Reliability of Long-term Storage for Compact Disc Media
Mitsuru Irie1, Kazuaki Nakajima1, Yumiko Tani1, Yoshihiro Okino2 and Takahiro Kubo3
1)

Faculty of Engineering, Osaka Sangyo Univ., 3-1-1 Nakagaito, Daito, Osaka, 574-8530 Japan
Phone: +81-72-875-3001, Fax: +81-72-8189, E-mail: irie@eic.osaka-sandai.ac.jp

2)

High Tech Research Center, Kansai Univ., 3-3-35 Yamate-cho, Suita, Osaka, 564-8680 Japan
3)
T. KUBO Eng. Sci. Office, 3-8-1 Higashinada, Kobe, Hyogo, 658-0072 Japan
ABSTRACTIn 1982, the history of the optical disk world started by CD-Audio. In this study, we have aimed to clarify

long-term storage characteristics of CD media (CD-Audio, CD-R). Playback characteristics of commercial CD-Audio
manufactured in around 1982 were evaluated and more the life expectancy of CD-R disks evaluate by using the Eyring
acceleration test, experimentally. The experimental result demonstrated that lifetime of a CD media is deemed to be
sufficiently long at general room condition.

KEYWORDS: Compact Disc, CD, reliability, archival data, Eyring acceleration model, life expectancy, optical disk1. Introduction
Since 1982, CD media has been widely used in the internet-digital information world, and been expected thelong-term and stability storage medium. A method of predicting the life expectancy ofDVD) has been established as the ISO or ISO/IEC standard.

optical disks (CD-ROM, CD-R,1-3)

In this study, the playback characteristics of commercial CD-Audio media, that manufactured in around 1982
(after that a long-term storage under general room condition), were evaluated. Figure 1 showed the history of thereliability study (lifetime, standard test method etc.) for optical media. This paper presents discussion of long-term
storage reliability for CD media and recent activity of estimating method for the archival life expectancy based on theISO/IEC standard.

2. Measurement Results of reliability for 1982’s CD-Audio media
Playback characteristics of commercial CD-Audio media manufactured in around 1982 were evaluated byusing the newest commercial drive. The measurement item of the lifetime criteria used the block error rate (BLER) of
the read-out digital signal, and the BLER averaged over any 10 seconds shall be less than 3×10-2.

At the standard datatransfer rate, the total number of blocks per second entering the C1-decoder is 7 350. Thus, the number of C1 errors persecond before error correction which is averaged over any 10 seconds shall not exceed 220.
Figure 2,3 shows experimental results of BLER measurements in archival (read-out) tests. A review of Fig. 2,

3 reveals that the BLER values of PC disks are very stable and not reach 220.

3.

Estimating archival life expectancy of 48X CD-R media
The basic construction of our evaluation systems is shown in Fig. 4. The criterion used for determining aCD’s failure time is the number of error of the BLER. The failure time is assumed to be the time at which the BLER
reaches criterion value, 220. The relation between the median ranks of lifetime data obtained for measurement and thenatural logarithm of the lifetime data are shown in Fig. 5. Verify that the plots for all stress conditions are reasonably
parallel to one another.
As for the method of predicting the life expectancy of ISO/IEC standard, the Eyring acceleration test model isadopted. The Eyring model simplified equation in terms of temperature and relative humidity ist  Ae H / kT e BRH
whereBoltzmann's(1)t is the failure time data, T is the temperature in Kelvin, R is therelative humidity, k is theconstant, ΔH is the activation energy, and A and B are constants.

Constants A, B, andΔH of eq. (1) were calculated using multiple linear regression analysis with failure time
data and the respective stress conditions of temperature and relative humidity.
Now, we investigated a simple estimating method for the archival life expectancy ofCD-R disks in order toapply a rough clarification of archival grade disks based on the ISO/IEC standard. Figure 6 shows the reliability
function (R(t) = 1-F(t)) under the 90% confidence interval. The life expectancy by the 95% confidence interval can bepresumed, when reliability (survival probability) is assumed as 95% at 25°C/50%RH.

4. Conclusions
This study examined the playback characteristics of commercial CD-Audio media that manufactured inaround 1982, and reported recent activity of estimating method for the archival life expectancy based on the ISO/IEC
standard. The experimental result demonstrated that lifetime of a CD media is deemed to be sufficiently long
general room condition.

Acknowledgement We would like to thank CDs21 solutions, Japan for supporting the work.

References
1)

ISO 18921: ” Compact discs (CD-ROM)- Method for estimating the life expectancy based on the effects oftemperature and relative humidity” (2002)．

2)

ISO 18927: ” Recordable compact disc systems- Method for estimating the life expectancy based on the effects oftemperature and relative humidity” (2002)．

3)

ISO/IEC 10995: “Test Method for the Estimation of the Archival Lifetime of Optical Media,” (2008).

at1980

1990

2000

2010

DVDCDBD1990
1st PCOS

1985 OITDA Working (Japan)
1987 ISO/TC97/SC23 (Japan)

1992-4
Research of Optical disk
Testing method(Hamamatu Project)

10 Years Study of Reliability
Phase Change (PD) disk

Test method ofArchival lif etime

2008.1
ISO/IEC 10995

Data migration
method f or DVD

2009.1
ISO/IEC 29121

Almost 30 Years Study of Reliability
CD-Audio（ ROM) disk

Figure 1 History of the reliability study for optical media.

Figure 2 Experimental results of BLER measurements in 1983’ CD-Audio (not for sale).

Figure 3 Experimental results of BLER measurements in 1982’ CD-Audio.

Evaluation systems

Acceleration tests

Statistical analysis
4Recording & Readout
evaluation

ChamberStress condition Sample Number①85℃/RH85％
20②85℃/RH70％
20③70℃/RH75％
20④65℃/RH85％
30

Probability Distribution

3,532,52
1,5Log normal
distribution

10,50
1E+05

2E+05

3E+05

4E+05

5E+05

6E+05

7E+05

Normalized Failure time (Hours)

Consumer drive

Cycle tests

Readout evaluation

Sampledisks

Estimating
the lif e expectancy

DDMDDM: DVD Data Checker (Pulstec)

Figure 4 Basic constructions of evaluation systems.

1.0
0.9

95%

90% Confidence intervals(lower level)

Survival probability

0.80.7

Survivor function

0.6
0.5

0.4
0.3
0.2
0.1
0.0
1.0E+072.0E+073.0E+07

4.0E+07

5.0E+07

6.0E+07

Hours to failure（h）

Figure 5. Relation between the median rank of lifetime Figure 6. Survival Probability function at 25°C/50%RH .
data and the natural logarithm of the lifetime data. .