Tait Radio Communications is a global leader in designing and delivering radio solutions which are the right fit for a variety of industries including public safety agencies, government services, utilities and urban transport providers. Corporate services are based in New Zealand, and Tait has a network of worldwide offices and distributors.

As part of a wider strategy to develop an advanced intranet, Tait asked Flax to install a search engine to index a wide variety of content types. Frank Gebhardt, ICT Manager at Tait, said “We considered a variety of commercial, closed source search engines including search appliances, but chose Flax due to the flexibility of their open source solution and the way it allowed us to index millions of documents at a much lower cost.”

The Flax system builds an index of twelve million documents across Tait's file systems, in formats including Microsoft Office, Open Office, Adobe PDF and plain text. The system automatically re-indexes any documents that change (or new ones that appear), removing the need for a regular complete rebuild of the index, which is kept up to date on a daily basis.

The search engine is powered by Xapian, a highly scalable open source search library originally developed in Cambridge, UK as a foundation for a half-billion-page web search engine and featuring Bayesian probabilistic ranking of results. Flax developed a high performance, multi-threaded file system crawler and custom search front end to augment this software.

One of Tait's key requirements for the search engine was that results should only be shown to those with the appropriate rights to view them. The search engine thus captures security information for each document indexed, and matches this against the rights of the logged-in user. UNIX file permissions and access control lists (ACLs) are indexed and a central LDAP server used for retrieving user information.

Amongst other features provided by the Flax solution are faceted search, spelling correction and ranking of results by date or by relevance. The system also allows users to 'tag' documents in search results so that (for example) the most up-to-date of a series of specifications can easily be identified. Searches may then be carried out in future using the tags as a filter. New or updated tags are visible to searches within a few seconds.

The search engine runs on a single server that handles all indexing, searching and tagging operations, and is available globally to all Tait staff.

The new system has been well received by Tait staff: Frank Gebhardt says “Our staff are very excited about the new search engine. ‘I have been waiting for this a long time.’ is the most common phrase I get to hear, along with “I like it, it does the job!”

Charlie Hull of Flax said “The open source search engine provides powerful features and ease of integration with existing systems – this allows for a process of iterative design, so users in the corporate setting will have a tool that works for them, rather than being forced into someone else's idea of what may be useful.”