SCO has responded to Novell's demands to prove that its Unix code was copied into Linux by offering to show the 'evidence' behind its case.

Looking to dispel doubts about the merits of its $1bn suit against IBM, SCO has claimed it will show how it believes Linux developers and users have illegally used its Unix code.

The company will show source code from its Unix system V operating system and kernel alongside matching code from the Linux version 2 kernel.

The move comes just days after Novell's chief executive and chairman, Jack Messman, strongly criticised SCO's claims to own Unix patents and copyright.

Messman demanded that SCO provide details to back up its claim that SCO intellectual property had been added to Linux without its consent.

Press, analysts and customers will all be offered a viewing, but only after signing a non-disclosure agreement with SCO and proving that they can adhere to it, the firm said.

"June is show and tell time," said Darl McBride, president and chief executive of The SCO Group.

"Everyone has been clamouring for the code and we will show hundreds of lines that are just the tip of the iceberg," he said.

SCO said its evidence comes from three separate groups it commissioned to look for similarities in its Unix source code and the Linux kernel.

The findings of these groups are the basis for SCO's case against IBM, which it accuses of breach of contract, misappropriation of trade secrets and promotion of unfair competition.

The case could also be the basis for similar claims against other Linux developers and customers.

McBride warned that SCO may also take action to refute Novell's claims. "We will not rule out subsequent enforcement on the basis of copyright," he said.

And he revealed that Novell senior executive Chris Stone failed to attend a meeting to view SCO's 'evidence' scheduled the day before Messman's attack.

In response, Novell said the meeting would have involved Stone signing a non-disclosure agreement, which was unacceptable.

Analysts said SCO's decision was an attempt to counter a largely negative reaction against it since its warning that Linux users may be liable.

"This is a PR gambit," said George Weiss, vice president and research director at Gartner. "SCO has done a good job clarifying what it is trying to do but until we get specifics it is difficult to predict the conclusion," he added.

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