl is the log mean ioge(x) is the log standard deviation; is the natural logarithm of x NOTE - When t =epL the lognormal cumulative distribution function evaluates to
24、 0.5. In other words, the model predicts that at that time half of the samples have failed. 3.1 1 retrievability: Ready access to information as recorded. 3.12 stress: Experimental variable to which the specimen is exposed for the duration of the test interval. In this standard, stresses are confine
25、d to temperature and relative humidity. 3.13 survivor function, (q: Fraction of all units in the population that survive at least time f. Also, the probability that a random unit drawn from the population survives at least time f. R(f) = 1 - F(f) 3.14 system: Consists of recording medium, hardware,
26、software, and documentation necessary to retrieve information. 3.15 test cell: Device that controls the stress to which the specimen is exposed. 3.16 track-at-once recording: Method of recording a CD-R disc whereby each track is recorded individually with 150 empty sectors immediately preceding it a
27、nd two run-out sectors immediately following. 3.17 uncorrectable error: Error in the playback data that is not correctable by the Cross Inferleave eed-Solomon Code defined in ISO/IEC 908 (clause 16, error correction) as implemented in a system. 3 ANWPIMA lT9.27-1999 4 Measurements 4.1 Summary A samp
28、ling of eighty recorded discs is divided into five groups according to a specified plan. Each group of discs is exposed to one of five stresses, combinations of temperature and relative humidity. Periodically during the course of the exposure, all discs from each stress group have their block error
29、rate measured. Data collected at each test interval for each individual disc are used to determine a lifetime for that disc. The disc lifetimes at each stress are fitted to a lognormal distribution to determine a mean lifetime for the stress. The resulting five mean lifetimes are regressed against t
30、emperature and relative humidity according to an Eyring acceleration model. This model is then used to estimate the distribution of lifetimes at a usage condition. 4.2 BLER End-of-life is the occurrence of any loss of information. Ideally, each sample is tested until the first loss of information oc
31、curs. Realistically, this is impractical. This standard considers maximum BLER to be a 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 the recorded data without uncorrectable error. Change in
32、maximum BLER in response to the time at accelerated temperature and humidity is the principal quality parameter. ISOAEC 908 states that the BLER averaged over any 1 O seconds shall be less than 3x10“. At the standard (1X) data rate, the total number of blocks per second entering the C1- decoder is 7
33、350. Thus, an equivalent limit on BLER is 220 blocks/second. For the purposes of this standard, recorded data is considered to have reached end-of-life when the BLER, measured as erroneous blocks per second, exceeds 220 anywhere on the disc, i.e. when max BLER exceeds 220. It is recognized that the
34、correlation between actual loss of information and rnax BLER is very system dependent. A BLER of 220 is an arbitrary level chosen as a predictor of the onset of uncorrectable errors and thereby end-of-life. 4.3 Test equipment Any compact disc test system (tester) that conforms to ISOAEC 10149 may be
35、 used. The make, model, and version of the test equipment (including software) shall be reported with the test results. 4.3.1 Calibration and repeatability A calibration according to the tester manufacturers procedure shall be performed prior to any measurement data being collected. A calibration di
36、sc shall be available from the tester manufacturer. In addition to the calibration disc one control disc shall be maintained at ambient conditions, and its rnax BLER measured before and after each data collection interval. A control chart shall be maintained for this control disc. The mean and stand
37、ard deviation of the control disc shall be established by collecting at least five measurements. Should any individual rnax 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 shal
38、l be remeasured. If it becomes necessary to replace the tester, the National Bureau of Standards Handbook 91 3 shall be followed for correlating tester outputs. 4 STD=ANSI IT9-27-ENGL 3999 U 0724350 O556372 871 ANSIIPIMA lT9.27-1999 4.4 Test specimen A test specimen is any disc that, after recording
39、, meets ISOAEC 10149 specifications and contains representative data extending to within 2 mm of the maximum recording diameter 4.4.1 Specimen selection All discs shall be nominally identical with regard to substrate groove structure, layer structure, coating composition, recording capacity, and age
40、 prior to test initiation. It is preferred that media be chosen from different lots and production lines in order to be representative of normal process variations. All discs shall be maintained within manufacturers shipping and storage conditions prior to recording. The nominal disc capacity shall
41、be reported with the test results. 4.4.2 Recording system Sample discs may be recorded in any appropriate recording device. Since the extrapolated lifetime is a function of the system including the media, all discs shall be recorded identically to the extent possible. Similar recording devices shall
42、 be used as well as similar software and recording conditions. Discs recorded on different physical devices shall be distributed as equally as possible across the test cells. The make and model of the recording device, the linear velocity employed during recording, and the software used in the recor
43、ding system shall be reported with the test results. 4.4.3 Ambient recording conditions Ambient conditions during recording shall be within the following limits: Temperature: 15C to 35C Relative humidity: 45% RH to 75% RH. During recording, the recording system shall be isolated from external vibrat
44、ions. 4.4.4 Recording method It is strongly recommended that all discs be recorded using the disc-at-once method. If discs are recorded using the track-at-once method, all errors occurring at the gap between tracks shall be ignored for the purpose of this standard. Packet writing shall not be employ
45、ed. Independent of the writing method, the sample discs shall be recorded as a single session and fixated. 5 Accelerated stress test plan 5.1 Introduction Information properly recorded in a CD-R system of good manufacture should have a life of several years or even decades. Consequently, it is neces
46、sary to conduct accelerated aging studies in order to develop a life expectancy estimate. The key is conducting and evaluating a test plan that will provide the information necessary to satisfactorily evaluate the particular system. 5 ANWPIMA lT9.27-1999 Many accelerated life test plans follow a rat
47、her traditional approach in sampling, experimentation, and data evaluation. These traditional plans share the following characteristics: a) The total number of specimens is evenly divided amongst all of the accelerated stresses; b) Each stress is evaluated at the same time increments; c) The Arrheni
48、us relationship is used as the acceleration model; d) The Least Squares method is used for all regressions; e) The calculated life expectancy is for the mean or median life rather than for the first few failure percentiles. On the other hand, optimum test plans have been proposed which differ in sig
49、nificant aspects from traditional plans. These plans have the following characteristics: - two and only two acceleration levels for each stress; - a large number of specimen distributed mostly in the lowest stress levels; - the need to know the failure distribution, a priori, in order to develop the plan. The maximum effectiveness of a plan can either be estimated before the test starts or determined after the results have been obtained. As each CD-R system will have different characteristics, a specific, detailed optimum plan is impossible to f
