Internet DRAFT - draft-hakala-istc
draft-hakala-istc
Network Working Group Juha Hakala
Internet-Draft Helsinki University Library
Category: Informational 3 July 2002
draft-hakala-istc-00.txt
Expires: 3 January 2003
Using International Standard Text Work Codes as
Uniform Resource Names
Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.
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This Internet-Draft will expire on 3 January 2003.
Abstract
This document discusses how International Standard Text Work Codes
(ISTCs; persistent and unique identifiers for textual works) can be
supported within the URN framework and the syntax for URNs defined in
RFC 2141 [Moats]. Analysis is in part based on the ideas expressed in
RFC 2288 [Lynch], which analysed the use of ISSN, ISBN and SICI as URNs.
Chapter 5 contains a URN namespace registration request modelled
according to the template in RFC 2611 [Daigle et al.].
1. Introduction
As part of the validation process for the development of URNs the IETF
working group agreed that it is important to demonstrate that the
current URN syntax proposal can accommodate existing identifiers from
well-established namespaces. One such infrastructure for assigning and
managing names comes from the bibliographic community. Bibliographic
identifiers function as names for objects that exist both in print and,
increasingly, in electronic formats. RFC 2288 [Lynch et. al.]
investigated the feasibility of using three identifiers (ISBN, ISSN and
ISTC) as URNs.
As a result of a recent proliferation of manifestations of works
(various printed and electronic versions of books, for instance) ISO has
decided to develop a set of identifiers for works. These standards
include International Standard Audiovisual Work Code (ISAN),
International Standard Musical Work Code (ISWC) and International
Standard Text Work Code (ISTC) [ISO].
These standards identify works (such as Brave New World by Aldous
Huxley) and their manifestations (such as a translation of Brave new
world into Finnish). Manifestations, like the first edition of the Brave
new world by Chatto & Windus, London 1932, will never receive an ISTC
but û it being a novel û an ISBN. ISTC and ISTC metadata will be
efficient tools for bringing together all related works and expressions
û like all translations of Brave new world û and all manifestations any
work or expression may have.
ISTC is an emerging ISO standard which will reach the status of a Draft
International Standard by Summer 2002. As of this writing it seems quite
likely that the standard will be approved after the 6 months voting
period in early 2003. Major changes to the syntax or to the maintenance
organisation of the standard are very unlikely.
RFC 2288 does not û and it was not the aim of its authors û to analyse
how ISTC-based URNs can actually be resolved. This text will specify one
solution to this question. There may be other complementary resolution
services in addition to the one described here.
Generally, the difficulty of designing a URN resolution service is
dependent on two factors:
* Is the identifier dumb, or does it provide a hint on where to find a
resolution service?
* How many potential resolution services are there?
ISBN (International Standard Book Number) is a good example of an
intelligent identifier. Analysis of the ISBN will reveal not only the
region where the ISBN has been assigned, but also the publisher of the
book. Resolution of ISBN-based URNs can be decentralised to national
bibliography databases, maintained by the national libraries. If the
ISBN were a dumb identifier, this would be impossible.
International Standard Serial Number (ISSN) is a dumb identifier. It
does not have a publisher identifier; serials published by a certain
company get seemingly random ISSNs. Although ISSNs are allocated to
regional agencies in blocks, which gives the system some "intelligence",
a resolution service should not rely on these blocks û there are just
too many of them, and their number is increasing all the time - but use
the global ISSN database. It contains a bibliographic description of
every periodical that has received an ISSN; by June 2002 the database
contained about one million bibliographic records. Thus, it is easy to
resolve ISSN-based URNs even though the identifier itself does not help
in localising the resolution service.
Like ISBN, ISTC will be an intelligent identifier (see below for a
description of its syntax). On the other hand, it will be similar to the
ISSN system in that there will be a global ISTC database, containing
every ISTC assigned in the world, and related metadata. Since ISTCs can
and will be given to textual works retrospectively, this database,
maintained by the ISTC Registration Authority, will relatively soon
become very large.
However, at least some ISTC Regional Agencies, which will take care of
ISTC assignment in their own regions (mainly geographical, but they may
also be subject-driven) will send their data in batch mode to the ISTC
register. Therefore there is a need to complement the ISTC resolution
done in the global ISTC database with regional resolution services. The
resulting system is a two-level cascade, where the bibliographic data
related to the ISTC will be available either from the global database or
from a database maintained by the Regional Agency, which assigned the
ISTC. A Regional agency may be for instance a national library, which
has generated work-related metadata and ISTCs from a traditional,
manifestation-centered national bibliography.
The registration request for acquiring a Namespace Identifier (NID)
"ISTC" for International Standard Text Work Codes has been written by
Helsinki University Library û The National Library of Finland on behalf
of the International Standardisation Organisation (ISO). The request is
included in chapter 5 of this text.
The document at hand is part of a global co-operation of the national
libraries to foster identification of electronic documents in general
and utilisation of URNs in particular. This work is co-ordinated by a
working group established by the Conference of Directors of National
Libraries (CDNL), and supported by the Conference of the European
National Librarians (CENL) Working Group on Networking Standards.
We have used the URN Namespace Identifier "ISTC" for the International
Standard Text Work Codes in examples below.
2. Identification vs. Resolution
The ISTCs identify works, that is, abstract entities, which are embodied
as physical manifestations. ISTC resolution service will only deliver a
bibliographic record related to the work or expression. In the
bibliographic record there may be links to other ISTC records describing
related works and expressions, or to manifestations of the work.
The manifestations of textual works identified by ISTCs may be printed
or electronic. In the latter case, a user may be able to retrieve all
manifestations related to the work.
3. International Standard Text Work Code
3.1 Overview
The ISO International Standard Text Work Code (ISTC) standard defines a
16 byte hexadecimal code that provides unique identification of textual
works. ISTC is as of this writing specified in the committee draft 21047,
revised in 15 May 2002. In this CD, comments given to the first committee
draft have been taken into account, and the ISTC Working Group decided to
publish the text as a Draft International Standard. Changes to the syntax
or management of the ISTC at this stage are highly unlikely.
ISTC consists of four segments, all of which are required:
- registration agency element;
- year element;
- work element;
- check digit.
ISO CD 21047 provides the following example:
ISTC 0A9 2002 12B4A105 7
When an ISTC is displayed in written form the letters ISTC shall precede
it. The segments should be separated by hyphen or space.
Registration agency element shall consist of three hexadecimal digits.
The code (in the above example, 0A9) represents the Registration agency
which assigned the ISTC.
The year element (in the example, 2002) shall consist of the four digits
representing the year in which the ISTC was allocated.
The work element shall consist of eight hexadecimal digits. The work
element shall be assigned by an ISTC Registration agency appointed by
the Registration authority for ISO 21047.
The check digit shall be calculated on a MOD 16-3 system defined in
accordance with ISO 7064.
ISTC Registration agencies must provide metadata for each work they have
identified. This metadata will be collected into the global ISTC
register maintained by the ISTC Registration authority. The data may be
updated on-line or in batch mode. Duplicates are removed from the
database with the help of a duplicate check algorithm.
According to the ISO CD 21047, ISTCs can be applied retrospectively to old
works. In such case, work metadata will be usually generated from existing
manifestation level metadata. Some projects have already analysed the
feasibility of this process with satisfactory results.
ISTC numbers are assigned by Registration agencies, which receive their
agency element codes from the Registration authority. The system allows
for 4096 such codes at any time; the codes may be re-used over time
since agencies can be identified with the combination of the agency
element and year. However, 4096 registration agency elements will be
sufficient for quite a long time (the ISSN system has about 70 regional
agencies, the ISBN system about 160).
Given the relative complexity of ISTC codes and the very large number of
textual works, which need identification, the recommended practice is to
automate the ISTC creation process. In any Registration agency the
agency element will never change, and changes in the year element are
easy to track. Work element can be used rather freely, as long as the
same identifier is never assigned twice. Since calculation of the check
digit can also be easily automated, ISTC assignment can without
difficulty be made a fully automatic process.
3.2 Encoding Considerations and Lexical Equivalence
Since ISTC consists of hexadecimal characters, there are no needs for
special encoding. However, the string ISTC preceding the identifier and
any spaces separating the ISTC elements should be replaced by hyphens
when an ISTC is used as URN.
In order to determine if two ISTCs are lexically equivalent it is
necessary to remove all spaces and hyphens from the ISTC string.
3.3 Resolution of ISTC-based URNs
An efficient and global resolution service for ISTCs can be accomplished
by using the global ISTC register. This database will, according to the
current plans of the proposed Registration authority, go into production
in January 2003. From this system, the ISTC data may be copied to one or
several systems used for public access.
An ISTC can be used as a search key for retrieving the bibliographic
record of the work from the databases containing ISTC data. This record
may contain ISTCs pointing to other works or other identifiers such as
ISBNs, DOIs or SICIs identifying manifestations (books or articles) of
the textual work.
With the help of the registration agency element and the year code it is
possible to locate the ISTC register (for instance, a traditional
national bibliography database enriched with work metadata) of the
Registration agency, which assigned the ISTC. Expanding the resolution
of the ISTC-based URNs into these databases will bring two additional
benefits. First, since the global ISTC register is maintained in batch
mode it (and databases dependent on it) may not contain the newest ISTCs
assigned by the registration authorities. Second, access to the systems
containing global ISTC data may be for fee only, while the regional
agencies may allow free access to their local ISTC registers.
Typical users of the system will be authors and publishers seeking
information about (published or non-published) works, librarians wishing
to copy catalogue metadata related to a given work, and patrons who wish
to track all manifestations of a work or expression related to it.
3.4 Additional considerations
Since the number of ISTC resolution services will eventually be high
(theoretical maximum 4096 + 1 "live" systems), encoding all services
into the URN Resolution Discovery Service, and maintaining this data,
may become a bottleneck.
The ISTC system may become very large, as it is intended to cover all
textual works, including novels, short stories and articles. Such a
system may eventually become extremely popular. It is important that
there will be multiple databases containing all or at least the most of
the ISTC metadata in existence.
4. Security Considerations
This document proposes means of encoding and using International
Standard Text Work Codes within the URN framework. This document does
not discuss resolution except at a generic level; thus questions of
secure or authenticated resolution mechanisms in the ISTC registers are
out of scope. This text does not address means of validating the
integrity or authenticating the source or provenance of URNs that
contain ISTCs. Issues regarding intellectual property rights associated
with bibliographic data related to the ISTC or other work identifiers
are also beyond the scope of this document, as are questions about
rights to the databases that might be used to construct resolvers.
5. Namespace registration
URN Namespace ID Registration for the International Standard Text Work
Code (ISTC)
Namespace ID:
ISTC
ISTC will become an established acronym for International Standard Text
Work Codes; giving this NID for any other system would cause a lot of
confusion.
Registration Information:
Version: 1
Date: 2002-07-03
Declared registrant of the namespace:
Name: International ISTC Agency / Albert Simmonds
E-mail: simmonda@oclc.org
Affiliation: OCLC Online Computer Library Center, Inc.
Address: OCLC, 6565 Frantz Road, Dublin, OH 43017-3395,
USA
Declaration of syntactic structure:
Each ISTC contains four segments:
ISTC consists of four segments, all of which are required:
- registration agency element;
- year element;
- work element;
- check digit.
When an ISTC is displayed in written form the letters ISTC shall precede
it. The segments should be separated by hyphen or space.
Registration agency element shall consist of three hexadecimal digits.
The code (in the above example, 0A9) represents the Registration agency
which assigned the ISTC.
The year element (in the example, 2002) shall consist of the four digits
representing the year in which the ISTC was allocated.
The work element shall consist of eight hexadecimal digits. The work
element shall be assigned by an ISTC Registration agency appointed by
the Registration authority for ISO 21047.
The check digit shall be calculated on a MOD 16-3 system defined in
accordance with ISO 7064.
Example:
0A9-2002-12B4A105-7
ISTC codes can be generated and parsed by computer programs.
Relevant ancillary documentation:
ISTC is an emerging ISO standard defined by ISO CD 21047 (revised 2002-
05-15). Draft International Standard version of ISTC will be published
during summer 2002, and it is expected that ISTC will be approved as ISO
standard in early 2003, after the DIS 6 months comment period. No major
changes to the syntax of the ISTC or its maintenance organisation are
likely.
Identifier uniqueness considerations:
ISTC codes will always be unique.
Two or more different ISTCs may identify the same work if multiple
registration agencies deal with the same resources, or if a single
agency deals with the same work twice. The duplicate control algorithm
in the ISTC Registration authority is intended to remove duplicates
arriving from the agencies, and any agency should have sufficient
control mechanism in place to avoid duplicate registration of works.
Identifier persistence considerations:
Once assigned, ISTC will never change. The same ISTC will not be used
again for another textual work.
Process of identifier assignment:
ISTCs will be assigned by the Registration agencies. Typically an author
or his/her agent or a publisher will apply for an ISTC. It is also
possible to generate ISTCs retrospectively for existing manifestations
(published books and articles). This process has to be controlled well
in order to avoid duplicate registration of works. One possibility is to
generate work data in national bibliographic databases, and to limit the
generation of work records to domestic works only.
The Registration authority will govern the ISTC assignment process in
the global level. The global ISTC Registry will enable duplicate control
of the identified works.
ISTC can - and should - be built via automated means.
Process for identifier resolution:
Resolution will take place as defined in chapter 3.3. The first step is
to check the ISTC register or another database containing all of ISTC
metadata, or the most of it. If there is no match, it is possible to use
the Registration agency element (and eventually the year element) as a
hint for finding the Registration agency, which has assigned the ISTC,
and the resolution service maintained by it.
ISTCs will always resolve into the work metadata. Manifestations of the
work (such as electronic versions of a book) may or may not be linked to
the ISTC metadata. ISTC metadata may also contain links to related works
and expressions.
Rules for Lexical Equivalence:
Spaces and hyphens in the ISTC string are lexically equivalent. String
"ISTC" in the beginning of the string must be neglected in the
comparison.
Conformance with URN Syntax:
ISTC consists of hexadecimal digits and it is therefore compliant to the
requirements to the URN syntax as defined in [Moats].
Validation mechanism:
Validity of an ISTC string can be checked by modulus 16-3 check digit.
Scope:
Global.
6. References
[Daigle et al.]: Daigle, L., van Gulik, D., Iannella, R. & Faltstrom,
P.: URN Namespace Definition Mechanisms, RFC2611, June 1999.
[ISO] Information and documentation û International Standard Text Code
(ISTC). ISO/CD 21047. May 2002.
[Lynch] Lynch, C., Using Existing Bibliographic Identifiers as Uniform
Resource Names, RFC 2288, February 1998
[Moats] Moats, R., URN Syntax, RFC 2141, May 1997.
7. Authors' Address
Juha Hakala
Helsinki University Library - The National Library of Finland
P.O. Box 26
FIN-00014 Helsinki University
FINLAND
E-mail: juha.hakala@helsinki.fi
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