San Francisco: Corporate computer maker Sun Microsystems on March 8 filed a $ 1 billion-plus anti-trust suit against Microsoft, adding to the ongoing anti-trust battles facing the Seattle software giant.

In the suit, Sun, which makes powerful corporate-class computers and software, said it will ask to be compensated for "economic harm" caused by Microsoft, and will ask for tripling of those damages, as allowed by US antitrust laws.

The lawsuit charges Microsoft abused Java, a Sun-created software language that the two companies warred over four and a half years ago. Java is software code that works on a range of machines, and it allows these various computers to view animation and graphics over the Internet.

Sun accuses Microsoft is using its market clout to strangle Java by excluding the software from its recent Windows XP release and other software packages. The lawsuit also charges Microsoft with distributing its own version of Java.

In January 2001, Sun and Microsoft had settled an earlier battle over Java, which involved Microsoft's alleged breach of the Sun Java license.

This lawsuit goes beyond that feud, alleging that Microsoft is now using its dominance to kill off Java and discourage developers from using the language.

The lawsuit asks for a preliminary injunction forcing Microsoft to distribute Sun's Java with Microsoft's software, and to cease the distribution of a Microsoft version of the code.

A Sun spokeswoman said the damages could top $ 1 billion. Sun's lawyer, Michael Morris, would not peg a specific number on those damages, but said monetary damages could be "substantial".

The lawsuit drew a familiar response from Microsoft, which has publicly argued that such litigation is a way for competitors to cripple the company.

Microsoft currently enjoys a nearly complete lock on the world's software market, with its Windows operating system found on more than 90 per cent of desktop computers.