When Google launches the full version of its desktop search tool on Monday, it will include the ability to search the full text of Adobe PDF files and the metadata of multimedia files.

Until now, only version available was a beta that could only index the names of PDF and multimedia files, such as image, music and video files.

As well as the text in PDFs, the new version can search metadata of multimedia files, such as song and artist names in music files.

Google says that the full version, as is customary for all software, will continue to be regularly enhanced.

"We've taken the product out of beta because now we have all the file types and features that were high on the list of user requests," Bhatla says, adding that by removing the beta tag, Google is hoping more users will feel encouraged to download and install the product.

Competition is fierce among providers of tools that let users index and retrieve information found on their PCs, a task for which few products existed until recently. Desktop search is viewed as an important area of the overall search engine market, because increasingly users expect to be able to find information on their PCs in the same way they find information on the internet.

Although it isn't clear yet how search engine vendors will make money from these tools, most of which are free, it is generally agreed that a user who becomes loyal to a desktop search product is highly likely to extend that loyalty to the tool maker's internet search engine.

In recent years, the market for online ads that search engines serve up with their query results has exploded. However, a big challenge for search engine vendors is to find ways to foster loyalty among their users. Studies have shown users feel little attachment to particular engines.

Google introduced its desktop product in October of last year, joining Lycos and several smaller, niche players, such as Copernic Technologies, X1 Technologies and Blinkx, which already had desktop search tools available.

However, Google beat big search engine providers such as Microsoft, Ask Jeeves, Yahoo and AOL, all of which subsequently released their own test versions of desktop search tools. Yahoo partnered with X1 and AOL with Copernic for their respective desktop search entries.

Other improvements in the Google desktop tool, which is free, include support for the Mozilla Foundation's Firefox browser and Thunderbird email application and for AOL's Netscape browser and email application. Previously, the product supported only Microsoft's Internet Explorer browser and Outlook and Outlook Express email applications.