2   Background

Greenstone is a suite of software for building and distributing digital library collections [4]. It is not a digital library but a tool for building digital libraries. It provides a flexible way of organizing information and publishing it on the Internet in the form of a fully-searchable, metadata-driven digital library. Using it, a rich set of different types of collections can be formed that reflect the nature of the source documents and metadata available.

In extending Greenstone for institutional repository use our aim was to develop a software solution that transcends the limitations imposed by current solutions specifically targeted towards institutional repositories, without triggering the high startup costs of shifting to a highly generalized framework.

We want to enable librarians to turn any Greenstone collection into a repository into which new items and metadata can be deposited by authorized personnel through an ordinary web interface. But different Greenstone collections have different metadata sets, and there is no restriction on how extensive—or minimalist—such metadata can be. So when metadata is entered through a sequence of web pages, the content of these pages, the number of pages in the sequence, and the metadata items that each one requests must all be customizable. For one collection a single web form may suffice; another may require a long sequence of different forms. When the depositing user goes back to an earlier to step to correct a metadata entry this variable amount of data—which is entirely dependent on the metadata set in use—must be remembered by the web browser.

We use the following notion of “generalized institutional repository”:

•  The digital library collection can use any metadata set.

•  Depositing an item can involve any number of steps.

•  The stages involved in depositing an item can be designed individually.

•  Flexible workflow.

Depending on institutional procedures librarians may have roles such as 'reviewer', 'approver' or 'editor' for deposited items [1].