SCO CEO Darl McBride's people say it's a check he really wants to write.

Starting Monday afternoon and quickly turning into a tsunami, MyDoom, a mass mailer that requires recipients to open a zip file, has clogged e-mail servers with as many as 1,000 junk e-mails a minute, bringing systems to their knees and slowing down the Internet generally. It impacted Windows machines and hopped on the Kazaa P2P file-sharing network. Three days after it got into the wild, it had done an estimated $22.6 billion and rising in damage. It may grow to be more viral than last year's notorious SoBig virus that is calculated to have done $37 billion worth of damage.

MyDoom, aka Novarg and Shimg, singles out SCO and threatens to unleash a massive Distributed Denial of Service on SCO's Web site this Sunday, Super Bowl Sunday. Either the SCO attack is MyDoom's real purpose, or, it's perverse justification.

A copycat MyDoom.b cropped up on Wednesday aimed at taking out Microsoft's Web site on February 3 as well as SCO's. MyDoom.b is a particularly nasty piece of work. It prevents infected machines from reaching computer support and anti-virus sites like Network Associates and Symantec. It also prevents access to Office and Windows update sites.

Experts believe both viruses may come from the same source. MyDoom.b reportedly contains the message, "I'm just doing my job, nothing personal, sorry." There was talk about MyDoom resembling Russian spam and machines infected with MyDoom tripping off MyDoom.b.

mi2g Ltd in the UK says it may be a new generation of viruses and may have a bigger target than either SCO or Microsoft like online transaction fraud or mass identity theft.

SCO has been hit with several DDoS attacks since it sued IBM for allegedly putting SCO's Unix code in Linux. McBride, however, labeling MyDoom "criminal," said in a prepared statement that MyDoom is "different and much more troubling, since it harms not just our company, but also damages the systems and productivity of a large number of other companies and organizations around the world.

SCO's initial statement Tuesday stopped short of blaming the Linux community for MyDoom as SCO has blamed it for the DDoS attacks before. Instead, SCO said, "We do not know the origins or reasons for this attack, although we have our suspicions."

But by the time McBride was being interviewed on CNBC Wednesday he labeled the virus "apparently" the work of a "radical element of the Linux community." And independent industry watchers started predicting that open source could easily suffer a backlash because of the association between viruses and Linux. They speculated that the government could clamp down on the Internet because of the geopolitics of such stunts.

SCO is also likely to garner some sympathy from the corporate world because of MyDoom. It doesn't help the Linux/open source cause that boobs with open source convictions publicly rejoiced in the virus.

Open source leader Bruce Perens, presuming that SCO has the necessary skills, claimed either a spammer or SCO itself concocted MyDoom.

Perens wrote an open letter saying, "SCO...has a reason to defame us, as part of their stock-kiting scheme. We have assembled ample evidence that they have lied under oath in court. Such a company would not balk at attacking their own site in order to paint their opponents in a bad light. Thus, it is likely that this virus has been assembled for the purpose of defaming the Linux developers by spammers, SCO or others."

SCO said it was working with law enforcement including the Secret Service and FBI and said anyone with information on the identity of the perpetrator should contact the FBI.

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