Index+ has powerful native free-text searching, but in a network age it is also important to have systems that enable groups of organisations and individuals in dispersed locations to work together or get access to each other's content.

A series of Index+ tools allow IT systems to search and retrieve information from databases of different types in different geographical locations and belonging to different organisations within an integrated framework. This means that for the individual user the experience is of operating within one coherent system.

These tools include Z39.50, OAI or SRU/SRW servers to provide access to Index+ systems from outside and further tools for searching across external databases, using Z39.50 or SRW/U, or for harvesting metadata using OAI-PMH. Dublin Core or more elaborate metadata schemata are supported.

All the tools can be combined in the Index+ Bridge, which provides a broker for accessing a variety of distributed database systems, together with a user interface that facilitates the management of the search process.

The Index+ tools available for remote searching and harvesting are:

Z39.50 Gateway

Z39.50 is an international standard information retrieval protocol. The Index+ Z39.50 Gateway allows Z39.50 client software to search in and retrieve data from Index+ and other compliant databases over the internet. A number of resources can be made available through the same interface - essential for the development of effective library and resource management services on the network.

System Simulation's early work on projects such as Aquarelle, CIMI, Van Eyck, SCRAN and ADAM helped to extend the use of Z39.50 into the cultural heritage sector.

OAI Gateway

The OAI-Protocol for Metadata Harvesting (OAI-PMH) defines a mechanism, based on HTTP and XML, for harvesting records with metadata that describe content and for allowing these metadata from diverse sources to be gathered together in a single database as the basis for developing further services. The metadata harvested can be in any format agreed by the relevant community. On the other side, of course, the protocol also gives data providers the means to make their metadata available.

SOAPIX

SOAPIX is the Index+ SOAP server. It allows access to any Index+ database via SOAP.

SOAPIX is currently in use at the V&A, the Geffrye Museum, the British Museum and ESCALA.

Index+ Bridge (aka Broker)

The Index+ Bridge is an information broker which allows Index+ systems to search and retrieve information from remote databases. This has many applications:

• Search forms can allow optional searching across other datasets, for example, an Index+ search form could have a set of check-boxes each of which broadens the search to a specific repository which might be held remotely.
• Bibliographic and other references can be made 'real' so that clicking on the reference will retrieve the item from the remote database to the local database.
• Index+ client software can be used to front non-Index+ databases.
• Datasets which cannot be held in a single repository for organisational or policy reasons can be presented together.

The Web allows some of these facilities, but only managed at the user's browser. Since the Index+ Bridge manages these database accesses itself, the facilities can be presented to the user with all the power of Index+'s authoring and presentation capabilities. It is also not restricted to use in web browsers, but can be used in any Index+ client software.

The Index+ Bridge is organised as a set of 'channels', each channel managing a different kind of dialogue or protocol. Currently we offer a Z39.50 channel, implementing the ISO standard for distributed searching and retrieval, a new SRU/SRW channel which enhances certain features of Z39.50 searching, an OAI-PMH channel for harvesting metadata from distributed sites and a 'shell' channel which allows for the easy and flexible prototyping of other bridging possibilities.