A paper presented by Diana Dack, Consultant, at the Information Online 2001 Conference held in Sydney, Australia, 16-18 January 2001
"Persistence is a virtue" - some might take issue with this statement, but whatever your views are in relation to your personal life, I would argue that in the world of digital libraries, resources, collections - call them what you will - persistence is a virtue for some resources I am sure you can all think of some resources that could be consigned to oblivion with no great loss to mankind.
What I am talking about is persistence of access to online digital materials. Persistence of access has two aspects:-
Persistent identifiers are one tool that can play an important role in the latter.
In this paper I intend to consider briefly:
It is almost a truism that the WWW has caused a revolution in the availability and accessibility of electronic information for users of all types and has the potential to continue to effect vast changes in the way libraries, archives, publishers, etc. deliver information to their clients. Digital resources can be accessed and delivered over open networks using standard, multipurpose software already on the desktops of their clientele.
The technology and infrastructure currently available in the form of the Internet and, more specifically, the www makes possible a de facto distributed digital library, providing direct access to vast range of digital resources housed, maintained and made accessible by a variety of different institutions using widely deployed technology and open standards. Digital resources can be accessed directly by links embedded in databases, catalogues, indexes, and gateways and by links embedded in other digital objects or resources.
The success of an open distributed information system based on the www depends in the long-term on the consistency and reliability of the links which are made between documents and the links which are made in the catalogues, indexes and resource listings which provide discovery services for web based resources. These links must remain static over time.
Much of the value of online digital resources for scholarly communication lies in enabling resources to be cited reliably with actionable links over long periods of time. Libraries and archives collect for the long-term to support scholarly research and need to support access to materials beyond the life of current technology and possibly beyond the organisational structures, which exist today. They therefore have an intense interest in persistent identification of online digital resources. In this context, it is worth noting that most of the literature relating to digital library research is available only online.
You will all be familiar with the identifier predominantly used on the WWW, the URL. The URL for a resource is often simply the access protocol, the domain name of the server on which the resource is housed and its directory path and file name on that computer.
This location based nature of the URL is its major weakness as an identifier for long-term access, since the identifier will change if the material is moved either to a different server or a different place in the file structure of the same server, or if a different protocol is used. When this happens, all links to this resource embedded in other documents or databases will be broken. What is necessary to improve the reliability of links is the widespread use of well managed persistent identifiers.
A persistent identifier is a name, or identifier, for a resource that uniquely identifies that resource and will be forever associated with that resource. It will never be reassigned to any other resource and will not change regardless of where the resource is located or whatever protocol is used to access it.
Use of a well managed persistent identifier rather than a location will ensure that when a document is moved, or its ownership changes, the links to it will remain actionable.
As I stated earlier, it is essential for reliable long term access to digital resources to have persistent, unambiguous and location and protocol independent identification for online digital resources currently made available on the web. This is crucial for a number of applications:
Citation of online documents.
An increasing number of scholarly papers, research reports and significant documents and reports, including government documents, are available only online, mainly "on the web". Many more are made available in both hardcopy and online form. These digital documents often cite other online documents in the form of links to those documents. This has two implications, firstly it is necessary to unambiguously identify the item referred to, secondly there is an expectation that the link will continue to be actionable while the document is available online.
There are many examples of documents cited in lists, references in papers and resources indexed in search engine databases which can no longer be accessed at the address cited. The researcher coming across such a dead end is faced with a number of questions "Does the resource still exist?", "If it does, where is it?", and finally, "If I find something which looks like it, is it the same?"
Archiving of digital materials
Persistent identification is also an essential tool in the archiving of digital materials. There is a strong association between the issue of identification and the preservation issue in the sense that persistence of identification is essential for reliable long-term access and is one of the main reasons libraries and archives have such a strong interest in persistent identification schemes. The value of preserving material is reduced if it cannot be identified reliably, found, and accessed when cited or referenced. It is therefore important that we have functioning identification scheme(s) that leave no doubt as to the commitment to persistence implied by the use of such an identifier.
Multiple copies
There are occasions when multiple copies of a resource exist at different locations. These may be identical and they need to be identified as such. This is not possible with an identifier based on location. Examples are mirror sites and archival copies and the original work, or a resource which may be made available via a web site and an ftp server.
Rights management/access management
Rights management and access management need unambiguous identification of a resource for machine processing, hence the publishing industry and those holding intellectual property rights in online resources also have an interest in persistent identification. Because automated, commercial transactions may be involved, "industrial strength" persistent identification is critical. This is the reason the publishing industry have developed the their own identifier system, the DOI (Digital Object Identifier) - more on that later.
Catalogues, indexes and resource discovery services
Persistent identifiers are also essential for general linking in catalogues indexes and gateways. In addition to being an irritation for users trying to access material, constant change and movements of material which change the identifiers of that material can impose an unacceptable maintenance burden on the maintainers of lists, indexes, gateways or catalogues of WWW materials. Libraries and archives therefore have a keen interest in the development and implementation of permanent identifier systems that are independent of location. There is a general expectation that links in online documents and resources will "work".
XML Developers
More recently, the issue of persistent identification has become an issue for XML developers as the URI is used for identification of XML schemas and Xlinks.
Thus persistent identification of online resources is of interest to a variety of communities
William Arms sums up the importance of persistent identifiers in his article on the "Key concepts in the architecture of the digital library" in Dlib magazine
Names are a vital building block for the digital library. Names are needed to identify digital objects, to register intellectual property in digital objects, and to record changes of ownership. They are required for citations, for information retrieval, and are used for links between objects.
In spite of this interest and the fact that the issue of persistent identifiers on open networks has been discussed intensely for over 8 years, the field is still in its infancy and there is still no widely deployed resolution system other than the DNS (Domain Name System), which supports URL style identifiers. The issues to be addressed are difficult and complex and they have not yet been successfully solved by any organisation or group. There are still fundamental differences of philosophy and approach amongst the major players in the field and the standards and processes are not settled.
There are three important practical aspects to persistent identification of online resources:
General identification schemes
Persistent identifiers are not unique to the web. Many formal identifier or naming schemes are used every day by various systems, either as internal system numbers or as public identifiers. Many public identifier systems will be familiar to librarians (ISBN, ISSN, ISWC, LCCN, BICI, SICI, UPC, EAN, to name but a few) and a number of these have been discussed in the context of the naming of digital resources.
These systems have the characteristics required of persistent identifiers in the definition I gave earlier, and can be used to identify online resources. They are, however, not specifically designed, for online resources and are not yet used widely. Very few of these will be fully effective as persistent identifiers for online access and linking unless they are either registered as naming schemes and supported by a resolution system, or incorporated into another naming scheme. I will say more about this later.
It would be possible to resolve some of these to either metadata or resource via bibliographic databases, e.g. Kinetica, RLG and OCLC, but in order to do this, the request must first be routed to an appropriate host.
Identifiers designed for the Internet/web
There are a number of identifier schemes that have been developed specifically for use on the Internet and www and they are at various stages of implementation and use. I will comment on a few briefly, URN/URI, PURL, the Handle system and DOI.
Uniform Resource Identifiers (URI/URL/URN)
URLs and URNs are two broad categories of URI. The old URL specification was replaced in 1998 by RFC 2396 Uniform Resource Identifiers (URI): Generic Syntax (August 1998) which defines both the URL and URN as URI schemes as follows:
"A URI can be further classified as a locator, a name, or both. The term "Uniform Resource Locator" (URL) refers to the subset of URI that identify resources via a representation of their primary access mechanism (e.g., their network "location"), rather than identifying the resource by name or by some other attribute(s) of that resource. The term "Uniform Resource Name" (URN) refers to the subset of URI that are required to remain globally unique and persistent even when the resource ceases to exist or becomes unavailable." RFC 2396, p.2.
It is now accepted that these identifiers should be referred to as URIs, although I have deliberately used the term URL earlier in this paper. It is argued that the identifiers most people know as URLs can be names as well as locators. Although this is undoubtedly true, the fact is that most resources currently on the www are identified using a locator, i.e. are described in terms of their current locations. It is the predominantly location based use of the "http" URI that is its major weakness as a persistent identifier. It is also impossible to tell whether it is being used as a name or an address.
Uniform Resource Names (URNs)
The need for persistence in the naming of networked resources was recognised early in the life of the Internet and has been the subject of discussion for several years within the IETF (Internet Engineering Task Force), the body responsible for Internet standards.
Work on the development of a unique identifier that would be independent of location and would remain permanent even though resources might move or disappear began at the same time as work was proceeding on the formalisation of URL schemes. The identifier was named the URN (Uniform Resource Name). However there was little agreement on the details of such a scheme and consensus on the purpose and syntax of the identifier remained elusive for several years. A specification outlining the minimum requirements of the URN, RFC 1737 Functional Requirements for Uniform Resource Names by K. Sollins and L. Masinter was issued in December 1994.
This document summarised accepted basic requirements for Uniform Resource Names and by definition any useful persistent identifier scheme. These are:
"Global uniqueness: The same URN will never be assigned to two different resources.
Persistence: It is intended that the lifetime of a URN be permanent. That is, the URN will be globally unique forever, and may well be used as a reference to a resource well beyond the lifetime of the resource it identifies or of any naming authority involved in the assignment of its name.
Scalability: URNs can be assigned to any resource that might conceivably be available on the network, for hundreds of years.
Legacy support: The scheme must permit the support of existing legacy naming systems, insofar as they satisfy the other requirements described here.
Extensibility: Any scheme for URNs must permit future extensions.
Independence: It is solely the responsibility of a name issuing authority to determine the conditions under which it will issue a name.
Resolution: A URN will not impede resolution (translation into a URL, q.v.). To be more specific, for URNs that have corresponding URLs, there must be some feasible mechanism to translate a URN to a URL."
The RFC goes on to outline the necessary characteristics of a URN specification which are required to meet these requirements. The most significant was:
However, although these general principles were accepted, reaching agreement on the detailed syntax of a URN was difficult, and it was May 1997 before URN Syntax was formally agreed upon and published in RFC 2141 - URN Syntax.
It is disappointing to note that in the four years since RFC 2141 URN Syntax. was issued in May 1997, little progress has been made in the implementation of URN services and the URN appears to be no closer to widespread deployment.
It is not easy to predict how the situation relating to URNs and URIs will develop. The length of time taken to arrive at an agreed syntax for the URN reflects the lack of consensus amongst some of the major players on the need for a URN at all. This lack of consensus is still present in the IETF and W3C community, as can be seen in the relevant discussion lists.
There is a difference of philosophy between the those who regard an "industrial strength" identifier as essential and those who believe that the URL style URI could be managed to achieve the kind of persistence required. The push for a "stronger" identifier than the URL, as it is currently used, is supported by those in the digital library field who recognise that persistent naming is the cornerstone of the architecture of an open distributed library/archive system and by the publishing and rights management community who need an absolutely watertight persistent identifier system to support commercially oriented rights management and access systems. This position also is increasingly of interest to the community of xml developers who require persistent identifiers for use with xml. Those who believe the URN development to be unnecessary and misguided, argue that persistence is an administrative, social and management issue and that the URI as outlined in RFC 2396 will, if managed properly, meet all the needs of those advocating a URN standard, or any other "name style" identifiers.
For URNs to achieve widespread implementation, not only is consensus on functional requirements and syntax needed, but the ability to recognise and route URNs must be incorporated into standard Web browsers and a resolving infrastructure developed either by leveraging off the existing Domain Name System or by some other route. For this to happen, browser makers need to know what is accepted as a formal standard. However the processes and procedures for the registration of new schemes are confusing and unclear.
Internet standards in general are the function of the IETF (Internet Engineering Task Force). This body is responsible for the development of Internet protocols and standards. However in the area of WWW standards, W3C has the major role. It is responsible for Web resources and protocols for access and distribution, e.g. HTML specifications, PICS, RDF.
The URI scheme is regarded as a Web specification and its extension or modification falls within the scope of W3C activities.
W3C has to date shown little interest in URN, or "name style" identifiers.
In spite of this, the issue has continued to be debated. There is currently a W3C interest group looking at issues associated with URI schemes. The issues identified by this Group will be recommended as a workplan for a possible working group to work on and hopefully solve.
PURLs
PURLs (Persistent URLs) were developed by OCLC in the mid-1990s, primarily to reduce the maintenance burden of the URLs contained in catalogue records created for Internet resources. OCLC was an active participant in the IETF working groups on URNs and was fully aware of how far the groups were from consensus on a standard solution for persistent identification. They therefore developed PURLs as an interim solution to address the lack of progress in persistent naming for Internet resources.
Functionally, a PURL is a URL. However, instead of addressing directly the location of an Internet resource, a PURL addresses an intermediate resolution service or PURL server. This PURL Resolution Service associates the PURL with the actual URL and returns that URL to the client software. The client then completes the URL transaction to obtain the resource. The transaction is a standard Hypertext Transfer Protocol (HTTP) redirect, thus no acceptance of new protocols or modifications to client software are required.
PURLs are created and maintained using a standard Web browser to access a forms based service hosted by the relevant PURL server.
OCLC has made available the PURL source code to enable institutions to make use of the technology. Since the introduction of the PURL model and services, a number of institutions have installed their own PURL servers, including the NLA.
The Handle System
The Handle system is a distributed persistent naming system developed for digital library applications.
It was developed by CNRI (Corporation for National Research Initiatives) and had its origin in a computer science technical reports project, NCSTRL (Networked Computer Science Technical Reports Library), funded by DARPA (Defense Advanced Research Projects Agency) in the US. Part of this project was to develop an architecture for the underlying infrastructure of an open distributed digital library. The high level architecture developed by the project is described in a seminal paper A framework for distributed digital object services May, 1995 by Robert Kahn and Robert Wilensky and subsequently by William Arms in an article Key Concepts in the Architecture of the Digital Library in D-Lib Magazine, July 1995.
The Handle system is implemented by the Library of Congress in its National Digital Library Program, and in the US Copyright Office (CORDS) where handles are assigned to deposited digital objects. The Handle system is also used by the DOI system for resolution of DOIs and in the US Defense Technical Information Center.
The handle system is more than a simple naming scheme, it is supported by a resolution system consisting of a distributed system of global, local, and caching servers. This is one reason why it was chosen by the IDF (International DOI Foundation) for the DOI.
A Global Handle Registry run by CNRI registers the top level naming authorities, both to ensure the uniqueness of the names and to route requests for handle resolution. Local handle services which are run by organisations and individuals resolve the requests routed to them and return the current address(es) or other information about the resource sought.
The handle system provides all the capabilities listed in RFC 1737, "Functional Requirements for Uniform Resource Names" described earlier.
The Handle software is made publicly available and can be downloaded from the CNRI Handle site.
In the absence of ubiquitous support for the Handle protocols in standard browsers, both LC and DOI use http proxy servers to enable standard browsers to access handles.
For a more detailed and technical description of the system see The Handle System, Version 3.0 An Overview <http://www.handle.net/docs/overview.html>
Digital Object Identifier (DOI)
The DOI was developed by the AAP (American Association of Publishers) as a response to the growing concern over rights protection in open electronic networks. It was officially launched at the Frankfurt Book fair in 1997 and it has recently been registered as an American National Standard ANSI/NISO Z39.84-2000.
The intention was to develop an industry wide, standard identifier that would be assigned to a work or manifestation of a work at the time of creation. Its development was seen as a first step in the development of rights management infrastructure in the digital environment. The identifier is intended to support systems to control transactions, provide a key for rights management systems and facilitate communication between publishers and their clients.
In order to achieve this, the DOI has been developed as a complete system. It consists of three components:
A record of the DOI together with a brief metadata record and the current location of the object is registered in the DOI system server. This server acts as a resolver to the objects themselves, which continue to reside on the publishers site or on a site licensed by the publisher. Changes of location are registered with the central server.
DOIs are resolvable through a native handle server for those with a handle enabled browser or via a proxy server to resolve to the handle server for those with standard browsers.
DOI Metadata
The metadata is an important component of the DOI system:
To support these processes, registration of a minimum set of standard metadata with the item is required.
For this purpose, the DOI has adopted the INDECS (Interoperability of Data in E-Commerce Systems) metadata set. The INDECS project, designed to provide a common metadata framework to support E-commerce in intellectual property, meshes neatly with the requirements of DOI. Eight mandatory elements are prescribed in the minimum, or kernel set of metadata, three of which (Genre, Type and origination) are to be derived from standard lists.
DOI governance
The development of the DOI system has been the responsibility of the International DOI Foundation (IDF). The IDF is a not for profit organisation founded by the AAP, and its members are drawn from major publishers and software companies, as well as organisations which represent the interests of publishers and rights holders. E.g. International Publishers Association, International Association of Scientific, Technical and Medical Publishers, Authors Licensing and Collecting Society (ALCS), CSIRO Publishing, Copyright Clearance Centre, JISC, OCLC, and The Open University.
The DOI system is run on a cost recovery basis. It is an open system, free at the point of use and anyone may use a DOI to link to services. The DOI can be integrated into local environments and databases without charge. The cost of assigning a DOI is borne by the publisher or rights holder when it is assigned. The development costs have to date been borne by IDF membership fees.
The governance, administrative structure and charging mechanisms are undergoing change at present and in future management of DOI service will be delegated to registration agencies. These agencies will have a certain amount of freedom in the way they allocate resources and charge for them.
Future developments for DOI of interest to libraries and archives
The DOI is a well thought through and well-designed system, and it remains to be seen whether it is successful.
Many of the considerations of persistence and identification of electronic resources facing DOI are those facing libraries and archives, even though the latter are not operating in the full commercial paradigm.
There has been considerable discussion and concern expressed in many quarters about the direct relationship of the DOI with rights management and copyright considerations. It is seen by many as satisfying needs of major publishers while not necessarily meeting the needs of rights holders and those interested in "fair use".
The majority of online publishers are not in the same league as the major publishers and there are fears that the system may not be affordable for them. In addition to the charges associated with membership and the payments to registration agencies for the purchase of prefixes and assignment of identifiers, they may see participation and maintenance of the system, or the stringent requirements for the provision of metadata as a barrier.
Amongst some libraries and academic institutions, there is the concern that the rights management aspect may have the effect of making it easier to close off materials by making them unaffordable.
All the identifier systems I have just described follow a similar pattern consisting of two parts, the name of a naming authority which is registered as globally unique, and a local identifier which must be unique to the naming authority, but may take any form. This pattern meets the necessary characteristics of a URN specification outlined in RFC 1737 which I mentioned earlier. The patterns of the identifier schemes are as follows:
|
URI |
most common pattern used is <scheme>://<authority>/<path>e.g. http://www.nla.gov.au/somewhere/something.html ftp://www.nla.gov.au/wherever/whatever.txt http://purl.oclc.org/maint/register.html |
|
URN |
urn:<Namespace Identifier>:<Namespace Specific String> |
|
DOI |
<Directory code.Registrant code>/<DOI Suffix String> |
|
Handle |
<Naming Authority>/<Name> |
This gives maximum flexibility in the identification of resources whilst at the same time creating standard identifiers to support interoperability. Global uniqueness is guaranteed by including a form of unique name or identifier for the naming authority to supply that uniqueness and allowing almost any form of identifier to be used locally.
Organisations may therefore use any identifier scheme which meet their internal needs. (E.g. local system numbers, standard numbers, schemes developed for specific kinds of materials, dumb numbers or "intelligent"). The issue for an organisation or individual wishing to adopt a system of persistent identifiers for their resources will be what else is required of that system and what other needs of the organisation it is intended to serve. Whatever scheme you use locally can be fitted into a global or national scheme of this type.
I have mentioned several times, in passing, the term resolution. Resolution is the process that interprets an identifier and locates the resource. A fully operational global system of protocol independent persistent identifiers requires an open and fully deployed resolution system such as that which underpins the www. In the discussions on URN, there is general agreement that there is a need to distinguish between naming schemes and resolution systems. A persistent identifier scheme should not be tied to any specific resolution system and must of necessity be capable of outlasting any systems and protocols that are currently in use. However it does need some form of resolution system to be effective, and the lack of a widely deployed resolution system for name type identifiers is a major obstacle to the wide deployment of URNs.
In the context of the www, the process of resolution requires two components
At present, neither of these is in place.
There is currently no protocol independent resolution scheme available which will resolve, or map "name style" identifiers such as the URN to the location of the resources. The importance of resolution cannot be overestimated. The strength of the existing URL standard, which supports most of the information on the www, is a widely deployed resolution system in the form of the DNS (Domain Name System). This is the system which maps the domain name of the URL request to the IP address of a server and enables the routing of the request to the appropriate place to service the request. There is no equivalent system for non-URL schemes, although there are people within the IETF working on approaches to resolving name type schemes leveraging off the DNS. These approaches still at the draft stage, however, and are not yet accepted standards. Those of you who are interested may wish to look at the Internet drafts relating to NAPTR and DDDS.
The original idea was that URN would work through a resolver discovery service (RDS) - requests routed to a server which could identify which servers were registered as being able to resolve a particular namespace.
I mentioned also the need for standard browser recognition of the identifier. Some schemes have built-in resolution systems. The Handle system and DOI, which is an implementation of the Handle system, are examples of such schemes. However the benefit of their resolution system is lost if they cannot take advantage of the standard www browsers used by most of their target audience. Handles can be used with a browser plug-in, but many users are still reluctant to download and install a plug-in.
What is necessary before recognition and routing of name type URIs is incorporated into standard browsers is a formal recognition process for URI standards so that browser makers can know what is formally accepted as a standard.
There is little prospect of an early solution to the resolution issue. All URN and other persistent identifier systems implemented in the near to medium future will require proxy servers to enable them to be used by standard web browsers This means that the identifiers will have to be encapsulated in a URL using the proxy server address.
Until the issues of browser recognition and resolution are addressed, proxy servers will be required for most persistent identifier systems, thus the identifiers will not be truly protocol independent until http proxy server no longer needed.
Persistent identifier schemes and supporting infrastructures are essential tools to support persistent access to resources but are only one part of the solution. Good management and administrative structures are also an essential requisite There is a need to manage namespaces, to manage the resources online and to maintain the association of the persistent identifier with the current location of the resource. There is nothing magic about a persistent identifier which makes information management redundant - it is simply a tool which can make the process more efficient. There is a strong analogy with a library catalogue or stack directory - you can have a wonderful catalogue, but if you move the material around and don't update the location information in the catalogue or stack directory, you will soon "lose" much of your material.
NLA has had a long-standing interest in persistent identifiers. It is seen as an important element in an open distributed digital archive.
The Library is looking to offer assistance in the development of a national system. The preferred model is a distributed one in which NLA might take responsibility for managing the naming system and registering participating organisations as naming authorities and possibly establishing a resolving service. Participating organisations would become naming authorities and assign and resolve their identifiers locally. There would however be wide consultation before such a step was taken.
It is not an easy issue as you will appreciate from my earlier comments. There is no obvious best way of doing this at the present time. Options range from managing URLs better to a fully fledged system.
The Library implemented a PURL server in 1998 as an interim measure, but there was little uptake. Perhaps because it was too closely linked to archival preservation in the publicity, perhaps it was too soon, perhaps it was because the PURL had "nla" in the name it is not clear. One option is that the Library may consider revamping the PURL service, if only as an interim measure.
The Conference of Directors of National Libraries has had a persistent identifier working group considering what national libraries can do to foster the use of persistent identifiers amongst libraries and archives and to look at avenues of co-operation. At the instigation of the National Library of Finland, the Group endorsed in principle a URN namespace "NBN" (National Bibliography Number) which would be a potential vehicle for a common URN based identifier for national libraries.
The NBN as originally conceived by the National Library of Finland was simply an electronic National Bibliography Number, and was essentially a running number assigned to a single digital resource. The specification was subsequently further developed to accommodate a variety of needs and at the time of registration as an NBN namespace it was defined much more broadly, although still in terms of a national bibliography.
There is no resolution system defined for the NBN. It is suggested in the Registration document that resolution would be through national bibliographic databases, or through web indexes or archives.
As a URN, use of the NBN will be dependant on the widespread deployment of resolution systems for URN, and in the foreseeable future will require proxy servers to resolve.
Some of the European libraries are using NBN to name their archived items, but these are only resolvable locally and are not "actionable" in the sense I have been discussing.
In-2000, the NLA decided to review the current options which are available for a persistent identifier system and engaged a part time project officer to focus on the issues associated with persistent identification systems for digital resources.
The aim is to assess the options available for implementation of a persistent identifier system and ways in which to engage owners of digital resources in the task of maintaining persistence of access by means of actionable links. This involves:
One other outcome of the project will be a bibliography on persistent identification to be published on PADI
As part of this process, the Library is testing the Handles system.
As mentioned earlier, the Handle system is a distributed persistent naming system developed for digital library applications by CNRI and is used by the Library of Congress in its National Digital Library Program, by the DOI system and in the US Defense Technical Information Center.
To fully evaluate the use of the Handles system or DOI as an option, the Library needs to be able to assess the level of complexity involved in the installation and use of the system. The system has fully fledged management, security, registration and resolution capabilities, it is therefore not a simple system. The Library was not in a position to make a factually based assessment of the feasibility of running a handles based system without a clearer idea of the functionality, the robustness and resource requirements of the Handles software. The NLA has installed the system and is in the process of evaluating it. (January 2001)
The aim of the test is to evaluate
After initial teething problems relating to authentication because of an old version of the software, we believe the system may be relatively straightforward.
The Library is also a member of the W3C interest group established to look at issues associated with URIs and therefore URNs. We are hoping to see the issues of resolution of "name type" identifiers, standards registration and browser recognition carried forward to a Working Group agenda.
The library is looking to at ways of encourage libraries and others to manage their information to maintain persistence of access for the long-term. A number of guidelines to help users achieve this are being issued. The first of these, Safeguarding Australias Web resources guidelines for creators and publishers (www.nla.gov.au/guidelines/2000/webresources.html) has been published this week, and a companion document on Managing web resources for persistent access (www.nla.gov.au/guidelines/2000/persistence.html) will be issued as a companion brochure soon. (Issued March 2001)
Much of the information management practices outlined in the brochures is a prerequisite for the effective use of persistent identifiers. It is certainly possible, in the absence of URN or "name style" identifiers to manage URLs better. They can be managed with a resolver database, with redirects, with PURLs, and this can be done now. The organisation and discipline required to do this is a prerequisite for implementing any other system at a later time.
The NLA is hoping to work with libraries and other organisations such as Australian Archives to look at the issue of persistent access for significant Australian materials, including government information.
We want to encourage you as librarians and information managers to lobby for good information management and use of persistent identifier systems in your organisation where appropriate. Librarians and information managers have an investment in the continued access to online resources. Many website developers and hosting services are very good technicians and are very skilled at what they do, but they are often not information managers with a long term view and an investment in the content of the site. You can provide that.
What we are attempting to do is to foster an attitude of looking at online resources with an eye to persistence and promote the principle that "Persistence is a virtue".
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