Sun Microsystem's launch of Solaris 8 on Wednesday struck a double blow against rival operating systems, Linux and Windows 2000.
Not only will Solaris source and binary code for systems of less than eight processors be given away free, but it will also be first off the starting block in the race against Microsoft's contender, which is due to be unveiled in February.
Solaris 8, which runs on both the Sparc and Intel platforms, is aimed at Internet users and Internet Service Providers.
Jonathan Mills, Sun UK's software product marketing manager, said: "Microsoft slipped past our launch date. Windows 2000 is trying to position itself as more upmarket, but our heartland is populated by businesses that can't take that risk."
He added that Solaris 8 would target enterprises wanting to "get into the Internet with an operating system that is low risk and secure".
On the question of Solaris 8 stealing Linux users, Mills claimed: "We are widening the palatability of Solaris at the lower and smaller end and Linux is used to develop small scale systems, but Linux and Solaris are helping to establish Unix in the market place."
He added: "You can run Linux applications on Solaris. We like Linux."
Rakesh Kumar, programme director for enterprise datacentre strategies at the Meta Group, said: "The fact it is free is interesting and shows Sun has been feeling the pinch from Linux. Sun is making sure there is no exposure at the low end environment."
He added: "Bill Gates would love to think that Windows is in the same arena as Solaris 8, and people will make comparisons, but Windows can't hack it. It will take two to three years to mature."
Solaris 8 also comes with a bundle of development tools, including Sun's free Staroffice application suite, which competes with Microsoft Office, its iPlanet Webtop software, iPlanet application server, Apache Web server, and Oracle's 8i database.
Mills said the upgrade also included functionality to ensure availability and to make downtime easier to plan. A network cache accelerator provided a fourfold performance boost in serving Web pages, while a live upgrade enabled users to install and reconfigure new versions of the operating system while the current one was still running.
Solaris 8 is backwards compatible and costs £54 per CD-Rom.
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