1、 Reference number ISO 23868:2008(E) ISO 2008INTERNATIONAL STANDARD ISO 23868 First edition 2008-10-15 Document management Monitoring and verification of information stored on 130 mm optical media Gestion de documents Surveillance et vrification de linformation stocke sur des supports optiques de 130
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5、ss given below. COPYRIGHT PROTECTED DOCUMENT ISO 2008 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
6、at the address below or ISOs 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 copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reservedISO 23868:2008(E) ISO 2008 All
7、 rights reserved iii Foreword ISO (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 technical committees. Each member body interested in a
8、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 with the International Electrotechnical Commission
9、 (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 International Standards adopted by the technical com
10、mittees 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 be the subject of patent rights. ISO shall not
11、 be held responsible for identifying any or all such patent rights. ISO 23868 was prepared by Technical Committee ISO/TC 171, Document management applications, Subcommittee SC 1, Quality. ISO 23868:2008(E) iv ISO 2008 All rights reservedIntroduction Many organizations now use optical media for long-
12、term storage of information. It is assumed that a disk selected for recording has already been qualified for that purpose. It is therefore important to be able to verify that data have been recorded correctly and remain readable for the required amount of time. Previous ISO Standards clearly specifi
13、ed requirements for interchange, and methods for predicting the lifetime of optical media but did not contain methods for validation of the quality of written data. Longevity is limited both by media degradation and by technology obsolescence. Interchange needs to be regularly verified to assure tha
14、t information on existing recorded media will continue to be recoverable. Users can have a maintenance policy that protects disks against unanticipated failure or use, such as by making one archival copy, another to function as a backup or master, and another for routine access. Hardware support lif
15、ecycles typically vary between 5 years to 10 years and technology lifecycles usually end after 20 years. Consequently, recordings that require a longer lifecycle might have to be transferred to upgraded platforms every 10 years to 20 years. Optical media for long-term storage should be evaluated. Si
16、gnificant longevity differences can exist for disks from different media manufacturers and also between disks from the same media manufacturer. Degradation can be more rapid for disks of very poor initial quality than for high quality recordings. Disks with an initially poor quality do not offer suf
17、ficient headroom to avoid reaching the unrecoverable error threshold before the next scheduled inspection, which for archival disks is to be avoided. This means that a disk of high initial recorded quality that maintains this condition for life is expected to have superior longevity. Powerful cyclic
18、 redundancy check (CRC) error correction systems that are embedded in the disk and utilized by the drive can mask degradation. In the absence of drive standards, functionality does not allow the user to verify, in a simple manner, the quality of information recorded on a particular disk. Methods des
19、cribed in this International Standard specify a quality control policy that can non-destructively identify degradation, and thereby support timely and effective corrective action. INTERNATIONAL STANDARD ISO 23868:2008(E) ISO 2008 All rights reserved 1 Document management Monitoring and verification
20、of information stored on 130 mm optical media 1 Scope This International Standard specifies test methods to determine the quality of data on recorded media and provides specifications enabling end-user organizations to monitor data quality and ongoing conformance with the error limits required for i
21、ts class identified by the manufacturer of the drive/media. This International Standard defines error rate monitoring capabilities and procedures associated with 130 mm optical media while being used in a production environment to ensure that data are still readable throughout the expected life of t
22、he media. 2 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 12651, Elect
23、ronic imaging Vocabulary ISO/IEC 17345, Information technology Data interchange on 130 mm rewritable and write once read many ultra density optical (UDO) disk cartridges Capacity: 30 Gbytes per cartridge First generation ISO/IEC 11976, Data interchange on 130 mm rewritable and write-once-read-many u
24、ltra density optical (UDO) disk cartridges Capacity: 60 Gbytes per cartridge Second generation 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 12651, ISO/IEC 17345, ISO/IEC 11976, and the following apply. 3.1 end-of life EOL loss of interchange where
25、by information cannot be reliably retrieved 4 Test method 4.1 General The method specified in this International Standard to determine the quality of data on recorded media is based on a knowledge of the error correcting codes used to correct for inevitable media defects and the deterioration during
26、 normal life of the media. At the time of writing, the data should be verified by the writing system. During this verification process, the level of defects shall be checked and only data which require a small percentage of the error correction capability shall be accepted by the writing system. Thi
27、s International Standard defines a method for subsequent analysis of the remaining error correction capability when the ISO 23868:2008(E) 2 ISO 2008 All rights reservedmedia are read on a reference drive. In addition, the performance of the servos on the media shall be checked to determine if any un
28、acceptable media distortion has occurred. 4.2 Calibration of test drive The drive manufacturer provides reference disks, that have been checked on calibrated equipment. These media shall be provided with a test report documenting the acceptable range of results that shall be obtained when scanned on
29、 a drive to be used for archive data scanning. Any drive used to perform the media quality tests shall pass the check with reference media. 4.3 Test parameters The remaining error correction capability and servo performance of the media that are scanned shall be measured using a media scan. In order
30、 to keep the scan to a manageable time, a percentage of the surface shall be scanned. During the scan of a disk, the following operations shall be performed. a) The surface of the media shall be scanned to determine the location of written sectors. b) A minimum of every tenth track of user written d
31、ata shall be read and the number of errors in each code word calculated so as to ensure that there is sufficient remaining correction capability in the written sectors. The user may select to scan 100 % of the data depending on the value attributed to the content of the media. c) If 75 % of the avai
32、lable error correction capability in any sector tested is required to recover valid data, the media shall be reported as being at risk. In this case, the first measure shall be to clean the media according to the manufacturers instructions and to rescan for defects. If the same error is reported, th
33、e data should be migrated within 2 years of the date of testing. d) The servo channels shall be monitored to verify that none of the allowable thresholds are exceeded, for example due to surface dust or scratches. The maximum servo disturbances are defined in the relevant ISO specification for the m
34、edia type (ISO/IEC 17345, ISO/IEC 11976). In this case, the first measure shall be to clean the media according to the manufacturers instructions and to rescan for defects. If the same error is reported, the data should be migrated within two years of the date of testing. e) The sector addresses sha
35、ll be checked to ensure that at least one ID field in every sector is readable without errors. If this condition is not met, the media shall be reported as being at risk. In this case, the first measure shall be to clean the media according to the manufacturers instructions and to rescan for defects
36、. If the same error is reported, the data should be migrated within two years of the date of testing. f) The remaining spares area shall be checked to ensure that the relocation rate is acceptable. Less than 50 % of the spares allowed shall have been used. The spares allowed shall be allocated in pr
37、oportion to the percentage of the user area written. If this condition is not met, the media shall be reported as being at risk. In this case, the first measure shall be to clean the media according to the manufacturers instructions and to rescan for defects. If the same error is reported, the data
38、should be migrated within two years of the date of testing. 4.4 Test set-up Before testing a media cartridge, the drive to be used shall be calibrated using reference media supplied by the drive manufacturer. The cartridge to be tested should be inspected for physical damage but no attempt should be
39、 made to clean the media surface. In general, media cleaning is detrimental to performance unless carried out using the correct materials to a specification. Only in the event of a disk cartridge failing the scan, should the media be cleaned. See informative Annex A for recommendations on disk clean
40、ing. Disk cleaning should only be performed using the recommended disk cleaner and cleaning fluid supplied by the media vendor. On no account shall the user disassemble the disk cartridge. ISO 23868:2008(E) ISO 2008 All rights reserved 3 4.5 Procedure The tester shall use a software application, cer
41、tified by the drive manufacturer to accurately identify media errors on certified media to verify certified media on a drive connected to a computer via a computer interface. The tester shall be able to enter a disk serial number and this shall be added to the test file generated by the test. Before
42、 testing media, verify the system by checking the reference media supplied with the test drive. Insert the reference disk into the drive, and then execute the “system check” option. The drive shall read the calibration file from the reference disk and perform a media scan of the identified sectors.
43、The results of this scan shall be compared with the calibration file to ensure that the drive correctly identifies defective sectors. At the end of the calibration check, the test results shall be written on the calibration disk for future analysis. If the drive passes the calibration check, insert
44、the disk to be checked into the test drive. The application shall read the unique media ID written at the time of manufacture and shall be able to display this to the operator. In the event that these media have previously been checked using the test application, the previous test file shall be retr
45、ieved and used to check the rate of deterioration of data quality. When prompted, enter a text comment, which is appended to the test file. Execute the test application, scanning the media for written sectors. A percentage of these sectors as specified in 4.3 shall then be read and an analysis of th
46、e error correction status shall be made on a sector-by-sector basis as follows. The test application shall be used to analyse the user data and check the number of errors in each error correcting code word to ensure that there is sufficient residual error correction capability as specified in 4.3. T
47、he quality of the embossed address information shall be checked as specified in 4.3 to ensure reliable access without the implementation of recovery routines. The servo channels shall be monitored as specified in 4.3 to determine if the focus or tracking error exceeds the limits allowed in the media
48、 specification. At the end of the test, a test file shall be written to a specified disk drive on the host PC. Based on the analysis of the defects found during the scan, the application shall report the status to the user. 4.6 Test result evaluation As indicated in the preceding section, the test a
49、pplication shall automatically generate a test file and recommendations for action required. There are three possible results from tests executed as specified in 4.5 as follows. a) Disk cleaning is recommended after which the disk shall be re-tested. b) The data have reached end of life and should be copied to new media. This result is only reported if media have been retested after cleaning. This is determined by the existence of two successive file records for the media concerned where the media fail one of the following criteri
