1、BS ISO 2709:2008ICS 01.140.20; 35.240.30NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDInformation anddocumentation Format for informationexchangeThis British Standardwas published underthe authority of theStandards Policy andStrategy Committee on 30September 2
2、008 BSI 2008ISBN 978 0 580 56057 6Amendments/corrigenda issued since publicationDate CommentsBS ISO 2709:2008National forewordThis British Standard is the UK implementation of ISO 2709:2008. Itsupersedes BS ISO 2709:1996 which is withdrawn.The UK participation in its preparation was entrusted to Tec
3、hnicalCommittee IDT/2/7, Computer applications in information anddocumentation.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correc
4、t application.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS ISO 2709:2008Reference numberISO 2709:2008(E)ISO 2008INTERNATIONAL STANDARD ISO2709Fourth edition2008-07-01Information and documentation Format for information exchange Information et documentation Forma
5、t pour lchange dinformation BS ISO 2709:2008ISO 2709:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on th
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8、rm the Central Secretariat at the address 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
9、 permission in writing from either ISO 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
10、 reservedBS ISO 2709:2008ISO 2709:2008(E) ISO 2008 All rights reserved iiiForeword 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 te
11、chnical 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 close
12、ly 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
13、 International 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 docume
14、nt may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 2709 was prepared by Technical Committee ISO/TC 46, Information and documentation, Subcommittee SC 4, Technical interoperability. This fourth edition cancels and replaces the
15、third edition (ISO 2709:1996), which has been technically revised to incorporate specification of the use of ISO/IEC 10646 using 8-bit Unicode Transformation Format (UTF-8) encoding. Consequently, lengths are specified in terms of octets instead of characters. BS ISO 2709:2008BS ISO 2709:2008INTERNA
16、TIONAL STANDARD ISO 2709:2008(E) ISO 2008 All rights reserved 1Information and documentation Format for information exchange 1 Scope This International Standard specifies the requirements for a generalized exchange format which will hold records describing all forms of material capable of bibliograp
17、hic description as well as other types of records. It does not define the length or the content of individual records and does not assign any meaning to tags, indicators or identifiers, these specifications being the functions of an implementation format. This International Standard describes a gene
18、ralized structure, a framework designed specially for communications between data processing systems and not for use as a processing format within systems. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the
19、 edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO/IEC 646:1991, Information technology ISO 7-bit coded character set for information interchange ISO/IEC 6429:1992, Information technology Control functions for coded c
20、haracter sets ISO/IEC 10646:2003, Information technology Universal Multiple-Octet Coded Character Set (UCS) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 character member of a set of elements used for the organization, control, or represent
21、ation of data 3.2 data field characters recording the descriptive content of the record 3.3 directory index to the location of the fields within a record 3.4 directory map set of parameters specifying the structure of the entries in the directory BS ISO 2709:2008ISO 2709:2008(E) 2 ISO 2008 All right
22、s reserved3.5 field variable length portion of the record containing a particular category of data, following the directory and associated with one entry of the directory NOTE A field can contain one or more subfields. 3.6 field separator control character that terminates the directory, record ident
23、ifier, reference fields and data fields 3.7 tag three octets associated with a field and used to identify it 3.8 indicator first data element, if present, associated with a field supplying further information about the contents of the field, about the relationship between the field and other fields
24、in the record, or about the action required in certain data manipulation processes 3.9 octet group of 8 consecutive bits also referred to as an 8-bit byte; it may represent one character or be part of a representation of a character 3.10 record collection of fields, including a record label, a direc
25、tory and data NOTE If required, the linking of records and their division into subrecords is allowed and should be implemented as specified in the explicit exchange format. 3.11 record identifier field characters identifying the record 3.12 record label section occurring at the beginning of each rec
26、ord providing parameters for the processing of the record 3.13 record separator control character that terminates the record 3.14 reference field data that may be required for processing a record 3.15 separating character control character used to separate and qualify units of data logically, and in
27、 some cases hierarchically 3.16 structure arrangement of the parts constituting a record 3.17 subfield part of a field containing a defined unit of information BS ISO 2709:2008ISO 2709:2008(E) ISO 2008 All rights reserved 33.18 identifier data element of one or more characters immediately preceding
28、and identifying a subfield 3.19 subrecord group of fields within a record which may be treated as an entity 4 Structure of communication format for a record 4.1 General The general structure of a record is shown schematically in Figure 1. A more detailed structure is shown schematically in Figure 2,
29、 which includes four alternatives for the data sections. Record label Directory Fields Record separator Figure 1 General structure A record contains the following fixed and variable-length elements in the sequence shown in Figure 2: a) record label (fixed length); b) directory (variable length); c)
30、record identifier field (variable length); d) reference fields (variable length); e) data fields (variable length); f) field separator(s); g) record separator. The directory, record identifier, reference fields and data fields shall each be terminated by a field separator, i.e. separator IS2 in acco
31、rdance with lSO/IEC 646 or lSO/IEC 6429. The record shall be terminated by the record separator, i.e. separator IS3 in accordance with ISO/IEC 646 or lSO/IEC 6429. 4.2 Basic character encoding All data in the record label and directory, and the indicators, subfield identifiers, field separators, and
32、 record separators, shall be taken from the character repertoire of ISO/IEC 646, with one octet per character encoding as specified in ISO/IEC 646 or ISO 10646 with UTF-8 encoding. 4.3 Record label 4.3.1 General The record label shown in Figure 2 shall be fixed in length to 24 octets, each represent
33、ing one character and the octet positions shall be as defined in 4.3.2 to 4.3.9. BS ISO 2709:2008ISO 2709:2008(E) 4 ISO 2008 All rights reserved4.3.2 Record length (octets 0 to 4) The record length shall be defined by the number of octets in the record, including the record label, directory, fields,
34、 and the record separator. The length is a five-digit decimal number, right-aligned with zero fill if necessary. NOTE The record length described here is a logical record length. For practical reasons relating to machine processing of data, it is sometimes necessary to divide the information into bl
35、ocks. 4.3.3 Record status (octet 5) The record status shall be defined by a single character, to be defined in an implementation International Standard, describing the status of a record, for example new or amended. In the absence of an International Standard, special agreement should be reached bet
36、ween the interchange partners. 4.3.4 Implementation codes (octets 6 to 9) The implementation codes are not defined in this International Standard. Special agreement should be reached between the interchange partners. 4.3.5 Indicator length (octet 10) The indicator length shall be defined by one deci
37、mal digit giving the number of octets of the indicators. If indicators are not used, the indicator length shall be set to zero. 4.3.6 Identifier length (octet 11) The identifier length shall be defined by one decimal digit giving the number of octets of the identifier. The first or only character of
38、 this identifier shall always be IS1 in accordance with lSO/IEC 646 or ISO/IEC 6429. If the identifier is not used, the identifier length shall be set to zero. 4.3.7 Base address of data (octets 12 to 16) The base address of data shall be defined by five decimal digits, right-aligned with zero fill
39、if necessary, equal to the combined length in characters of the record label and the directory, including the field separator at the end of the directory. 4.3.8 Positions defined by user systems (octets 17 to 19) Octets positions 17 to 19 shall be defined by user systems. 4.3.9 Directory map The dir
40、ectory map positions shall be defined by the following. a) Octet 20: one decimal digit equal to the length in characters of the length of field part of each entry in the directory. b) Octet 21: one decimal digit equal to the length in characters of the starting character position part of each entry
41、in the directory. c) Octet 22: one decimal digit equal to the length in characters of the implementation-defined part of each entry in the directory. d) Octet 23: reserved for future use. BS ISO 2709:2008ISO 2709:2008(E) ISO 2008 All rights reserved 54.4 Directory 4.4.1 General The directory shall c
42、onsist of a variable number of entries, each corresponding to its respective field (record identifier, reference and data fields). The directory shall end with a field separator. 4.4.2 Directory entry An entry shall consist of the following parts in the given order: a) a tag; b) the length of the fi
43、eld; c) the starting character position; d) the implementation-defined part. The length of the tag shall be three octets. The length in octets of the other three parts in each directory entry shall be given by the directory map (octets 20 to 22 in the record label). All entries in a directory shall
44、have the same structure. 4.4.3 Tag The tag shall consist of three octets which specify, according to definition in an implementation International Standard, the name of any associated field. In the absence of an International Standard, special agreement shall be reached between the interchange partn
45、ers. 4.4.4 Length of field This length shall be either a) the total number of octets including indicator(s) and field separator in the field indicated by the preceding tag, or b) zero, implying that the directory entry refers to a field whose total length is greater than the largest decimal number (
46、n) which can be stored in the “length” of field part of a directory entry (see Note), or c) the number of octets (including field separator) in the final part of a field which has been treated as described in b). NOTE In the case of b), the field is regarded as being divided into a number of parts,
47、of which all but the last are of equal length (n). Each part has a corresponding directory entry containing the tag for the field and the starting character position of the part to which the directory entry refers. A length of zero indicates that the directory entry refers to a part of the field whi
48、ch is not the final part and that the length of this part is to be taken as (n). In the cases described in b) and c), all directory entries which refer to parts of the same field shall be adjacent and in sequence. 4.4.5 Starting character position The starting character position shall consist of a d
49、ecimal number giving the position of the first octet of the field identified by the preceding tag, relative to the base address of data i.e. the starting character position of the first field following the directory is 0 (zero). BS ISO 2709:2008ISO 2709:2008(E) 6 ISO 2008 All rights reserved4.4.6 Implementation-defined part The implementation-defined part of the entry, if present, shall contain control information relative to the field referenced by the entry. 4.5 Fields 4.5.1 General All fields shall end with a field separator. T
