Cary Jardin alleges that Stuart Frost "used and incorpoarted" Jardin's patented intellectual property in DATAllegro products, according to a complaint (35-page PDF) filed Tuesday in U.S. District Court in San Diego.

The complaint says Frost was CEO of Jardin's XPrime "for a brief period of time in 2003," where he
"had access to confidential information and documents from Jardin and other XPrime employees."

Frost's bio on DATAllegro's Web site makes no specific mention of his work at XPrime and says he founded DATAllegro in June 2003.

At the time of Frost's employment with XPrime, according to the complaint, Jardin had invented a new technology in distributed database architecture and filed a patent application. He was issued U.S. Patent 7,177,874 in February 2007.

The complaint said Frost filed his own patent applications in the distributed database architecture field shortly after leaving XPrime in an attempt to "convert Jardin's inventions to his own."

Jardin alleges willful infringement and is seeking unspecified damages as well as an injunction on further infringement.

Microsoft Server and Tools chief Bob Muglia announced July 24 that Microsoft was buying DATAllegro to help it compete with Oracle for enterprise data storage customers. DATAllegro's data warehousing appliances are capable of handling hundreds of terabytes.

"We've never been able to do that before," Muglia said at the time. DATAllegro will allow Microsoft to offer storage capacity "well beyond what Oracle is able to do today."

I'm seeking comment from Microsoft and DATAllegro.

I've also asked the law firm representing Jardin why he chose to file the complaint now, given that he received the patent 18 months ago.

Update, 3:15 p.m.: A representative of the firm representing Jardin offered this statement: "Because of the severity of the apparent infringement, the issue was raised as soon as possible after thoroughly investigating the matter."

Update, 3:18 p.m.: A Microsoft spokesman referred questions to DATAllegro, noting that Microsoft is not a party to the suit and has not yet completed its acquisition of the company.