Microsoft this week was ordered to pay a software firm $388 million in a case involving anti-piracy patents. The ruling is a reversal of an earlier summary judgment in which the software giant was found to have not infringed on a patent owned by Uniloc, a Singapore-based company. Uniloc holds a single patent, for software copy control.

Uniloc's patent dates back 15 years and describes a "method of uniquely identifying a user device, such as a PC, game console, smart phone, or cell phone, by the naturally occurring, inherent physical imperfections of that device, and then incorporating that 'physical device fingerprint' into licenses or access credentials." The company sued Microsoft in 2003, alleging that the software giant's product-activation technology in Windows XP, Office XP, and Windows Server 2003 infringed Uniloc's patent.

In August, a US District Court in Rhode Island issued a summary judgment in the case, ruling that Microsoft didn't infringe on Uniloc's patent and questioning the validity of the patent. But a jury found that Uniloc's patent was valid and ruled against Microsoft, ordering it to pay a fine of $388 million, one of the largest fines in the history of patent law disputes.

Microsoft says it will appeal the verdict. "We are very disappointed in the jury verdict," a Microsoft spokesman said. "We believe that we do not infringe, that the patent is invalid, and that this award of damages is legally and factually unsupported," he said. "We will ask the court to overturn the verdict.