IBM put its weight behind the Linux open source operating system (OS) on Wednesday, when it announced that Linux supplier Red Hat would provide support for the OS running on its PCs and servers.

Last year, Big Blue released a Linux version of its DB2 database and it had been widely expected to endorse the OS more fully. But, the supplier surprised some observers by saying it would support the Linux not only on its servers, but also on its desktops and laptops.

Under an agreement with Red Hat, both companies will work together to optimise Red Hat Linux to run on IBM machines. The focus will mainly be on developing drivers for IBM specific hardware.

Big Blue will initially ship Red Hat Linux on its Netfinity line of servers, but will also support customers under its Server Start up programme. This entitles users with Windows NT, OS/2, Santa Cruz Operation?s (SCO) Unixware and Novell?s Netware machines to 90 days of free OS support.

Momentum has been gathering behind Linux over recent months. Last year, several major software vendors, including Oracle and Informix, announced they were porting their products to the OS, but this year, it appears to be the turn of the hardware vendors.

Three weeks ago, Hewlett Packard announced that its Intel based NetServer systems would support Red Hat Linux, while Dell said it would certify certain of its servers and workstations to run the OS earlier this month. Compaq is also widely rumoured to be about to jump on the bandwagon.

But analysts were quick to point out that IBM was facing a conflict of interests despite its vocal support of Linux.

Late last year, the company teamed with SCO to develop a common 64bit and 32bit Unix OS, codenamed Monterey, which would merge UnixWare and IBM's own AIX technologies. Big Blue also has other server OSs to support, including OS/400, OS/2 and Windows NT.

Dan Kusnetzky, an analyst with market research firm IDC, said: "It?s in IBM?s interest to support their own Unix first. How they are going to position [Linux], is really a challenge. My sense is that it is putting its toe in the water to see if nothing will bite it."

He added that Linux accounted for more than 17 per cent of all server OSs sold in 1998, although total the revenues generated were a mere $33 million.