Greenstone is a suite of software for building and distributing digital library collections. It provides a new way of organizing information and publishing it on the Internet or on CD-ROM. A suite of software for building and distributing digital library collections.

Greenstone constructs full-text indexes from the document text-that is, indexes that enable searching on any words in the full text of the document. Indexes can be searched for particular words, combinations of words, or phrases, and results are ordered according to how relevant they are to the query.

In most collections, descriptive data such as author, title, date, keywords, and so on, is associated with each document. This information is called metadata. Many document collections also contain full-text indexes of certain kinds of metadata. For example, many collections have a searchable index of document titles.

Users can browse interactively around lists, and hierarchical structures, that are generated from the metadata that is associated with each document in the collection. Metadata forms the raw material for browsing. It must be provided explicitly or be derivable automatically from the documents themselves. Different collections offer different searching and browsing facilities. Indexes for both searching and browsing are constructed during a "building" process, according to information in a collection configuration file.

Greenstone creates all index structures automatically from the documents and suppporting files: nothing is done manually. If new documents in the same format become available, they can be merged into the collection automatically. Indeed, for many collections this is done by processes that awake regularly, scout for new material, and rebuild the indexes-all without manual intervention.

Document formats
Source documents come in a variety of formats, and are converted into a standard XML form for indexing by "plugins." Plugins distributed with Greenstone process plain text, HTML, WORD and PDF documents, and Usenet and E-mail messages. New ones can be written for different document types (to do this you need to study the Greenstone Digital Library Developer's Guide). To build browsing structures from metadata, an analogous scheme of "classifiers" is used. These create browsing indexes of various kinds: scrollable lists, alphabetic selectors, dates, and arbitrary hierarchies. Again, Greenstone programmers can create new browsing structures.

Multimedia and multilingual documents
Collections can contain text, pictures, audio and video. Non-textual material is either linked into the textual documents or accompanied by textual descriptions (such as figure captions) to allow full-text searching and browsing.

Unicode, which is a standard scheme for representing the character sets used in the world's languages, is used throughout Greenstone. This allows any language to be processed and displayed in a consistent manner. Collections have been built containing Arabic, Chinese, English, French, M 0 1ori and Spanish. Multilingual collections embody automatic language recognition, and the interface is available in all the above languages (and more).

The Greenstone software is designed to be easy to use. Web-based and CD-ROM collections have interfaces that are identical. Installing the Greenstone software from CD-ROM on any Windows or Linux computer is very easy indeed; a standard installation setup program is used in conjunction with pre-compiled binaries. A collection can be used locally on the computer where it is installed; also, if this computer is connected to a network, the software automatically and transparently allows all other computers on the network to access the same collection.

The next section describes how to install a Greenstone CD-ROM. Then we look at the searching and browsing facilities offered by a typical Greenstone collection, the "Demo" collection that is supplied with the Greenstone software. Other collections offer similar facilities; if you can use one, you can use them all. The following section explains how to customize the interface for your own requirements using the Preferences page.

The license of this software is Free, you can free download and free use this information management software.