Collection Level Description
A review of existing practice
An eLib supporting study

Editor	Andy Powell, UKOLN, University of Bath	
Email	a.powell@ukoln.ac.uk 	
Other authors	Rob Bull (CrossNet Ltd), Martin Fisk (Aurora Information Technology), Martin Hamilton (Loughborough University), Brian Kelly (UKOLN), Ray Lester (Natural History Museum), Ann Matheson (National Library of Scotland), Patricia Methven (King’s College London), Jim Murray (National Library of Scotland), Dennis Nicholoson (Strathclyde University), Rosemary Russell (UKOLN) 	
Keywords	Library; EAD; Encoded Archival Description; Archives; ISAD(G); General International Standard Archival Description; Dublin Core; Conspectus; Museums; WHOIS++; ROADS; Collection Level Description; Z39.50 Explain; LDAP; X.500; Centroids; Z39.50 Profile for Access to Digital Collections; GILS; Internet; Web; WWW; Collection Description; WASRV; Service Description; ISO 2146; Web Collections; 	
Abstract	A review of existing practice for collection level description, as it exists in the library, archival, museum and Internet communities. 	
Date	August 1999 	
URL	http://www.ukoln.ac.uk/metadata/cld/study/	
1	
Contents
Abstract	3
1	Introduction	3
2	What is a collection?	5
2.1	A Library Perspective	5
2.2	An Archival Perspective	6
2.3	A Museum Perspective	8
2.4	An Internet / Web perspective	9
3	Collection Description	11
3.1	Conspectus	11
3.2	ISO 2146	19
3.3	Z39.50 Profile for Access to Digital Collections	23
3.4	ISAD(G) - General International Standard Archival Description	23
3.5	EAD - Encoded Archival Description	26
3.6	Other archival approaches	27
3.7	GILS	28
3.8	WHOIS++ / ROADS	29
3.9	Centroids	31
3.10	Dublin Core	34
3.11	Web Collections	35
4	Service Description	39
4.1	LDAP / X.500	39
4.2	WASRV	39
4.3	WHOIS++ / ROADS	40
4.4	Z39.50 Explain	42
References	43
Acknowledgements	45

Abstract
This study reviews existing practice for providing collection level descriptions, as it exists in the library, archival, museum and Internet communities. It begins by providing a discussion on what the term ‘collection’ means, firstly from the perspective of libraries, museums and archives and then taking a look at the more recent meaning of the term as it is used on the World Wide Web. Finally, a detailed look is taken at some of the existing schemes that are used for collection and service description.
This study was written over a fairly long period of time (1998/99), using contributions from a number of different authors.  It was initially published on the Web in August 1999.  It is therefore worth noting that some of the references in this study to events that will happen in the future may now have taken place.
1	Introduction
This study reviews existing practice for providing collection level descriptions, as it exists in the library, archival, museum and Internet communities.  It originated from discussions at MODELS workshops [MODELS], where the need for a review of different approaches to collection level description was identified, particularly in the context of phase 3 of the Electronic Libraries Programme [ELIB]. The study was taken forward by UKOLN as a MODELS recommendation.
At the simplest level one can think of a ‘collection’ as being any aggregation of individual ‘items’ (also known as ‘objects’ or ‘resources’). Items may be physical or digital. Physical items include books, journals, museum artefacts, photographs, papers, etc. Digital items include Web pages, databases, images, etc. In some cases the digital items are surrogates of physical items, in others the digital items are the primary (only) manifestation of the item. Some collections are catalogues (metadata) for other collections. For example, a library catalogue, which is itself a collection, typically describes the items in one or more collections within a library. Collections may be grouped by type, by subject area, by geographic location of resources or according to some other criteria. Collections may be permanent or transient. Collections of Web resources may only exist long enough to transfer information about the collection from one application to another.
Section 2 of this study provides a more detailed discussion on what the term ‘collection’ means, firstly from the perspective of libraries, archives and museums and then taking a look at the more recent meaning of the term as it is used on the World Wide Web.
This study uses the following terminology: 
Collection 
An aggregation of resources. Collections are exemplified by the following non-exhaustive list: Internet catalogues (e.g. Yahoo); subject gateways (e.g. SOSIG, OMNI, ADAM, EEVL, etc.); library, museum and archival catalogues; Web indexes (e.g. Alta Vista); collections of text, images, sounds, datasets, software, other material or combinations of these (this includes databases, CD-ROMs and collections of Web resources); collections of events (e.g. a lecture series); library and museum collections; archives. A variety of mechanisms for providing collection level descriptions are described in section 3 of this study. 
Item 
An individual object, for example a Web page, an image file, an audio file, or a movie. Items are often referred to as resources, objects, documents or document like objects (DLO). The dividing line between collections and items is somewhat vague because items may themselves be collections of other objects. For example, a Web page may be a collection of text, images, applets, etc. However, because the component parts are intended to be rendered together as a whole, a Web page is typically treated as an item rather than a collection. Description of individual objects is well established within the curatorial traditions. Consider, for example, the MARC records used in libraries to describe books and journals. On the Internet, resource description is less well established but a variety of mechanisms either have been or are being developed, including GILS [GILS] and the Dublin Core [DC]. These mechanisms for resource description are only described in detail in this study insofar as they may be used to provide collection level descriptions. 
Service 
An application level service and associated protocol. Services provide the mechanism for end-users or, in the case of digital resources, end-user’s client software, to gain access to collections and their component items. Services may be physical, a library or museum service, or digital, a Z39.50 server. Access to digital services is typically based on the client-server model currently, though we are likely to see a move towards distributed object models in the future. Digital service descriptions typically provide the client with enough information to connect to the server. The information they contain is dependent on the particular protocol in use but is often as simple as a machine name, a port and a database name. Section 4 of this report considers a variety of mechanisms that have been, or currently are being, developed to describe application level services. 
Service Provider 
An organisation or individual who manages and provides access to resources or collections of resources. Describing organisations and individuals is well understood and a variety of mechanisms for providing directories, often called ‘white-pages services’, have been developed, both within ISO (X.500 [X500]) and by the Internet community (LDAP [LDAP], WHOIS++ [RFC1835]). This report does not discuss service provider description in any detail. 
Andy Powell, UKOLN
2	
What is a collection?
This section provides a more detailed discussion on what the term ‘collection’ means, firstly from the perspective of libraries, museums and archives and then taking a look at the more recent meaning of the term as it is used on the World Wide Web. 
2.1	A Library Perspective
Harrod’s librarians’ glossary (8th ed. London, 1995) gives the following definition of a library collection:
A number of books or other items on one subject, or of one kind, or collected by one person or organisation.
Also given is a definition of a special collection:
A collection of books connected with local history, celebrities, industries, etc, or on a certain subject or period, or gathered for some particular reason, in a library which is general in character. The following paragraphs attempt to elaborate on the different types of library collections. It should be noted that there is overlap between the various categories.
Subject collections 
There are several types of subject collections: 
1.	A complete library: a special library is an example of a subject collection which is a complete library, e.g. the Advocates Library, St Bride Printing Library, where the vast majority of library materials will be on a single subject. These types of collections will normally be developed by the acquisition of new materials on the same subject. 
2.	A subject collection within a library: a collection of material on a particular subject kept together within a larger general collection, and usually with a distinct name, e.g. the Graham Brown Collection in the National Library of Scotland - a collection of some 20,000 items of Alpine and mountaineering literature; and the Warden Collection consisting of around 4,600 printed items comprising books, pamphlets and runs of periodicals on shorthand, and including some texts reproduced in shorthand. These types of collections will either be added to, as in the case of the Graham Brown collection, by the availability of funding to supplement the original collection, or a ‘dead’ collection as in the case of the Warden Collection, where no material is added. 
3.	A dispersed collection within a library: a collection of material on a single subject, but not kept together and not referred to by a specific name. A university library, for example, will normally have a 20th-century English literature collection, but the monographs and serials might well be shelved in different areas of the library building; any relevant manuscript material will almost certainly be stored elsewhere. In the case of closed access libraries, such as the National Library of Scotland, collections may be arranged by some other facet than subject. The basic arrangement in NLS is by size within very broad subject groups (humanities, science, fiction, etc.); the NLS collection of 20th-century English literature is therefore completely dispersed throughout all its collections; access has to be through catalogues and guides.
4.	A collection may also be kept together because of its important association rather than, or in addition to, the subject matter itself. The Newhailes Library Collection in NLS, for example, is a large part of the library of the Dalrymple family, formed mainly by Sir David Dalrymple (1726-92), Lord Hailes, and is the most important contemporary collection to survive from the period of the Scottish Enlightenment and reflects the interests and achievements of a central figure in 18th-century Scottish history. 
Form collections 
A collection of library materials can be shelved by form, rather than by subject. It is common for serials to be shelved in a separate sequence. It is also normal for non-print material to be shelved away from printed material, so that material such as tapes, videos, CD-ROMs and microforms form separate collections in many libraries. It is also common for collections of government or official publications collections to be stored by form, or origin, of publication, as this is usually more helpful to users of the collections. 
User collections 
Some specialised collections can be arranged specifically for a particular group of users. The collections of the National Library for the Blind will contain material on many subjects and in more than one form, but the common factor is the needs of the users - the blind and partially sighted. 
Database collections 
Access to a collection of online databases, or to a collection of networked CD-ROMs, is another type of collection. These collections will normally be linked by subject, as well as by form. 
Distributed collections 
A collection may also be distributed, i.e. shared among several libraries. Australian libraries operate a Distributed National Collection, defined as: 
The aggregation of all collections in Australia which are recorded in generally accessible databases and are accessible, either in person or via inter-library loan, to users with bona fide reasons for access;
and
comprehensive in relation to Australiana and selective in relation to the rest of the world as present and future needs of Australia require.
The Research Collections Online project being developed by the Scottish Confederation of Research Libraries (SCURL) contains examples of cases where an individual library may not have a research level collection in a given subject, but where a group of two or three libraries with collections just below research level can collectively provide a distributed research level collection.
Virtual collections 
A recent development is that of the virtual or digital collection, where a selection of material on a particular subject is made available online. An interesting example is the ‘Studies in Scarlet’ project, co-ordinated by the Research Libraries Group (RLG), where research material on marriage and sexuality in the United States and the United Kingdom, 1815-1914 is being brought together and made available digitally. The core material is being contributed by the Harvard University Law Library, the University of Leeds Library and the New York Public Library, with details of supporting case studies supplied by another four United States libraries and archives. Interestingly, the material in this digital collection started life as a distributed collection. 
Jim Murray, National Library of Scotland
2.2	An Archival Perspective
2.2.1	Archives
Until comparatively recently most archivists would have dismissed the idea that an archive could be described as a collection at all. In archival theory and practice an archive is a whole which documents the life and work of an institution or individual, which has been retained in its original working order and is of known provenance. As such it may include every form of document, minutes, case-notes, memoranda, files, report books, plans, deeds, patents, letters, diaries, contracts etc., in hard copy (manuscript, typescript or printed) or electronic form; all types of audio-visual materials; printed books, where they form an integral part of the record of the institution as individual; and even objects where again they may form an integral part of the record. The latter may range from reference samples of manufactured glass through to a poem written on the headband of a hat by a leading poet. Internationally this whole is commonly described as a fonds.
Catalogues to archives are generally arranged hierarchically and commonly stop short of item level descriptions. To avoid duplicating information at a number of levels, contextual information is pushed as far up the hierarchy of description as possible. A clear description of this procedure is offered in the International Council on Archives standard, ISAD(G): General International Standard Archival Description (1993) [ISADG], and also the Manual of Archival Description compiled by Michael Cook and Margaret Proctor.
2.2.2	Collections
In contrast to archives, the term collection has tended to be used, again until comparatively recently, to describe groups of items, sometimes of linked interest, typically compiled by an individual and as likely to lodged in a library as an archive repository. In libraries such collections are sometimes managed in comparable ways to special collections of printed books or rare books and catalogued item by item. In archival repositories (which may or may not form part of libraries) they may be referred to as artificial collections and are catalogued at a variety of levels depending on the particular interest of the material and the ease with which the information can be conveyed to the potential user. Disparate collections, per item, take longer to catalogue than coherent archives. As a research resource such collections are not invariably regarded as reliable, in terms of authenticity and date, or as rich a source of information as a whole archive because they often lack related contextual information about why records were compiled and how used by their creators. Such collections may be further impoverished if standard library practices are used in cataloguing and the interrelationship of items is disregarded.
Because of the need for a distinguishing terminology, and in the context of wide-ranging discussion of providing networked access to catalogues, the concept of a collection level description has become commonly used in recent years to refer to the highest level of description of both individual archives or collections. In terms of ISAD(G) this generally means fonds level, the level at which an archive as a whole may be described. Minimum conformity to ISAD(G) includes a reference code, which includes country and repository codes, and repository specific catalogue codes and numbers; dates of creation of the archives; title of archive; extent and a statement of the level at which the holding is described. Both the National Council on Archives Networking Policy Committee, and the Scottish Record Office, in its SCAN project to provide a networked access to Scottish archives, recognise this minimum as an acceptable basis for fonds/collection level description and therefore participation in a national network. This conclusion, however, is born of a desire to promote maximum networked access to holdings in the near future and a recognition of the scale of the challenge faced by number of repositories, particularly those external to the Higher Education sector, rather than a recognition of the adequacy of this number of elements. It is indicative, in Scotland, that the title element is expanded to include some brief administrative or biographical information. It is also the case that many archivists would wish to see several more of the 26 elements of ISAD(G) included in a minimum specification than the authors of ISAD(G) suggested.
ISAD(G) rules may generally be applied without difficulty to artificial collections, especially since their hierarchies are either non-existent or extremely simple. There is, however, some discomfort about this approach among curators of large numbers of older very small manuscript collections (sometimes single volumes), many of which have an individual provenance, and which might arguably be treated as individual collections in their own right. Precisely because they are not proper fonds and may be literally one item. Experiments in the National Library of Scotland suggest that it may be possible to impose retrospective collection status on groups of themed or chronologically linked items for purposes of network presentation but if this was to extend to imposition of some form of provenance it is unlikely that it would gain widespread acceptance within the archival community.
2.2.3	Guides to holdings
Because of the size and complexity of the catalogues to many archives, repositories prepare guides to holdings. This is understood as good practice with regard to outreach and the preparation of good quality attractive published guides has been encouraged through competition by the Society of Archivists. The function of a guide is to provide a brief introduction to holdings, sufficient for the average reader to decide whether it is worth inspecting detailed catalogues further.
An individual entry describing an archive or collection may or may not equate to a collection level description depending on the level of detail included. Minimum ISAD(G) is sufficient only to identify and locate a fond or collection. An entry the equivalent to a published guide will normally include a wider range of elements which cover scope and content, administrative and biographical background and terms of access to the original material.
Patricia Methven, King’s College London
2.3	A Museum Perspective
In this context, it is perhaps most useful initially to contrast the different types of physical artefact handled by ‘archives’, ‘museums’, and ‘libraries’. In an archive we have, say, the hand-written letter; in a museum, say, an example of a Chippendale chair; in a library, say, a copy of a published book. (There are also, of course, ‘galleries’, with an individual gallery containing, say, a particular painting by Sisley. Galleries do not seem to this writer to raise significant issues beyond those below; but it is worth commenting that at the level of the individual artefact they have more in common with archives, than with their more usual bedfellows, museums.)
All physical artefacts are axiomatically unique objects. But whereas the physical stuff of archives is, or is generally organised to be, absolutely unique, that of libraries has for virtually all library users a uniqueness which is of no interest at all. Unless, that is, the library document has a rarity which then makes it almost, or indeed absolutely, unique. Thus the common practice of combining the management of ‘archives’ and ‘rare books’ collections within libraries. Subject to that proviso, since it is the ‘content’ of books and other published documents, rather than their physicality, that is the only interest to virtually all of us; since, also, that content speaks for itself - it does not have to be ‘described’ for it to be understood; and since, further, the process of publishing - by definition - results in multiple copies (the more the merrier): all this means that electronic publishing and digitisation and the resulting ‘virtual’ library collections can be conceptualised as a complete and totally acceptable substitute for print publishing, and print document shelving, and ‘real’ library collections.
Not so, ‘virtual’ museum collections: or, at least, not in the same way. A prime reason that people travel to visit museums is to see the actual physical objects (or ‘faithful’ replicas of the originals of such objects) contained therein: because by doing so they have richer experiences than they would have by reading about the objects - or, indeed, by viewing three-dimensional digital representations of those objects. But, of course, it is more than that. All museums these days within their public galleries provide explanations of the significance of the objects they display: increasingly, these explanations are electronically produced and provided explanations. The explanations frequently act as a link between the object displayed and the ‘collection’ of which that object is a representative. In the same way, all museums behind the scenes are creating catalogues and visual representations of their objects as aids to scholarly research: again, placing the objects in the context of the collection of which they are components.
But how, then, are such museum collections delineated? Almost always, the collections of ‘archives’ delineate themselves: they relate normally to a specific person or institution. The collections of ‘libraries’, on the other hand, should be delineated by the purpose for which the library exists: by the information needs of their user populations. In contrast, the collections of ‘museums’, are - again - delineated somewhere between those two extremes. They can perhaps best be conceived as a bridge between the collecting desires and interests of specific people or institutions; and the information needs - in the widest sense - of those who might use the resulting collections. Inevitably, in choosing what to collect, and what not, there is a significant tension between the collectors’ wish to be comprehensive in coverage of the chosen domain; as against the need to ensure the (future) usefulness of the resulting collection - especially in the context of the resources needed to create and maintain it.
‘Usefulness’ to whom? It is not just that museums nowadays feel the need to make their collections of physical objects more ‘intelligible’ to those who would peruse them. It is also that the very relationship between museums and their public is being radically changed so that it is the public - rather than as originally when the idea of museums were first promoted, the museum itself - that is in the superior position. To quote from a recent article: early in the next century it is anticipated that
the Museum’s role will have been transformed from one of mastery to one of service
Further, there will then be:
...a reservoir of possibilities. From that very rich reservoir, it will be the public - voting with its feet, voting with its credit cards, and acting through its elected representatives - which will determine of those many possibilities the combinations best meeting its needs and wants.
It is then that we can conceptualise using our developing global electronic networks to provide ‘the public’ with virtual entrees to the best of the physical artefact collections: lenses which focus on representations of subsets of those leading collections. The future collection policy of the museums holding such collections is then increasingly determined not by the responsiveness of the people who visit the museums in person; but by those who visit the museums virtually. In my conception, use of digital artefacts does not ultimately substitute for interaction with the real museum artefacts themselves: in the way that it certainly can for library artefacts, and can also much of the time for archive artefacts. But such digital museum artefact use fundamentally influences what the user perceives to be worth preserving for real, and for what purposes.
Ray Lester, Natural History Museum
2.4	An Internet / Web perspective
What is a ‘collection’ on the Web? The World Wide Web Consortium (W3C) currently define a ‘Web Collection’ as: 
A portion or section of a Web site, consisting of two or more Web pages, that represents a non-trivial, self-contained resource, but is still maintained by the same publisher of the overall Web site. 
Examples: Web journal, electronic monograph, photo gallery ... 
[W3CTERM]
This definition is somewhat restrictive. In the general case, a collection of Web resources may encompass material from more than one publisher. We can define two broad classes of Web collections:
1.	collections of items that are accessible using the Web 
2.	Web-accessible collections of information (metadata) about collections of items that are accessible using the Web 
The first includes complete Web-sites (for example a university or corporate Web-site), selected parts of such sites (for example a departmental Web-site) and smaller collections of items (such as all the Web pages that make up a document). These examples of collections typically have a long lifetime. Others may not. For example, consider the collection of stories that make up a particular news bulletin made available across the Web.
The second includes manually created catalogues of Internet resources, often referred to as ‘subject services’, ‘subject based information gateways’ or, more recently, ‘portals’. It also includes robot-generated databases of Web pages, often referred to as ‘Web indexes’ or ‘Web search engines’.
Individual resources on the Web today have little structural relationship with each other. Resources may be linked, but there is no way of knowing the relationship between the resources. One well-known limitation is the inability to easily print a document that has been split into multiple linked HTML pages. Any general-purpose utility that attempts to automatically create a single document for printing is liable to fail by following arbitrary links from the resource. Another limitation is the inability to provide a richer mechanism for browsing. For example PowerPoint users will be familiar with linking to next and previous slides in a variety of ways (pressing the space bar, left or right mouse button, left or right arrows, N or P keys, etc.) This is not easily possible with simple HTML resources. A third example is the difficulty of grouping resources on a Web server for processing in different ways. For example, it is difficult to specify that an indexing robot should not retrieve a group of resources, or that an off-line browser can download a group of resources. It may be possible to make use of the underlying directory structure to carry out such tasks, but this is not a general purpose, or in many cases, scalable solution.
There have been various attempts to provide a way of describing collections of items on the Web including ‘Web Collections’, ‘Channel Definition Format (CDF)’, ‘Meta Content Framework (MCF)’ and more general site maps. These are described in more detail in the Web Collections section of this study. However, none of these approaches have been adopted on a widespread basis. 
Andy Powell, UKOLN
3	
Collection Description
3.1	Conspectus
3.1.1	Origins
The Conspectus methodology originated with the Research Libraries Group (RLG) in the United States in 1979, and was adopted by the Association of Research Libraries (ARL) in the early 1980s, as a means of providing a map of library collections and collecting policies with individual libraries or among a group of libraries. It was also adopted in Canada where the National Library of Canada organised a number of regional Conspectus projects. In 1984 the British Library began a Conspectus survey within its own collections, and the results were published in 1986. Conspectus methodology was also applied among Australian research libraries. Scotland decided to use Conspectus in a group project in 1985, and this was the first group use of the methodology in Europe. It was then adopted in the Netherlands, based very much on the Scottish model of use. It has also been used to a more limited extent by some libraries in other parts of Europe (e.g. Sweden, Italy and Spain).
3.1.2	Aims
The original aim of the methodology was to try to find a mechanism that would enable librarians to ‘measure’ the strengths and weaknesses of their collections. There was a dual aim of identifying strengths and pinpointing weaknesses, so that the strengths and weaknesses of collections could be viewed not only within the framework of an individual library but among a group of libraries or across a region or a country. The primary purpose was to assist co-operation among libraries so that limited resources could be used more effectively to maintain services to researchers. Even then it was clear that the resources available to libraries to build collections and maintain services were under pressure, and likely to continue to be so for the foreseeable future. At its inception there was also a general view that if this could work to assist libraries to share resources for collection building and maintenance, then it might also be capable of use for sharing preservation responsibilities, and that there might also be other potential resource-sharing applications.
3.1.3	Methodology
The original Conspectus methodology provided a subject framework, issued in the form of worksheets, of 25 Divisions based on the Library of Congress classification system (e.g. Art and Architecture, Economics and Sociology, Medical and Health Sciences). These Subject Divisions were further sub-divided into about 250 categories (e.g. Architecture, Sculpture, Painting etc. within the Division of Art and Architecture); each category was then sub-divided into individual subject lines (e.g. Ancient, Mediaeval, Renaissance. Baroque etc. within the category of Architecture), against which the Conspectus level indicator was applied. There are around 7,000 subject lines in total.
The Conspectus level indicator is an alpha-numeric code used to indicate both the existing collection strength (ECS) of a subject, and the current collecting intensity (CCI), i.e. what a library already holds, and what it is trying to achieve in terms of collection-building.
The Level Indicator has six levels:
•	Level 0: out of scope: the Library does not collect in this area. 
•	Level 1: minimal: a collection for which only few selections are made beyond introductory/very basic material 
•	Level 2: basic information: a collection of up-to-date materials which serves to introduce and define a subject; a basic information collection can support general enquiries, school and some undergraduate instruction, but is not sufficient to support advanced undergraduate courses. 
•	Level 3: intermediate: a collection containing a broad range of resources adequate to support undergraduate instruction and work at less than research intensity. 
•	Level 4: research: a collection containing current and retrospective resources which can support postgraduate and independent academic research; the collection will provide materials in all appropriate formats and languages. 
•	Level 5: comprehensive: a collection which includes, as far as is reasonably possible, all significant works of recorded knowledge in all applicable languages for a defined and limited field; the aim, if not the achievement, is comprehensiveness. 
The Language Coverage codes are:
•	E: principally English-language material 
•	F: principally English-language material but with a selection of material in other languages 
•	W: no restriction by language 
•	Y: principally in one language other than English, from one linguistic or geographical area 
In addition to the Level Indicators, there are two free-text areas that can be used to supply additional information. Scope Notes are used at the Division or Category Level to give an overview of a library’s collecting policies; Comments are used at the subject line level to supply a note on a particular collection.
3.1.4	The use of Conspectus in Scotland
The decision to adopt the Conspectus in Scotland programme took place within the then Working Group on Library Co-operation, now the Scottish Confederation of University and Research Libraries (SCURL) in 1985. The members involved were the then eight university libraries (Aberdeen, Dundee, Edinburgh, Glasgow, Heriot-Watt, St Andrews, Stirling and Strathclyde), the major public libraries in Edinburgh and Glasgow, and the National Library of Scotland.
The aim of adopting the Conspectus methodology in Scotland was influenced by the following factors: a desire to build up a co-ordinated ‘national’ resource in Scotland; the recognition that resources were under pressure and likely to remain so; a desire to provide the best possible services for our users from the available resources; a desire to establish the collective strengths and weaknesses of our respective collections; a desire to find an existing methodology to utilise if one existed. A primary recognition in Scotland was that the Conspectus methodology was not perfect, but it existed, and we would not have the resources ourselves to devise an alternative system.
A major decision in our application of Conspectus was the adoption of a fast-track approach to Conspectus. This had the aim of completing the survey within one year in order to give a general map of strong and weak collections and collecting intentions, rather than taking a more fundamental approach to the methodology. From our earliest examination of the methodology we had recognised that it was not a perfect system (as had also been recognised in North America). However we also recognised that it is unlikely that a totally satisfactory system for measuring collections could ever be devised. Since we wanted to have a fairly practical overall map of Scotland’s strong and less strong research collections as a basis on which to carry out subsequent work, we came to the conclusion that we should utilise Conspectus in a pragmatic way on a short timetable and then refine and use the resulting information in the way that we wanted.
The programme began in October 1986 and was completed in September 1987. The outcomes from that programme were:
1.	A map of the collection strengths and weaknesses of Scotland’s research libraries 
2.	A clear understanding of the mission of each library in its collection-building 
3.	An understanding of the active current collecting policies of each library in each subject field 
4.	An overall picture of the weak areas of Scotland-wide collecting. 
In terms of the resources used by the initial Conspectus assessment, the participating libraries (11 in all) took a total of 4,500 hours; and at the time the costs were estimated collectively by the participating libraries as approximately £35,000.
Having achieved these objectives from Stage 1, the next stage of co-operative work was:
1.	to accept that, given the financial climate, it was unlikely that weak areas or absence of coverage could be actively strengthened in any way by assigning more resources (except where a university library, for example, might build up specific subject areas if new teaching courses were introduced for some reason); and
2.	that having identified where there were strong collections, we should move to a position where we had examined these collaboratively and then tried to work towards a system of distributed responsibility for the whole of Scotland.
Stage 2 was the Co-operative Collecting Responsibilities (CCR) Programme, which was implemented in 1990. The objectives of this Programme were:
1.	To ensure that research-level collections in given subject fields were maintained in Scotland 
2.	To engage in a voluntary programme of accepting co-operative collecting responsibilities which would identify in all subject fields the number of collections that were actively to be maintained 
3.	To enable individual libraries to make decisions about their own collection policies in the light of knowledge about other libraries’ intentions. The National Library might, for example, decide not to continue to collect at research level in a subject field if it became clear that there was already good coverage across the country (given that there were no additional factors to take into account) and might then build up another subject field for which there was a collective demand 
4.	To find a way to keep this information up-to-date. 
The Programme worked in the following way: all libraries with a Level 4 or 5 Current Collecting Intensity (CCI) were asked if they wished to accept a CCR in that particular subject. Where no Level 4 or 5 collections were recorded, a group of up to three Level 3 collections were asked if they wished to accept a CCR as a group. The theory behind this was that US experience had shown that three libraries, each with a Level 3 collection, tend to be so diverse in actual titles as to represent collectively a research-level provision. The principles underlying the implementation of the CCR Programme in Scotland were:
1.	Accepting a co-operative collecting responsibility (CCR) did not commit an individual library to any additional expenditure: it simply involved a commitment to continue to maintain a research level collection. 
2.	The only additional responsibility was if a library found that it could not continue to maintain a research level collection for which a CCR had been accepted, the library must inform other libraries in the Programme. 
The co-ordinating role in the implementation and monitoring of the CCR Programme has been taken by the National Library of Scotland.
Stage 3 of the Programme, following completion of the CCR Programme, was to mount the information about the existence and location of research level collections in Scottish research libraries online. The objectives of this Programme were:
1.	To provide researchers with information about where research level collections in specific subject fields could be found in Scottish research libraries 
2.	To show which libraries had undertaken to maintain specific collections at research level 
3.	To keep the information up-to-date to reflect any changes (expected to be minimal) in the collecting intentions of libraries in the programme 
4.	To find a way to enable individual libraries to make any changes locally attaching a note of the date of the change, with overall co-ordination of the system being provided by NLS. The data has now been mounted by Strathclyde University Library as Research Collections Online (RCO). Some editing work has yet to be carried out and the intention is to try to find a means to enable this work to be implemented as soon as it can be arranged. 
The general approach of the current level of work is:
1.	RCO provides researchers with information about where research level collections are located; and
2.	the online catalogues of individual identified libraries can then be searched for item level titles or subject searches.
Clearly, until retro-conversion has been completed in all the libraries involved, this will not work comprehensively, although that is the ultimate aim. The main objectives of this Programme now are:
1.	To keep the information up-to-date with any changes being made locally at the level of the individual library, with overall monitoring from NLS. 
2.	To add research level collections maintained in the ‘new’ Scottish universities that had not been created at the point of the original CCR Programme. 
A new stage of work is to identify a means of using the information gained through RCO as a means of sharing preservation responsibilities among Scottish research libraries (through the Shared Preservation Project that is currently being devised).
Another development of relevance is the eLib-funded CAIRNS Project. Consideration is being given to the future relationship between RCO and other relevant Scottish resource-sharing programmes, and the CAIRNS Project.
Ann Matheson, National Library of Scotland
3.1.5	CAIRNS, RCO, Conspectus, Collection description
CAIRNS [CAIRNS] aims to integrate around 25 Z39.50 compliant catalogues or information services of CAIRNS sites across Scotland into a ‘functional and user-adaptive’ test-bed service. This will offer search and retrieve capabilities across a ‘clump’ of services comprising all of the individual CAIRNS bibliographic databases, together with various services describing electronic resources.
The project will take advantage of SCURL’s Web/Z39.50 Conspectus-based research Collections Online (RCO) service as the basis of a subject-based dynamic clumping service. This will provide users with dynamically generated subject-based ‘sub-clumps’ of selected CAIRNS services to search via Z39.50. The feasibility of extending the data to:
•	include data on the collections of ‘new’ universities in Scotland 
•	include restricted data on local-access-only databases 
•	enable users to be presented with subject-based sub-clumps of catalogues of electronic resources (BUBL-LINK, SLAINTE, CATRIONA II and Strathclyde University’s Z39.50 compliant Web server 
will also be considered, although in some cases, outwith the scope of the project. In addition, the recent availability of BUBL’s 5:15 service based on the JISC Committee on Electronic Information (JCEI) subject categories may offer possibilities for examining possible mappings between Conspectus and the JCEI subjects.
The RCO service has only recently been made publicly available by SCURL [SCURL]. The service allows users to search SCURL’s collection description database via the Web or Z39.50, although the initial structure of the database is more suited to Web access and the way that the data is held may have to be re-worked to take account of the requirements of utilisation within CAIRNS, particularly in respect of Z39.50 search and retrieve operations. The RCO service as presently implemented provides in-depth descriptions of collections held in the eight ‘ancient’ and ‘modern’ universities in Scotland, together with those in the two main public libraries and the National Library of Scotland.
Although Z39.50 access is possible, RCO is currently designed mainly for Web access. Users can
•	browse RCO by subject - perform simple searches of subjects or codes 
•	perform ‘advanced’ searches combining subject terms, library and level specifications 
•	display all RCO subject headings 
•	display specific library holdings 
•	obtain help and information on Conspectus (three full text papers) 
The result of a search or browse operation on the service is typically a record that looks like this:
ART 113 FRANCE 

Aberdeen University 
Level: 3

Glasgow University
Level: 3

National Library of Scotland, Edinburgh
Level: 3
[Note: Level 3 = instructional support; Level 4 = research; Level 5 = comprehensive]
Having retrieved such a record identifying (presumably) libraries holding collections of interest, the user may then click on the name of each library in turn in order to search the local catalogue. There is an assumption that geographical considerations may come into play at this stage and that in the above example a researcher in Aberdeen (for example) may elect only to search Aberdeen University and the National Library of Scotland in Edinburgh and not Glasgow University. Whatever may be the case in this respect, the user, having identified the library catalogues that are of interest to her, must then effectively exit from the RCO system and search the local catalogues individually. Thus, in the example above, she would connect to each of the catalogues in turn and repeat her subject or named item or class search in each, retrieving three distinct result sets in three distinct systems, using three quite different user interfaces. There would of course be the appearance of a unified system since most of the systems concerned are accessible, like RCO itself, via a Web browser. But there is no real integration, as is clear from the fact that the result sets are difficult, if not impossible, to combine together into one set.
The proposed CAIRNS dynamic clumping service would build on the present service and allow the user to conduct a subject-based collections search as above. However, retrieval in this case would take the form of a dynamically generated clump of appropriate Z39.50 servers that could then be searched simultaneously as a group using a broadcast search facility. The initial aim is to improve upon what is possible at the moment with RCO. Once the RCO search is completed, and the clump of servers retrieved, it will be possible to search all of them in what is effectively a single operation - so that users seeking to locate works of interest to them in ‘collections’ distributed across Scotland could, in effect, search a single virtual catalogue of the ‘collection’ and retrieve a single set of results (as opposed to two or three or five, which is the current position). The wider aims of the project include:
•	examining the feasibility and value of extending the functionality to include the automatic inclusion of the search terms used in the RCO search in the distributed catalogue search (more difficult than it sounds); 
•	exploring the possibilities and limits of Conspectus-based collection descriptions as a means of facilitating user selection of manageable clumps of servers appropriate to their particular subject interests both within Scotland and within the wider world. 
CAIRNS research in these areas is at an early stage but the following are likely areas of investigation and interest:
3.1.6	Retrieval within ‘Collections’
There is currently no direct connection between an RCO record describing a collection and the items within an individual catalogue that ‘comprise’ that collection. The RCO record contains no information about the catalogue record and the catalogue record contains no information about its RCO subject categories or levels. Having identified a catalogue or set of catalogues containing a ‘collection’ of interest, the researcher might reasonably assume that her subsequent search will be carried out only within the ‘collection’ she is interested in, an assumption that might well affect her search strategy and results. However, this is not currently possible and, indeed, may never be possible. Whether or not it is important that it should be possible is still a matter of debate within CAIRNS, and it will be interesting discover whether user evaluation of the service clarifies the issues in this area. If it does, this may help identify desirable improvements in the way Conspectus terms relate to local records in the Scottish context, although such improvements are only likely to be implemented if they do not have a negative affect on the ease of maintenance of the Conspectus data.
3.1.7	Scalability
There are Conspectus-based projects in a number of other countries (see below). However, there is no reason to believe at the moment that Conspectus is likely to gain universal acceptance as an approach to collection description, even within research libraries, nor is it necessarily the case that it is universally applicable in any case. A major concern within CAIRNS (and, indeed, within eLib) is that mechanisms put in place as a result of the work of the project be scalable. This, in the context of RCO and Conspectus and dynamic clumping, includes not only technical scalability but also universal applicability and the likelihood of some reasonable level of universal acceptance. In respect of these considerations, questions for CAIRNS to consider include:
•	Is Conspectus a feasible approach worldwide or, at least, one of a few such schemes? 
•	If not, is it still useful in the Scottish context? Can it be mapped to other schemes? 
•	Is a worldwide network of RCO-type collection description databases feasible and of likely practical value? 
•	How applicable is the Conspectus approach to the selection of collections of electronic materials or teaching materials included in some CAIRNS databases? 
•	How well does it relate to the JCEI subject categories used in BUBL 5:15 [BUBL515]? 
3.1.8	Explain
Nothing that has been undertaken so far in relation to SCURL’s work with Conspectus and RCO has been undertaken in the context of any possible future relationship with the use of the Z39.50 Explain service. This has an important bearing on the design of the dynamic clumping service and will focus attention on a number of areas:
•	If a working Explain service exists for every CAIRNS server, and all of the clients in use are able to make use of these services, the CAIRNS version of RCO need only contain collection description information plus connection details and database name or names. If, as is likely in the short term, such services do not exist, then either the CAIRNS client(s) must be pre-configured with information about attribute sets and record syntaxes, or the CAIRNS version of RCO must itself contain this information. Which is the best approach, given that Explain services may exist in the longer term and that the pre-configured approach will likely make the database less useful to other ‘clumps’ and Z39.50 users in general? 
•	If as seems likely enhancing the RCO data is the best approach in the short term, how can it best be future-proofed against the eventual development of Explain services? 
•	What plans do the various CAIRNS suppliers have for implementing Explain facilities and how can any RCO-based implementation be future-proofed in this area? 
There are almost certainly other issues, but these are some of the main themes. There is little likelihood that CAIRNS will resolve all of the associated questions satisfactorily in its two-year lifespan. More probably, the best that can be hoped is that it will clarify one way forward in respect of collection descriptions and will identify the options that exist as regards their use and usefulness in dynamic clumping and distributed searching.
3.1.9	Other Conspectus-type activity
The countries that have taken the original Conspectus methodology and built upon it are:
The Netherlands 
Conspectus values are added at item level in the PICA database (the union catalogue of The Netherlands). The Dutch have also implemented a co-ordinated resource-sharing programme, and in a sense have followed the Scottish approach fairly closely. 
Australia 
Australian research libraries have used Conspectus to assist them to develop a co-ordinated ‘national’ collection. They are also currently looking at its potential for sharing preservation responsibilities. 
Belgium 
A pilot was carried out about two years ago, and there is now interest in developing this approach further. They are in touch with the Scottish approach. 
Wales 
A Conspectus exercise involving Welsh research libraries has been completed. 
A number of other countries began to use Conspectus methodology and have not continued to pursue it for a variety of reasons:
Canada 
A lot of resources were invested in the Canadian Conspectus programme but a fundamental approach was taken to its implementation and so the process took very much longer. It appears that the programme got waylaid and nothing further was done for some time. However in autumn 1997 there was some general discussion about taking up the idea again, as a result of the severe funding cuts experienced. 
France 
Considerable effort was expended in translating the worksheets into French (with the assistance of the Canadians). However, when the new BnF plans were projected, the priorities for French libraries were changed internally (by the Ministry of Education) to retroconversion of catalogues and digitisation. 
USA 
A number of libraries and groups of libraries have applied Conspectus and some individual libraries have taken the results either for resource-sharing activities or for preservation. However, there were some practical issues regarding the ‘ownership’ of Conspectus between ARL and RLG. In addition, RLG priorities have moved recently very much in the direction of digitisation and digital projects. 
British Library 
The BL carried out a Conspectus-based review of its own collections in the 1980s, and it appointed a National Conspectus Officer to co-ordinate activities across England (and, indeed, the UK). The lack of interest from English libraries caused them to phase this post out about two years ago, and it appears that they are not keeping their own information up-to-date. 
3.1.10	Results from Conspectus implementation
The main point about the Scottish use of Conspectus is that it really provided a foundation to begin the work of identifying research level collections. In itself it did nothing more than that. The important aspect of the Scottish programme has been the further stages to which we moved from this first level mapping made possible by the use of the Conspectus methodology. This has enabled us to:
1.	Agree a co-ordinated programme for the maintenance of research level collections across the country, and a means of sharing this responsibility among our research libraries. 
2.	We have created subject specialist groups (e.g. Official Publications, Visual Arts, North American Studies) who have taken the primary Conspectus information and used it (along with other information) to implement more detailed resource sharing activities where these are possible; and to promote the collections in these subject fields more actively for the benefit of researchers. 
3.	To form a possible basis for further resource sharing such as responsibility for preserving collections. 
4.	We have had experience of collaborating through a programme that tested us quite thoroughly and gave us a good foundation for future collaboration. 
We do not expect to maintain the base line Conspectus information any further since its purpose is now superseded. Our main interest now is in Research Collections Online, keeping it up-to-date and in developing other resource-sharing activities such as sharing preservation responsibilities.
3.1.11	Overall findings: Conspectus
1.	The original Conspectus methodology is very time-consuming and labour-intensive if it is approached in a fundamental way. 
2.	It is our contention that you do not achieve a better quality of information by taking this approach, than a ‘fast-track’ approach. 
3.	In our experience the useful aspects of the initial Conspectus methodology are the Level Indicators and the Language Indicators. 
4.	In our overall use of the methodology and its aftermath, we have found that the most useful aspect is the second stage of the Co-operative Collecting Responsibilities (CCR), if the objective of a group of libraries is to identify where strong collections are to be found and maintained across a region or country. 
5.	There are important advantages to research libraries, in the current funding climate, if they are able to show that they are actively collaborating to make the best use of the available resources for their researchers. The use of Conspectus, and even more so the CCR Programme, enabled us to do this in Scotland and this has been beneficial. 
Dennis Nicholson, Strathclyde University
3.2	ISO 2146
This section examines the scope and utility of the ISO 2146 standard: Documentation - Directories of libraries, archives, information and documentation centres, and their databases. The latest edition of the standard predates the explosion of the Web and networked information capabilities, and comment will be made on its initial primary function and continued applicability in an online networked retrieval context.
3.2.1	Scope
The scope of the standard as identified in its paragraph 1 is stated as:
to assist in compiling directories. The rules of this standard concern international directories, national directories published in bi- or multilingual countries, and national directories intended for international use. The standard should be used for the collection of the appropriate data and for the publishing of the directories as well as for the exchange of data.
An example of how some data elements may be used could be presented:
Data element	Tag	Example data	
Official name	aaa	International Organization for Standardization	
Official name in other languages	aac	Organisation Internationale de Normalisation	
Language of official name	aah	eng	
Abbreviation/Acronym	aal	ISO	
 	 	 	
Name of Collection	faa	Current standards in force <1>	
Name of Collection	faa	Superseded Standards <2>	
Name of Collection	faa	Draft and consultative standards <3>	
Name in further languages	fac	Normes en force <1>	
Previous Name	fap	Defunct standards <2>	
Address details	fca-fcn	Address <1>	
Address details	fca-fcn	Address <2>	
Address details	fca-fcn	Address <3>	
Coverage/mandate	hac	All standards currently supported by ISO membership <1>	
Coverage/mandate	hac	Includes DIS and papers for consultation by ISO members <3>	
Language coverage	hal	Eng, fre, ger, ita, spa, ...	

Some implications of this table are discussed below.
The principal element to note from this scoping introduction is that the standard is defined for the collection of data for print publishing, and this core element is reflected in the overall shaping of the data within the standard definition. ISO 2146 was originally published in 1972, and the revision of 1988 was defined ahead of the surge in availability of information in worldwide computer networks. It remains a standard for the accumulation of data for presentation in a linear format, and not for retrieval in an interactive data retrieval context.
This can be shown in several areas:
•	Institutional name and relationships.
The structure of the standard reflects an approach to an institution so that the central details of an organisation may be recorded and expressed simultaneously in a display with its constituent parts, so that for instance the main body is recorded under tag ‘aaa’ with each collection or sub-unit enumerated in multiple tags ‘faa’. This provides for a logical structure in a printed directory, but will cause problems in a structured online retrieval system, where a hierarchical approach could be adopted to ensure parity of entries. Structurally, the 2146 approach is also weak in showing relationships between multiple instances of a data element. As shown in the above example, for each item ‘faa’, a sequence of alternative name tags ‘fac’ to ‘fas’ are provided, followed by address details ‘fca’ to ‘fcn’; mailing address details (‘fd’); communication details (‘fn’); and indeed 20 additional data element groups. It is the input operators’ responsibility to ensure linkage between the data elements by providing a linking numerator, which is very prone to error, and difficult to interpret cleanly for display. The example shows an extract from a hypothetical record, with hierarchical linkages difficult to see and confirm. 
•	Standardisation of data within data elements
To its credit the standard refers to additional ISO standards quite extensively, to support the data entry for consistent elements such as dates (ISO 2014); languages (ISO 639); country codes (ISO 3166). However, in other - and many - tags the definition of data elements is weak, and does not provide for international entry or retrieval: 
For example:
Data element: Archival finding aids (Tag ‘pcn’) is exemplified as guides, inventories, special lists, indexes
and more critically
Data element: Description of services (Tag ‘rad’) in a single tag is called to provide:
•	Description of printed information service 
•	Description of database 
•	Description of enquiry service 
•	Description of dialogue participation service 
•	Description of profile service 
each of which enumerates a list of specific attributes for the service:
•	name of database 
•	type of data 
•	coverage (chronological and geographic) 
•	recorded data elements 
•	access 
•	format. 
This approach is fine for a linear production, but is not clearly focussed to allow the type of recording and therefore retrieval that is required for a digital collection.
•	Bureaucratic information. In the world of information retrieval, users are mainly interested in access to the piece of information that they require, and do not need to know full details of the bureaucracy of the organisation that is presenting the information. ISO 2146 reflects the printed directory requirement for data on the business approach, and provides copious fields for recording the name and title of the head of the organisation, and the contact point for each of the collections - with organisational detail. Details of organisational history and budgets are also provided for. 
3.2.2	Currency of the Standard
Within ISO, the responsibility for this standard falls under Technical Committee 46 (TC 46: Information and Documentation), and within TC 46, to SubCommittee 9 (SC-9: Presentation, identification and description of documents). It was originally prepared by a former subcommittee of TC 46 (SubCommittee on Documentation), and passed to SC-9 in the late 1980’s. As SC-9’s activities are more focussed on bibliographic data - Bibliographic filing principles (ISO 7154); Title leaves of books (ISO 1086); International Standard Music Number (ISMN) (ISO 10957) as examples - this standard which is concerned with collections and institutions now stands apart from the mainstream of SC-9’s activities.
ISO Standards are subject to review every 5 years: in the 1993 review of the standard there were 12 votes in favour of confirming the standard, with 2 in favour of revision, and 1 in favour of withdrawal. A further review was scheduled to take place between November 1998 and March 1999, and a growth in votes for revision or withdrawal may be expected, according to the SC-9 Secretariat, in view of the overall changes in networked infrastructures: as formulated in 1988, this standard predates the World Wide Web, and the availability of databases across the Internet. It therefore makes little reference to computer networks generally. A substantial revision would therefore seem to be appropriate.
3.2.3	Current Applications
It has been very difficult to discover working applications of ISO 2146. The TC 46/SC 9 Secretariat reports no feedback on actual implementations. Paragraph 5 of the standard calls for the establishment of a Maintenance Agency, but none was ever established, leading to some of the potential problems described above, and almost certainly ensuring that the standard will lapse with lack of ongoing support.
In the absence of a Maintenance Agency, it would still be possible to adapt the standard for controlled usage within a defined application, and particularly where such an application, although referring to widespread institutions, is maintained centrally. In a controlled capacity, it should be possible to employ the standard for administration purposes. The French InterLibrary Loan Service for Academic Libraries, run by the Agence Bibliographique de l’Enseignement Supérieure (ABES) kept a database based on ISO 2146 to detail the library members of the service, giving details of the participant institutions, with addresses and contact details, and indications of usage restrictions. As ABES is currently moving to a PICA implementation, it is not know n whether the database will be maintained in its former structure. In its call for tender for NDIS, the National Library of Australia indicated that ISO 2146 would be among a number of standards used for directory structures; again in their AMICUS implementation, it is not known whether use of the standard remains a goal.
3.2.4	Potential
It is not possible for the standard in its current iteration to be used as the basis for networked directories of collections, and much work would need to be applied to revise the standard for use in the wider network context. In particular, the following actions would be required:
•	The establishment of a maintenance agency 
•	Definition of a collection, or determination of a hierarchical structure within the standard, to ensure focus and linkage of required data elements 
•	Detailed enumeration of data elements to ensure no ambiguity 
•	Detailed identification of codified elements to ensure exactness of approach and internationalisation of meaning 
•	Definition of revised elements for network connectivity to reflect advances in technology 
•	Definition of new elements for access control 
•	Definition of revised elements for terms and conditions of use 
Martin Fisk, Aurora Information Technology
3.3	Z39.50 Profile for Access to Digital Collections
The purpose of the Z39.50 Profile for Access to Digital Collections is to support libraries and other institutions who are creating a growing number of collections of numerous, diverse objects, both digital and physical that are often organised hierarchically and may be physically distributed across servers. The profile specifies a conforming subset of Z39.50-1995 to address this area.  In particular it provides a mechanism for access to digital collections organised via descriptive information, i.e., metadata. In order to achieve this purpose, the profile provides semantics for navigating digital collections, and to locate and retrieve objects of interest.
A more detailed summary of the Z39.50 Profile for Access to Digital Collections is available as part of a separate report: 
•	Analysis of the Z39.50 Profile for Access to Digital Collections and the Z39.50 Explain Service
3.4	ISAD(G) - General International Standard Archival Description
ISAD(G) is a set of general rules for archival description which is intended to be broadly applicable to descriptions of archives regardless of the nature or extent of the archives described or the level of description [ISADG]. The rules guide the formulation of information in each of 26 elements that may be combined to constitute the description of an archival entity. The primary value of the rules is that they support the creation of consistent appropriate and self-explanatory descriptions that in turn facilitate the retrieval and exchange of information about archival material.
The standard was developed by the Ad hoc Commission for Description of Standards of the International Council on Archives (ICA) with support from UNESCO and adopted by the ICA in 1994. Members of the Commission took as their starting point the British Manual of Archival Description, the American AACR2 and the Canadian Rules for Archival Description (Ottawa 1990 and continuing), and filtered these especially across practice in Spain, France, Portugal, Australia and Malaysia. Drafts of the standard were widely circulated and discussed and the resulting text has been mapped back to MAD and MARC and has subsequently also successfully mapped to Encoded Archival Description (EAD). In 1995 recipients of Non Formula Funding in the Humanities Special Collections funding for cataloguing archives agreed to utilise ISAD(G), as also have the Public Record Office and the Scottish Record Office. The development and successful test of a Z39.50 profile for archives which is based on ISAD(G), and the stated intention of the National Council on Archives that ISAD(G) would form the core descriptive standard, has added to the momentum of adoption of ISAD(G) in the UK. Training courses on ISAD(G) are now heavily oversubscribed, although wholesale retroconversion will inevitably depend on the release of further funding either under the recently announced Research Support Libraries Programme or the Heritage Lottery Fund and New Opportunities Fund public library initiatives.
On publication, it was stated by the Ad hoc Commission that ISAD(G) would be reviewed in four years time. An international call for comment by professional organisations has now gone out. Comment from the Society of Archivists suggests that the minimum number of mandatory elements should be increased for fonds level description, or sub fonds where appropriate, and several others added. (Sub fonds are major groups of archives within a large archive such as the records of an individual company within a large multinational). In practice this recommendation, if adopted, would ensure that minimum fonds/collection level descriptions would expand to offer the functionality of a guide level entry.
Minimum ISAD(G) for a collection level description are cited below:
Reference code 
Country code in accordance with ISO 3166 Codes for the representation of names of countries (GBR), followed by repository code in accord with national practice (numbers allocated by the Royal Commission on Historical Manuscripts); followed by local repository specific archive code and associated numbers. 
Title 
Formal title or concise title conveying authorship, subject matter and form of material. Because formal titles often do not convey much information about content the Society of Archivists will suggest that the or is deleted. To discourage the expansion of title information beyond brief identifying information, it is also suggesting that scope and content element be made mandatory for fonds and sub fonds. 
Date of creation of material 
This may be a single date, a span date or a broken span date such as 1890-1920, 1949. Where the subject matter described is earlier than the dates of element creation, this will be expected to be conveyed in the scope and content. 
Level of description 
A simple statement of level and for the present purposes would be fonds or sub fonds. Other possibilities are series, sub series, file and item. 
Extent 
A statement of the quality, bulk or size. This may be given as number of boxes, files etc. or a measurement of linear or cubic metres or feet. Whilst it can be useful to state the number of boxes etc., the Society of Archivists takes the view that the measurement should be given in cubic metres. 
To establish a collection level description, equivalent in utility to a guide level description, archivists working on ‘Follett’ projects (projects funded by the Non-formula Funding of  Specialised Research Collections in the Humanities) are already also routinely using at least all of the elements given below. The Society of Archivists will also be recommending to the ICA that they are made mandatory for fonds and sub fond level descriptions.
Name of creator 
Name(s) of creator or creators of material if they do not appear in the title. 
Administrative/biographical history 
Brief description intended to place material in context and make it understood. This is expected to record any significant information on the origin, progress, work and development of an organisation or the life and work of the individual responsible for the creation of fonds/subfonds. 
Scope and content 
Brief description sufficient to identify the subject matter and form material to enable users to judge its potential significance. 
Access conditions 
Statement of any condition that may restrict access, including special permissions and closures. 
The Society of Archivists will also recommend the inclusion of a new mandatory element, date of compilation and/or revision of the catalogue description. A number of Follett fund holders are already using a note field element to provide this information but it is regarded as sufficiently important to merit an element in its own right.
The Society will also recommend the inclusion four further elements for index entries to persons, places, and corporation names and for subject authority entries. The formulation of names is covered by two sets of rules outlined below.
3.4.1	ISAAR (CPF): International Standards: International Standard Archives Authority Record for Corporate Bodies, Persons and Families.
ISAAR (CPF), like ISAD(G), was prepared under the auspices of the ICA Ad hoc Commission on Description Standards and received endorsement from the ICA in 1996 and more recently from the Society of Archivists. In formulating its views the Commission drew upon work then in progress in Canada and the United States as well as work on international authority records done by the International Federation of Library Associations and Institutions (IFLA) such as Guidelines for authority and reference entries (1984). Its purpose is to support the preparation of consistent, appropriate, and self-explanatory description of corporate bodies, persons and families.
3.4.2	National Council on Archives: Rules for the Construction of Personnel, Place and Corporate Names (1997).
Broadly parallel in intention to the ISAAR (CPF) the declared purpose of the NCA Rules is to assist cataloguers of archives and manuscripts in forming names for persons, places and corporate bodies which are unique and readily identifiable by users. Like ISAAR (CPF) it has been adopted by the Society of Archivists, of which the majority of its working committee were members. Sources drawn upon included the Anglo-American Catalogue Rules, 2nd edition (London 1988), the rules for personal names drawn up by the editorial board of the New Dictionary of National Biography, the Canadian Rules for Archival Description and Steven L Hensen’s Archives, Personal Papers and Manuscripts: a Cataloguing Manual for Archival Repositories, Historical Societies, and Manuscript Libraries, 2nd edition (Chicago, 1989). Because many archivists work within a larger library environment, departures from AACR2 were kept to a minimum but these departures were regarded as essential by the author of the rules.
Of the two, the NCA Rules, as the more detailed exposition of UK practice, has found a more immediate acceptance than ISAAR (CPF) but it is widely understood that there is no conflict in principle between the two. The NCA Rules will form the basis of authority lists which will be expected to provide one of several access points to a planned national network for archives, and hence will be the preferred approach for the implementation of additional ISAD(G) elements for fonds/collection level description for names. Concern has, however, been voiced about the adequacy of rules for place names both for the UK, and especially for overseas.
The Public Record Office, the British Library, and other major national repositories have all agreed to contribute data toward the establishment of national authority lists, and as far as immediately practical a number of Follett fund holders are already employing the rules for names within catalogues and indexes presently being compiled or revised.
The divergence from AACR2 is, however, an issue for the wider information community and there would seem to be merit, in the context of hybrid library developments, in following the museums community lead in developing fuzzy matching for library and archive authority lists to ensure that all rules meet the purposes for which they were designed.
Patricia Methven, King’s College London
3.5	EAD - Encoded Archival Description
EAD is a SGML Document Type Definition (DTD) which can fully present the hierarchical arrangement of archival catalogues [EAD]. It was initiated by the University of California at Berkeley, and its development has been supported by the Society of American Archivists Standards Board. Following beta testing, the EAD Working Group of the Society of American Archivists Committee on Archival Information Exchange, including interested implementers from Britain and Canada, reviewed proposed changes to the DTD. These included consideration of the relationship of EAD to ISAD(G), MARC and the Canadian Rules for Archival Description. A revised DTD is now being tested and is available for comment.
Interest in the opportunity EAD offers to provide effective searching of hierarchies without major restructuring of catalogues is widespread in the UK. There was an early consensus within the JISC NFF Archives Sub Committee that the National Networking Demonstrator Project should include EAD tagged catalogues, and within the National Council on Archives Networking Policy Committee that any national system should accommodate EAD catalogues. Its adoption is also being encouraged by the Research Libraries Group in the UK, and Calm 2000 Plus advertise conformity to EAD. There is, however, considerably less support for EAD among European colleagues, at least some of whom regard it as Anglocentric.
Despite the interest in the UK, there is not yet a consensus that EAD is the preferred way forward for all archive repositories. Some are waiting to review the broader impact of XML, and also the findings of the National Networking Demonstrator Project which will include comments on the respective merits of delivering catalogues prepared in a variety of software and standards to the Web using Z39.50. Concern also focuses on the time taken to encode and the real gains of the end product.   There is also the fact that current Web browser technology cannot yet take advantage of text marked up using EAD and that additional software must be downloaded to enable it to be read across the Internet. Although EAD is software independent, university repositories implementing EAD typically invest in Dynaweb and Dynatext software to get the best out of the standard. For its part the Public Record Office, in its plan to get all its finding aids into electronic form by 2001, is proposing to store catalogue data on a large relational database while output for users will be generated in EAD.
Patricia Methven, King’s College London
3.6	
Other archival approaches
3.6.1	Structured data and SGML
To date the majority of searchable electronic catalogues have relied on the heavy structuring of data, and have commonly also used forms of relational databases. In terms of software, market leaders for some years were CAIRS, MODES, STATUS CLIO and ACCESS. STATUS CLIO is the software of choice for the Scottish Record Office’s SCAN project. Dominant among new entrants to the market place is CALM 2000 Plus which is being developed in conjunction with a number of County Record Offices and is deliberately being formulated to reflect recent developments with regard to ISAD(G) and Z39.50. All of this software has been used to support cataloguing at all levels of descriptions. SGML (Standard Generalised Markup Language), although of considerable interest to archivists as a tool to support the calendaring of individual documents or other detailed editorial work, was not generally regarded as useful until the development of Encoded Archival Description (EAD) and HTML.
3.6.2	HTML
Because of its ease of implementation, rather than its sophistication, a significant number of Follett fund holders are using HTML to deliver information onto the Web, including catalogues commonly prepared as Word documents. For collection level descriptions, in particular, this is being seen as an acceptable way of presenting data pending the development of an easy solution of greater sophistication. Searching is, however, recognised as crude, especially where there are runs of date brackets in biographical and administrative history elements, and scope and content notes inevitably lend themselves to false drops for combined date and subject searches.
3.6.3	Z39.50 and the National Networking Demonstrator Project
Part of the brief of the JISC NFF Archive Subcommittee was to research and develop strategies likely to facilitate networked access to archival catalogues. In scoping the task the Subcommittee took as its working premise that user access would be facilitated by provision of a single or limited number of gateways to a national network. This would provide cross sector access to archival catalogues held in the whole range of university, national, local and private repositories. Further, that it should be possible to search all levels of descriptions down to item or piece used in catalogues, and that any resultant structure should be capable of incorporating catalogues prepared using a variety of software. From the outset ISAD(G) was recognised as the dominant descriptive standard and Fretwell-Downing Informatics, a UK library and information systems supplier, was commissioned to develop a draft Z39.50 profile based on ISAD(G). The resultant draft profile reflected work already undertaken on the widely respected CIMI Z39.50 profile for museums.
The National Networking Demonstrator Project was subsequently mounted to provide a working test of multi-level cross searching of archival catalogues using Z39.50 including the development of a uniform front end to permit seamless public access to catalogues prepared using a variety of software. The project has been the subject of wide preparatory open discussion and follow up demonstrations have been attended by archivists from all sectors. The Demonstrator itself includes catalogues prepared in universities, the Public Record Office and local government, variously using CAIRS, MODES, CALM 2000, word processing, and EAD and HTML. Participation in the project required the provision of fonds level description, and a willingness to mark up catalogues in ISAD(G). Participants were offered a range of options in submitting data: those with their own servers could elect to link them into the Project, making their data available directly through system adaptation, or indirectly via export to a reference target.
The robustness of ISAD(G) as a descriptive standard has undoubtedly been confirmed by the project. The utility of Z39.50 as a means of supporting multi-level cross sector access for structured archival catalogues is also now widely recognised. The first phase of implementation of a cross sector national archival network planned to begin in autumn 1998 will build upon lessons learnt in the course of the Demonstrator and is expected to include the use of Z39.50. The final reports of the contractors Fretwell-Downing Informatics, and the Archival Consultant on particular lessons learnt, and appropriate next steps, including moves towards the formal registration of the profile, are awaited with interest. What is already clear, however, is that the Demonstrator has thrown back on the archival community a number of issues about how the various levels of description available are used, and also concerning access points. Some of these are already being reflected in the recommendations of the Society of Archivists concerning mandatory and new elements for ISAD(G). Others, like the handling of small collections, will need to be the subject of pragmatic decision at the time of a full-scale implementation of a national network.
3.6.4	American Heritage Project
Another approach to searching a range of archival catalogues is the American Heritage Project that, as a demonstrator, will bring together catalogues relating to nineteenth and early twentieth century American heritage with a view to studying issues relating to content and encoding. Based at the University of California at Berkeley, the project includes material from three other American universities. Collection level data is provided in the US MARC format and detailed catalogues in EAD. Presented as a union database, rather than the gateway approach of the Demonstrator, the intention is to support navigation from the union catalogue to individual detailed catalogues. Results are expected in 1998.
Patricia Methven, King’s College London
3.7	GILS
The aim of GILS, known both as the Government Information Locator Service and the Global Information Locator Service, is to make it easy for people to find information of all kinds, in all media, in all languages, and over time [GILS]. Information providers can describe anything with GILS including Web pages, books, data-sets, people, events, meetings and other physical objects. For networked information, GILS supports ‘hyperlinks’ for network access to the resource described and to related resources. GILS uses the Z39.50 search and retrieve protocol to provide access to information (GILS records) held in GILS compliant databases.
GILS has a Z39.50 application profile [GILSPROF] that has been approved by the Open Systems Environment Implementors Workshop/Special Interest Group on Library Applications (OIW/SIG-LA). The service was originally set up by the US Federal Government in order to provide the general public and its own employees with a means for locating useful information generated by the many government agencies. As such its constituency of use is very broad; literally anyone is likely to be able to search for resources using GILS. In theory, many different agencies are likely to use a variety of staff to generate their part of the overall GILS framework. In practice, some agencies are using GILS as generic metadata records for many resources and others are hardly using it at all.
GILS Data Elements are available in an extended attribute-value pair format - some of the elements are constructed from two or more sub- elements. For example, the Controlled Subject Index element is a grouping of sub-elements for Subject Thesaurus and Subject Terms Controlled. The grouping can be nested and is in this case; Subject Terms Controlled itself is a group formed from a repeatable sub-element called Controlled Term. There are approximately 90 GILS elements of which about 40 are considered to be core elements. The GILS Application Profile also provides a mapping to and from USMARC Tags and GRS-1 record syntax.
3.7.1	Collection level description using GILS
GILS records can be used to describe many different kinds of resources including ‘collections’ of resources, for example Web-sites, data-sets, CD-ROMs, etc. Furthermore, any level of aggregation can be supported in GILS. Typically, specific policies for any particular set of locator records are documented in a collections policy and/or ‘usage guideline’. A ‘collections policy’ documents the rules for inclusion of candidate locator records within a particular collection.
The Cross Reference elements of the GILS Element Set provide for the ability to describe relationships between records. The Cross Reference element subsets are also intended to be used inside Controlled Subject Index Subject Thesaurus structures to describe where to acquire and reference the thesaurus.
Andy Powell, UKOLN
3.8	WHOIS++ / ROADS
WHOIS++ is a simple Internet search and retrieval protocol that allows clients and servers to exchange structured records, based on WHOIS++ templates [WHOISTEMP]. The ROADS software [ROADS] utilises WHOIS++ to provide a suite of tools to help in the cataloguing of Internet resources, using a common resource description format based on IAFA templates [IAFA]. ROADS templates are compatible with WHOIS++ templates. 
ROADS templates look very much like the headers on an e-mail message or Usenet News posting, but many of the names are different. Resource descriptions, known as records, may either be created by hand, using a text editor, or entered via a Web form. Once a record is in the database it may again be edited via a Web form, or by hand. A number of default resource description templates are provided with the ROADS software. Each of these is intended for describing a particular type of resource:
•	DOCUMENT - e.g. a book or technical report 
•	FAQ - a Frequently Asked Questions document 
•	IMAGE - e.g. a GIF or JPEG object 
•	MAILARCHIVE - the location of a mailing list archive 
•	ORGANIZATION - information about an organisation 
•	PROJECT - information about a project 
•	SERVICE - information about an on-line service 
•	SOFTWARE - information about a software package, e.g. ROADS 
•	SOUND - e.g. an AIFF or WAV object 
•	TRAINMAT - information about on-line training materials 
•	USENET - information about a Usenet News conference 
•	USER - information about a person 
•	VIDEO - e.g. an MPEG or QuickTime object 
The ROADS software is typically used to build and maintain Internet Subject Gateways - catalogues of Internet resources. The subject gateway maintainer is free to change the templates distributed with the ROADS software, and new templates may be created either for describing new types of resource - or as alternatives to the distributed templates.
3.8.1	Collection Description using ROADS
The default templates provide a framework for describing commonly occurring objects such as documents, images and sounds. In addition, more nebulous things such as network services can be described using the SERVICE template. (See section 4.3 for a more detailed description of the ROADS SERVICE template.) In practice, most subject gateways using the ROADS software also use the SERVICE template to describe collections. 
More recently, an experimental ROADS COLLECTION template [ROADSCOLL] has been developed, based on the work of the eLib Collection Description Working Group [ELIBCOLL]. 
3.8.2	3.8.2 Examples
Here is an example of a completed ROADS SERVICE record:
Template-Type: SERVICE
Handle: SOSIG428
Title: UKBORDERS Information
Copyright-Owner: JISC, ESRC
Keywords: Geography, Digitised Boundary Data (DBD), Census,
 Demography, Population, GIS, Computer Aided Mapping
Description: UKBORDERS provides the digitised boundary data
 associated with the 1991 Census of Population. The boundary
 data allows users to map 1991 Census data systematically at
 any scale from small area to the whole country and can be
 used to design new zones from the small area building blocks
 and to integrate census data fully in geographical
 information systems. Academic staff and students of UK Higher
 Education institutions may access the digitised boundary data
 from the Universities of Edinburgh only after completing the
 required registration process. The data is also available
 through MIDAS at Manchester.
Subject-Descriptor-Scheme-v1: UDC
Subject-Descriptor-v1: 312 91
Admin-Email-v1: ukborders@ed.ac.uk
URI-v1: http://datalib.ed.ac.uk/UKBORDERS/start.html
Record-Last-Modified-Email: ecdh@ssa.bris.ac.uk
Record-Last-Modified-Date: Tue Sep 15 23:00:00 1997
Here is an example of an experimental ROADS COLLECTION record:
Template-Type:  COLLECTION
Handle: 918222860-6059
Title: National Child Development Study
Service-Identifier-v1: http://midas.ac.uk/surveys/ncds/
Description-v1: National Child Development Study, a longitudinal survey
 which follows the lives of a group of people born in Great Britain
 between 3 and 9 March 1958 (about 17,000 individuals). To date, there
 have been five attempts to trace all members of the birth cohort in order
 to monitor their physical, educational and social development. The NCDS
 is used for a wide range of research, including medical/health research.
 The data covers a long time period and includes a wide range of
 questions, plus physical measurements, such as weight and height.
Service-ChargingPolicy-v1: Free subject to site or individual
 registration.  Access requires the user to become a registered user of
 the dataset (http://dawww.essex.ac.uk/ordering_data/) and also to be
 registered with MIDAS (http://midas.ac.uk/regn.html)
Service-Admin-Name-v1: The Data Archive
Service-Admin-Identifier-v1: http://dawww.essex.ac.uk/
Service-Admin-Name-v2: MIDAS
Service-Admin-Identifier-v2: http://midas.ac.uk/
Subject-v1: Health Studies; Medicine and Dentistry; Anatomy and
 Physiology; Pharmacology and Pharmacy; Nursing
Subject-v2: Social Sciences; Economics; Social Policy and
 Administration; Sociology; Social Work; Anthropology; Politics; Law;
 Business and Management Studies; Library and Information Management;
 Communication and Media Studies; Education; Sports-Related Subjects
Destination: 
Comments: Automatically created from JISC Web pages.
Record-Last-Modified-Date: 1999-02-05
Record-Last-Modified-Email: a.powell@ukoln.ac.uk
Andy Powell, UKOLN 
Martin Hamilton, Loughborough University
3.9	Centroids
WHOIS++ [RFC1835] is a simple search and retrieval protocol for the Internet, designed to be straightforward to implement. The protocol supports only those features for which there is a demonstrable need. Additionally, the protocol does not require major computing resources nor does it require any special expertise of its implementers. In particular, WHOIS++:
•	Only supports one query language 
•	Constrains responses to follow a standard format 
•	Provides a small number of well defined ‘system commands’ 
A WHOIS++ client does not have to worry about whether the server will be able to handle the query that it sends, or that the server will respond with a format of results which it does understand. This is because in both request and response there can only be the one prescribed format for the data that passes between client and server. All WHOIS++ communications take the form of plain text, sent a line at a time. Text based protocols are considered easy to work with and this has resulted in their wide popularity on the Internet.
WHOIS++ supports distributed cross-searching via centroids and referrals.
3.9.1	Referrals and centroids
Cross searching is supported by WHOIS++ via two modes of operation. The first (obvious) method is sending the query to a number of different servers and collating the results. This method is undesirable from a bandwidth point of view, because it is likely to lead to a situation where every WHOIS++ service is being queried whenever a search is performed. It may, however, be desirable from the point of view of the WHOIS++ server to use this mechanism to collect usage and (potential) billing information.
The second method offers a way of discovering information held on other servers in addition to the one being explicitly queried. This is achieved via a ‘referral’. A referral gives connection information for another server that may be able to answer the query. Referrals are generated from forward knowledge gathered previously. In WHOIS++ terminology, this forward knowledge is represented as a summary of the contents of a server and is known as a ‘centroid’. Since centroids are only a summary, a referral resulting from a centroid match should not be assumed to be a genuine hit. For example, centroids have no way of knowing about word proximity information.
Each centroid is essentially a simple inverted index of the information in the database. For each of the types of record that have been used, and each of the attributes within those records, the centroid contains a list of all the index terms that have been found. To see how this works in practice, consider a database that contains the following SERVICE records:
Title: Social history server
Description: This server provides researchers in social history with
 resources that may be of interest.
Title: Military history database
Description: A database of pointers to military history resources.
Title: Medical history server
Description: A server that provides pointers to resources dealing
 with medical history
It can be seen that a number of words appear in the same attribute in multiple records. For example, in all three, the term ‘history’ appears in the value associated with the ‘Title’ attribute. The centroid of these records consists of the list of unique terms associated with each attribute. By unique terms we mean that we only record the first instance of an index term, even though it might occur repeatedly in the given attribute when the whole database is considered. Consequently, the centroid information associated with the ‘Title’ attribute would be:
Social
History
Server
Military
Database
Medical
Note that the original ‘Title’ fields in the records contained a total of nine words in the values whereas the centroid only has six words. The removal of redundant multiple instances of index terms typically makes the centroid associated with an attribute much smaller than the original data held in that attribute over all of the records in the database, which is a major difference when compared with the inverted index. Since real databases are much larger than this example, the chance that the same words will appear over and over again in multiple records is increased, and so the size of the centroid relative to the database is likely to be significantly smaller. We find that centroids for large data sets are quite large when viewed by themselves but relatively small when compared with the size of the original data from which they were derived.
If a database makes use of more than one object type then a centroid will contain a list of object types, the attributes contained in each type and the unique words within each attribute of each type. This would be treated separately from the ‘Title’ attribute of the ‘DOCUMENT’ object. This increases centroid size slightly as different object types are likely to share some common attributes and the unique words in these attributes will have to be repeated.
Although referrals and centroids have been presented here in the context of WHOIS++, there is no fundamental obstacle to using them with other protocols. For example, in the case of an open-ended protocol such as Z39.50, it would simply be necessary to develop a distributed indexing and searching ‘profile’ based on a common agreement on how best to implement these features in the Z39.50 context.
3.9.2	Building index servers
The combination of a simple search and retrieval protocol such as WHOIS++ with referrals and centroids offers us a simple yet highly sophisticated way of doing searches that span multiple databases. Once a centroid has been generated for a given collection of information, it can be made available to interested parties over the Internet. These interested parties are usually referred to as ‘index servers’, and there are two main ways for them to ingest centroids: 
3.9.3	Pushing centroids
The originating server has a list of index services with which it will share the centroids it may generate of its collection(s). In this case, each index server may be contacted in turn and informed that the centroid of the originating server is now out of date due to data changes. This has the advantage that the remote copy can be kept relatively up to date, perhaps by automatically sending a new version whenever the database is changed. However, care needs to be taken in choosing distribution times which are convenient for both parties - e.g. if they are in different time zones. It also means that new index servers may have to wait until they are manually added to the distribution list before they can get centroids. 
3.9.4	Pulling centroids
The index server knows about the servers that it receives centroid information from and regularly polls them for centroids, resulting in it ‘pulling’ centroids from the downstream servers. This is good from the point of view of the index server, since it can decide when it would like to pull centroids and how often. It may also be able to dynamically pick up centroid information from new collections that it has discovered - though there is no requirement that the information be made available to a previously unknown poller. It has the disadvantage that stale centroids may be left in the database of the polling server, and the index server might try to pull centroids at times which are inconvenient for the polled services - e.g. due to time zone differences. 
3.9.5	A centroid redux
Both models of centroid distribution are likely to be of use on the Internet. A single service might even use a combination of both methods. For example, consider a subject gateway having several satellite subject services specialising in particular kinds of information. It might gather centroids by polling these and from time to time push an updated centroid up to a higher level cross-disciplinary subject service. The main database might also contain centroids drawn from other WHOIS++ servers that were not part of this framework of satellites. From this it can be seen that not all centroid aware servers will find it worth picking up centroid information themselves. Many of these can be expected to make use of an index server, usually topologically close (nearby on the network) rather than collecting centroids. A typical scenario would involve the smaller services referring the user upstream to index servers if no matches were found in the database they first started working with. This decision of which index servers to refer the end user to could be based to some extent on search preferences (e.g. only medical/health related information) and/or lists of index servers which are considered to be worthwhile contacting - such as our hypothetical subject gateway index server. It may also be desirable to rank referrals in terms of the perceived relevance of the server - for example, eLib funded services choose to specialise in quality reviewed resources whereas services operated by volunteers may not be quite as particular. This may not be the case with the other centroids held by the index server. This inter-linking of index servers is typically referred to as a ‘mesh’, and is described in more detail in [RFC1914] and [RFC1835]. 
Martin Hamilton, Loughborough University
3.10	Dublin Core
The Dublin Core [DC] is a 15 element metadata set primarily designed to enhance resource discovery on the Web. Originally conceived for author-generated resource descriptions, it has also attracted significant interest from more formal resource description communities such as libraries and museums. The 15 elements are:
•	Title 
•	Creator 
•	Subject 
•	Description 
•	Publisher 
•	Contributor 
•	Date 
•	Type 
•	Format 
•	Identifier 
•	Source 
•	Language 
•	Relation 
•	Coverage 
•	Rights 
Dublin Core is currently typically embedded into HTML <META> tags in the <HEAD> section of HTML Web pages. In this way it is made available for collection and indexing by Web robots. In the future DC metadata is increasingly likely to be made available using the W3C’s Resource Description Framework [RDF], a generic metadata architecture for the Web.
3.10.1	Collection level description using Dublin Core
The Dublin Core was originally designed primarily for describing document-like objects (or DLOs) made available in a digital format on the Internet. There has however been some experimental use of the Dublin Core to describe other kinds of objects.
The Dublin Core Type Element Working Group [DCTYPE] is developing a list of resource types (a controlled vocabulary for use with the DC Type element). The proposed list currently includes the terms ‘collection’ and ‘dataset’, which could be used to refer to different kinds of collections. However, it should be noted that, at the time of writing, the inclusion of ‘collection’ in the list of types was still under discussion. 
3.10.2	Example
Here is an example of the use of Dublin Core to provide a simple description of the University of Bath Library OPAC:
Title:       University of Bath Library OPAC
Identifier:  telnet://library.bath.ac.uk/
Description: A searchable database of all the books and periodicals in
             the University of Bath Library
Publisher:   University of Bath
Type:        collection
Type:        catalogue.library
Language:    en-uk
Coverage:    Bath, UK
It should be noted that the ‘catalogue.library’ Type value is taken from the list proposed by the eLib Collection Description Working Group [ELIBCOLL]. 
Andy Powell, UKOLN
3.11	Web Collections
This section describes a number of mechanisms for grouping collections of Web-based resources. 
3.11.1	Simple linking
An early attempt to provide a mechanism for grouping Web resources was the HTML <LINK> element. For example:
<LINK NAME="next" HREF="slide-06.html">
<LINK NAME="previous" HREF="slide-04.html">
In this case the <LINK> element provides the address of the next and previous files. Although this information is readily available to the end user using normal <HREF> hypertext links, there is no mechanism for an application to automatically process this information. The <LINK> element provides a means of providing the information in a machine-understandable way.
The NCSA Mosaic for Windows browser makes use of the <LINK> element by providing buttons that can be used to move to the next and previous files. A document that has been split into several HTML pages could be described by using a series of ‘Next’ and ‘Previous’ LINK attributes. This information could be used to print the collection in a single operation, without having to display and then print each page individually.
Although the <LINK> element provides a simple mechanism for describing simple relationships between Web resources, alternative mechanisms are needed to describe more complex relationships.
3.11.2	Microsoft Web Collections
In March 1997 Microsoft submitted a proposal to the World Wide Web Consortium on Web Collections using XML. This proposal uses the Extensible Markup Language (XML) to provide a hierarchical structure for relationships between Web resources. This proposal defined the term collection as a grouping of metadata, a property as a description of metadata in the form of a name value pair, and a profile as a contract between the creator and reader of a Web Collection that specifies the properties that the reader can expect.
Anticipated applications of Web Collections included site maps, e-mail threading, scheduling, content labelling and distributed authoring. However, following feedback on the proposal Microsoft is no longer pursuing this proposal.
3.11.3	Channel Definition Format (CDF)
The Channel Definition Format (CDF) provides a mechanism to group Web resources together for various purposes. A Channel is defined as a set of documents or a grouping of content that can be ‘pushed’, pulled, or operated on as a unit. In today’s applications, the types of operations on a channel primarily involve automatic scheduled download for off-line use (‘smart pull’), or multicast delivery for later use. However, CDF may also provide the underlying mechanism to facilitate searching, indexing, profiling, filtering, and personalising content independent of the publishing mechanism. 
The Microsoft ‘Active Channel Technology Overview’ says: 
CDF (channel definition format) is an XML vocabulary, or XML-based data format, that can be used to organize a set of related Web documents into a logical hierarchy. CDF enables developers to describe the structure and logically present various structured views of their HTML-based sites. Individual Web pages can be described by a CDF file to specify a hierarchy of associated Web pages. Like HTML files, CDF files are structured text made up of various elements, each enclosed within opening and closing tags. CDF files provide an index of the resources available in the channel-a hierarchy of the channel’s Web pages-and can include a recommended schedule for when the channel should be updated on the user’s computer. Using CDF files, channel developers and end users can schedule content updates, deliver personalized, password-protected content, log page hits, set up Active Channel screen savers, and categorize content. A typical CDF file contains a top-level CHANNEL element to define the channel itself, along with ITEM elements to specify the actual contents of the channel. Subsequent occurrences of the CHANNEL element define subchannels and allow publishers to create a hierarchy for the channel. The TITLE and ABSTRACT elements can be used to describe the contents of each item or channel element. Publishers may also want to use the LOGO element to associate an image with each item in the channel, as well as with the channel itself. 
[MSCDF]
The current status of CDF is unknown. 
3.11.4	Meta Content Framework (MCF)
The Meta Content Framework [MCF] provides a system for representing a wide range of information about content. The content targeted includes Web pages, gopher and ftp files, desktop files, e-mail and structured (i.e., relational and object oriented) databases, etc. MCF is not intended to be an extension of markup languages such as HTML that can be used to hold embedded metadata. Instead it provides a format for holding the metadata externally to the content described. It is possible that metadata embedded in content will be extracted automatically by robots that use the MCF to represent the results of their activities. 
MCF can be used to describe collections of Web resources. MCF was originally developed by Apple Computers Inc., in association with a 3D Web-site visualisation tool known as ‘Hot Sauce’. 
The current status of MCF is unknown. 
3.11.5	Site maps
Web-sites often provide a ‘site map’, an overview of the main content on a site, as a simple method for end-users to gain access to resources that might otherwise be quite difficult to find. Site maps are typically written in HTML and, because there is no widespread agreement about how these maps should be structured, are not suitable for automatic processing by software (automated agents or Web robots). 
Recently there have been several attempts to provide structured site maps using the Resource Description Framework [RDF], including: 
•	WebResourceMap [WEBRESMAP] is an application of RDF used to provide a simple mapping for one or more Web sites. A WebResourceMap can describe metadata about the current state and changes in documents on a Web site. 
•	Mozilla, the open source version of Netscape Navigator, provides support for RDF-based sitemaps [MOZILLA]. 
3.11.6	WebDAV
The Internet Engineering Task Force (IETF) WebDAV Working Group [WEBDAV] are developing an architecture that will support distributed authoring and versioning across the Web in a way that is independent of particular client and server implementations. The functional requirements identified by the group operate on a ‘resource’, where a resource may be a ‘network data object or service that can be identified by a URI’ or a ‘collection’ of such objects. They define a collection as: 
A collection is a resource that contains other resources, either directly or by reference. 
... 
A collection is a resource that is a container for other resources, including other collections. A resource may belong to a collection either directly or by reference. If a resource belongs to a collection directly, name space operations like copy, move, and delete applied to the collection also apply to the resource. If a resource belongs to a collection by reference, name space operations applied to the collection affect only the reference, not the resource itself. 
[RFC2291]
The group also notes that: 
There are many instances where there is not a strong correlation between a URL hierarchy level and the notion of a collection. One example is a server in which the URL hierarchy level maps to a computational process which performs some resolution on the name. In this case, the contents of the URL hierarchy level can vary depending on the input to the computation, and the number of resources accessible via the computation can be very large. It does not make sense to implement a directory feature for such a name space. However, the utility of listing the contents of those URL hierarchy levels which do correspond to collections, such as the large number of HTTP servers which map their name space to a filesystem, argue for the inclusion of this capability, despite not being meaningful in all cases. If listing the contents of a URL hierarchy level does not makes sense for a particular URL, then a ‘405 Method Not Allowed’ status code could be issued. 
The ability to create collections to hold related resources supports management of a name space by packaging its members into small, related clusters. The utility of this capability is demonstrated by the broad implementation of directories in recent operating systems. The ability to create a collection also supports the creation of ‘Save As...’ dialog boxes with ‘New Level/Folder/Directory’ capability, common in many applications. 
[RFC2291]
Andy Powell, UKOLN
4	
Service Description
4.1	LDAP / X.500
X.500 [X500] is the name given to a series of standards produced by the ISO/ITU-T defining the protocols and information model for a global directory service. X.500 uses a distributed approach based on connected Directory System Agents (DSAs), each of which is a database containing information that is structured according to the X.500 information model. DSAs in the global directory service can exchange data using the Directory System Protocol (DSP). X.500 clients connect to DSAs using the Directory Access Protocol (DAP). 
The Lightweight Directory Access Protocol [LDAP], defined by the Internet community (in particular by the IETF ASID working group), was ‘designed to provide access to directories supporting the X.500 models, while not incurring the resource requirements of the X.500 Directory Access Protocol (DAP)’ [RFC1777]. LDAP is often implemented in ‘stand-alone’ mode, offering local access to an LDAP-only database without access to the wider X.500 directory. 
Both, X.500 and LDAP are primarily used to provide ‘white-pages’ services - information about people and organisations. However, the X.500 information model also defines object classes representing applications - allowing information to be stored in an X.500 or LDAP database describing network services. Such descriptions were originally designed to describe ISO applications (X.400, FTAM, X.500, etc.) and are not widely used. 
The ‘applicationEntity’ object class definition taken from the ‘The COSINE and Internet X.500 Schema’ [RFC1274] follows: 
applicationEntity OBJECT-CLASS 
SUBCLASS OF top 
MUST CONTAIN { 
    commonName, 
    presentationAddress
} 
MAY CONTAIN { 
    description, 
    localityName, 
    organizationName, 
    organizationalUnitName, 
    seeAlso, 
    supportedApplicationContext
}
Andy Powell, UKOLN
4.2	WASRV
The WASRV (Wide Area Service Location) working group [WASRV] was a proposed IETF WG that was tasked with defining an architecture for locating services on the Internet. The working group now appears to be dormant. However the following attributes were identified as being required for service location. 
Owner	The owner of the site. This would be more than just a domain name, but would be organisation name. 	
Content-Owner	In cases of Web hosting, the owner of the content is more useful than the Web site owner. This also would be an organisation name rather than an address. 	
Cost	Cost to use the service.	
Geographic-Location	This is different from distance metrics, but would be useful in some gateway searches. 	
Service-URL	If the service has a valid URL, put it here. 	
Service	If the service does not have a valid URL, the protocol would be specified here, along with the fully qualified domain name in Server-Name and port number in Server-Port. 	
Server-Name	FQDN of host server. 	
Server-Port	Port on host server. 	
Description	A short description of the service 	
Protocol-Version	The latest protocol version supported. 	
Availability	A specification of when the service is available (most often 7x24 but could be less for things like anonymous ftp) 	
Signature	A signature of the template for authentication, checkable by the certificate specified in Certificate. The Signature covers everything in the template (including the Certificate but the Signature attribute and should be the last attribute in the template. Stored in base64 encoding. 	
Certificate	A URL for downloading the certificate for checking a Signature attribute 	
Taken from message by Ryan Moats to WASRV mailing list. 
Andy Powell, UKOLN
4.3	WHOIS++ / ROADS
See section 3.8 for an introduction to WHOIS++ and ROADS and for an example of the use of the ROADS SERVICE template.
The ROADS SERVICE template [ROADSSERV] provides a mechanism for describing online services. The template is defined as follows:
Title	Complete title of the resource.		
URI	Identifier, usually an URL.		
Admin	For administrator of site.		
Owner	For the owner of the site.		
Sponsoring	For the site sponsor/s.		
Publisher	For the publisher.		
Description	Free text description of the service.		
Authentication	Authentication information, e.g. login and password details.		
Registration	Registration information if the resource is not available for general access.		
Charging-Policy	The charging mechanism in place. Including fee structure.		
Access-Policy	Policies for accessing the service.		
Access-Times	Time-ranges for mandatory or preferred access to the service.		
Keywords	Appropriate subject keywords which apply to the resource.		
Subject-Descriptor	A subject heading or classification number.		
Subject-Descriptor-Scheme	The scheme used in the Subject-Descriptor field.		
Short-Title	A shorter form of Title, e.g. an acronym.		
Alternative-Title	An alternative form of Title.		
Language	The language of the service.		
ISSN	International Standard Serial Number.		
Discussion	Free text discussion of possible discussion forums appropriate to the resource.		
Source	Information about the definitive version of a resource.		
Category	Type of resource		
Comments	Comments added by the ‘cataloguer’		
It is also worth noting that ROADS provides the ability to search across a number of local and remote ROADS services (using the WHOIS++ protocol). In order to configure cross-searching, ROADS uses the following attributes in a configuration file to describe each remote service:
URI 	The URI for the service	
Host-Name 	A host name...	
Host-Port 	...and port number	
Description 	A short description of the service	
Authentication-type 	Authentication requirements	
Authentication-data 	Authentication information, e.g. a password	
Andy Powell, UKOLN
4.4	Z39.50 Explain
The Z39.50 Explain Facility was introduced with Version 3 of the Z39.50 protocol, (Z39.50-1995). This facility comprises a protocol mechanism whereby the client is able to interrogate and retrieve information about the server and the databases on the server. The interrogation mechanism is achieved through a specific use of the Z39.50 Search service. The information is retrieved with the Z39.50 Present service using purpose-designed structured retrieval records. The Explain facility allows the client to obtain details of the server implementation, including the databases available for searching, search attribute sets, diagnostic sets, and supported record syntax. This data can be considered as metadata about the server and the services that the server offers.
A more detailed summary of the Z39.50 Explain Facility is available as part of a separate report: 
•	Analysis of the Z39.50 Profile for Access to Digital Collections and the Z39.50 Explain Service

References
BUBL515	BUBL LINK / 5:15
<http://bubl.ac.uk/link/five/>	
CAIRNS 	CAIRNS: Co-operative Academic Information Retrieval Network for Scotland 
<http://bubl.ac.uk/org/scurl/docs/cairns1.htm> 	
DC 	The Dublin Core Metadata Element Set home page 
<http://purl.org/dc/> 	
DCTYPE 	Dublin Core Type Element Working Group 
<http://purl.org/dc/groups/type.htm> 	
EAD 	Encoded Archival Description - Official Web Site 
<http://lcweb.loc.gov/ead/> 	
ELIB	eLib - Electronic Libraries Programme
<http://www.ukoln.ac.uk/services/elib/>	
ELIBCOLL 	Collection Description Working Group 
<http://www.ukoln.ac.uk/metadata/cld/> 	
GILS 	GILS.ORG 
<http://www.gils.org/> 	
GILSPROF	Application Profile for the Government Information Locator Service (GILS) - Version 2
<http://www.usgs.gov/public/gils/prof_v2.html>	
IAFA 	<http://info.webcrawler.com/mak/projects/iafa/> 	
ISADG 	ISAD(G): General International Standard Archival Description 
<http://data1.archives.ca/ica/cds/isad(g)e.html> 	
LDAP 	An LDAP Roadmap & FAQ 
<http://www.kingsmountain.com/ldapRoadmap.shtml> 	
MCF 	Meta Content Framework Using XML 
<http://www.textuality.com/mcf/NOTE-MCF-XML.html> 	
MODELS	MODELS: MOving to Distributed Environments for Library Services
<http://www.ukoln.ac.uk/dlis/models/>	
MOZILLA 	<http://www.hotwired.com/webmonkey/98/18/index3a.html> 	
MSCDF 	Active Channel Technology Overview 
<http://msdn.microsoft.com/workshop/delivery/channel/overview/overview.asp> 	
RDF 	Resource Description Framework (RDF) Model and Syntax Specification 
<http://www.w3.org/TR/REC-rdf-syntax/> 	
		
RFC1274 	The COSINE and Internet X.500 Schema 
RFC-1274 
<http://andrew2.andrew.cmu.edu/rfc/rfc1274.html> 	
RFC1777 	Lightweight Directory Access Protocol 
RFC-1777 
<http://www.hensa.ac.uk/ftp/mirrors/ftp.isi.edu/in-notes/rfc1777.txt> 	
RFC1835 	Architecture of the WHOIS++ service 
RFC-1835 
<http://www.hensa.ac.uk/ftp/mirrors/ftp.isi.edu/in-notes/rfc1835.txt> 	
RFC1914 	How to Interact with a Whois++ Mesh 
RFC-1914 
<http://www.hensa.ac.uk/ftp/mirrors/ftp.isi.edu/in-notes/rfc1914.txt> 	
RFC2291 	Requirements for a Distributed Authoring and Versioning Protocol for the World Wide Web 
RFC-2291 
<http://www.hensa.ac.uk/ftp/mirrors/ftp.isi.edu/in-notes/rfc2291.txt> 	
ROADS 	ROADS: Resource Organisation And Discovery in Subject-based services 
<http://www.ilrt.bris.ac.uk/roads/> 	
ROADSCOLL 	ROADS (experimental) COLLECTION Template Type 
<http://www.ukoln.ac.uk/metadata/roads/templates/collection.html> 	
ROADSSERV 	ROADS SERVICE Template Type 
<http://www.ukoln.ac.uk/metadata/roads/templates/service.html> 	
SCURL	Scottish Confederation of University and Research Libraries
<http://bubl.ac.uk/org/scurl/>	
W3CTERM 	Web Characterization Terminology & Definitions sheet 
W3C Working Draft 24-May-1999 
<http://www.w3.org/1999/05/WCA-terms/> 	
WASRV 	IETF WASRV (proposed) Working Group Homepage 
<http://www.bell-labs.com/mailing-lists/wasrv/> 	
WEBDAV 	IETF WEBDAV Working Group 
<http://www.ics.uci.edu/pub/ietf/webdav/> 	
WEBRESMAP 	WebResourceMap: a simple website mapping RDF sample - v0.1 <http://www.edu.uni-klu.ac.at/~jmodre/rdf/WebResourceMap.html> 	
WHOISTEMP 	WHOIS++ Templates - Internet Draft (expired) 
draft-ietf-asid-whois-schema-03.txt 	
X500 	NEXOR - X.500 and Internet Directories 
<http://www.nexor.com/info/directory.htm> 	

Acknowledgements
Several authors have contributed to this study. This has been acknowledged at the end of individual sections. The list of contributors includes: 
Rob Bull (CrossNet Ltd), Martin Fisk (Aurora Information Technology), Martin Hamilton (Loughborough University), Brian Kelly (UKOLN), Ray Lester (Natural History Museum), Ann Matheson (National Library of Scotland), Patricia Methven (King’s College London), Jim Murray (National Library of Scotland), Dennis Nicholoson (Strathclyde University), Andy Powell (UKOLN), Rosemary Russell (UKOLN). 
Much of the material in 3.7 is taken from the GILS section of the DESIRE report, ‘A review of metadata: a survey of current resource description formats’ (see <http://www.ukoln.ac.uk/metadata/desire/overview/>) and the GILS FAQ (see <http://www.usgs.gov/gils/faq.html>).
Material in 3.10 is taken from the Dublin Core home page, maintained by OCLC, <http://purl.org/dc/>.