Packaged software king Microsoft and cloud computing prince Salesforce.com are duelling in US courts, with each accusing the other of violating its patented technology.
The legal battle comes as Microsoft strives to adapt to a trend toward programs being offered as services in the Internet "cloud" instead of being purchased and then installed and maintained on people's computers.
Microsoft built its fortune selling software such as Office, Outlook, and Windows while San Francisco-based Salesforce has become a prospering poster child for a new era of cloud computing.
Microsoft has introduced an Azure cloud computing platform for its "live services" offered on the Internet.
Salesforce on Thursday filed a patent-infringement lawsuit against Microsoft in apparent retaliation for similar litigation that the US technology colossus filed against Salesforce in May.
"It's a normal response," said analyst Rob Enderle of Enderle Group in Silicon Valley. "Salesforce is trying to create some balance so there is reason for Microsoft to come to the table and negotiate."
Microsoft's legal filing accuses Salesforce of infringing on nine patents.
"Defendant's infringement of the Microsoft patents-in-suit is willful and deliberate, entitling Microsoft to enhanced damages and reasonable attorney fees and costs," the company said in court documents.
In a similarly worded counter-suit filed Thursday, Salesforce lawyers accuse Microsoft of violating five of the firm's patents in offerings including Windows Live online services and its new Windows 7 operating system.
Both suits demand jury trials and cash damages.
"Usually, the larger, better funded company wins in this kind of battle," Enderle said. "Microsoft is saying that Salesforce is using its core patents and they tend to protect those vigorously."
Microsoft has a much more extensive portfolio of patents to bring to a legal fight over intellectual property, according to the analyst.
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