EDEN: a web-based model for electronic document exchange.

ABSTRACT

The advantages of Web-based document exchange between libraries are just beginning to be systematically explored. This article focuses on general considerations in the development of a Web-based model for electronic document exchange (EDE) in the context of the OpenILL Cooperative's EDEN project. These include an overview of the existing document delivery standard (GEDI) and its relationship to emerging models and a discussion of factors being considered in the development of a Web-based protocol, including document exchange format, application event sequencing, metadata, and security.

INTRODUCTION

The spread of the Web and its associated hypertext transfer protocol (HTTP) have all but eliminated the technical difficulties associated with moving computer files from one place to another. For a variety of reasons, however, library document delivery networks do not currently take full advantage of HTTP, relying instead on the earlier file transfer protocol (FTP) for the interchange of documents between sites. HTTP, when it is used at all, tends to be employed in the final stage of the document delivery process, delivering content to end-users.

The advantages of Web-based document delivery to end-users have been widely discussed and documented (Schnell, 2000; Sayeed, Murray, & Wheeler, 2001). The advantages of Web-based document exchange between libraries are just beginning to be systematically explored. Atlas Systems has announced that its Odyssey document delivery software is being designed around a new open, Web-based protocol. And the OpenILL Cooperative's EDEN (Electronic Document Exchange Network) project is focused on building an open source implementation of Web-based document exchange to work in conjunction with its open source interlibrary loan (ILL) management system. At the time of writing, neither project has yet published its protocol specification (although both may now be available).

This article focuses on general considerations in the development of a Web-based model for electronic document exchange (EDE). These include an overview of the existing document delivery standard (GEDI) and its relationship to emerging models and a discussion of factors being considered in the development of a testbed for the EDEN project, including document exchange format, application event sequencing, metadata, and security.

The term "document delivery" can be used to cover a wide range of activities. In this context I am using the phrase "document delivery network" to refer to a group of libraries capable of exchanging documents over the Internet and capable of receiving documents from commercial suppliers. It makes sense as well to limit the concept of "document delivery" to documents that are not directly accessible to end-users in print or electronically; typically this includes documents neither owned nor licensed by the user's library or documents that are unavailable on the public Web.

EXISTING TECHNOLOGIES AND STANDARDS

Library document delivery networks typically rely on the use of specialized software created specifically for the purpose of streamlining the digitization and Internet transmission of print documents. Infotrieve's Ariel software (formerly developed by the Research Libraries Group [RLG]) is by far the dominant player in this niche, and it is sometimes referred to as the "de facto standard" for document exchange between libraries (Franke-Webb, 2001). Consequently, it is common to define a "document delivery network" as a set of distributed workstations intercommunicating via Ariel or Ariel-type software.

A de facto standard is of course not a formal standard. Part of the reason that libraries have been slow to embrace a Web-based model for electronic document exchange has been that the de facto standard, Ariel, is built around a formal standard, GEDI (Generic Electronic Document Interchange, ISO 17933), that was finalized in the very early days of the Web. The first version of the GEDI standard dates from 1991, when the Web consisted of a handful of experimental nodes (Berners-Lee et al., 1994). Consequently, HTTP would have been on nobody's radar screen when the standard was being worked out. There have been two subsequent versions of GEDI, in 1995 and 2000. The 2000 version permitted an alternate transfer protocol (email) and alternate file formats (PDF and JFIF [JPEG]). HTTP was not mentioned (International Organization for Standardization, 2000).

GEDI specified a standard file transfer protocol (initially FTAM, later FTP), a standard file interchange format (TIFF), and a standard format for metadata (the GEDI document header). Metadata was included as an SGML header prepended to the TIFF document, containing origin and destination information, document interchange format, and document description.

The GEDI standard was created to solve a particular problem: achieving interoperability between document delivery networks. In the late 1980s and early 1990s a number of separate agencies in Europe and North America were developing systems for electronic document exchange. As the number of agencies and networks increased, it was recognized that the development of incompatible systems would create a "Tower of Babel" impeding document exchange between disparate document delivery networks. These disparate networks were conceptualized as "domains" in the original GEDI Recommendation (Braid, 1994). GEDI was…