Many corporate IT departments have piloted the use of open source software within their own departments successfully, especially the Linux operating system. Some are now extending its use across the whole enterprise.

However, many finance departments have become heavy users of Microsoft software, with accounting systems, financial consolidation and corporate performance management systems running on Microsoft Windows servers, while their desktop clients and spreadsheets run on Microsoft's Windows desktop operating system.

For most organisations, this is not a problem as most applications that move to Linux come from another version of the Unix operating system. Dennis Keeling, director of the Business Application Software Developers Association, reports that members who have accounting applications and databases that run on other flavours of Unix have found it easy to port them across to Linux.

Users can still access the accounting system from their desktop using their existing Windows 'fat client' software as they use standard protocols to communicate with the server software. Alternatively, they can move across to a Linux desktop environment and use the accounting system's web interface through a browser. However, Keeling warns that it is less user-friendly than the traditional fat client. "It is fine for enquiries, but not for data entry."

He points out that migration to Linux is only happening in mid-size corporates. "We don't see it in the small and medium sector. It isn't an issue for Sage, but companies such as Oracle and SAP are being asked for it all the time."

IT departments that want to migrate to Linux can quite happily leave the accounting systems on Windows. Graham Titterington, an analyst at Ovum, points out that most companies have a mix of platforms. "There may be some savings in the licensing terms and by having only one skillset, but those arguments are exaggerated by the respective camps, " he says. "There is no real reason why they have to have a single platform across the entire organisations."

Titterington believes that Linux might be an option for any organisation that is still running an old version of Windows. If its support is coming to an end, they would have to upgrade anyway. Interoperability between a Window-based accounting system and other business applications running on Linux shouldn't be a problem because most application software uses standard communication protocols. "As long as the organisation has a reliable financial application and the systems it talks to are stable, it doesn't matter if the two applications are running on different platforms," he says.

The Windows and Linux camps may be slugging it out for market share, but both support the latest standards and can co-exist quite comfortably. "Having the best tool for the job is more important than the operating system," Titterington concludes. "If people are already on Windows 2003 they are not likely to move in the near future. If the accounting system is working fine, then I can't see a lot of reason why anybody would want to change. They should leave well alone."