Companies hoping to cut costs by moving from Windows to Linux on the desktop will find that in most cases the open source operating system will fail to save them money, analyst Gartner has warned.

It said that although Linux has had success at reducing IT costs for servers the same is not true of desktops.

Gartner vice president and fellow, David Smith, said many servers are dedicated to running a single application, which makes it relatively easy for enterprises to replace specific servers with Linux.

But the environment for Linux on the desktop is significantly different, he warned. "Knowledge workers use PCs to run diverse combinations of applications.

"For those users, migration costs will be very high because all Windows applications must be replaced or rewritten," he said.

Migrating PC desktops to Linux makes sense only in a very narrow range of situations where there are relatively few applications and those are fixed-function or low-function, such as data entry, call centre or bank teller/platform automation, Gartner said.

And the organisation warned that before any migration plan is implemented enterprises must gain a full understanding of the total cost of ownership (TCO).

Michael Silver, vice president and research director at Gartner, said the cost of the PC and client operating system represented only a small part - generally 20 per cent to 30 per cent - of the overall TCO.

Other costs, such as labour, training and external services, must also be considered. Companies should also compare the benefits of a move to Linux with an upgrade to a newer version of Windows.

"The TCO of Windows 95 is relatively high, and increasing, because support from Microsoft has been eliminated and support from independent software vendors and other third parties continues to wane," said Silver.

"Therefore, enterprises running Windows 95 will likely see more benefits by a move to Linux than will enterprises using Windows 2000 or Windows XP.

"Windows 2000 and Windows XP include more modern technology than Window 95 and are generally more stable and incur lower costs."