Patent Ruling Against Microsoft Hinges on Meaning of Custom XML

Analysis: A federal judge has ruled against Microsoft in a patent violation lawsuit brought by a company called i4i involving the use of XML in Microsoft Word, but the ruling contains some interesting language that raises many questions. Jeff Cogswell takes a close look at the ruling and what it might mean.

A Federal judge in Texas handed down a ruling Aug. 11 barring Microsoft from continuing to sell and support its Microsoft Word software on the grounds that it violates a patent owned by a company called i4i. But the ruling has some odd things in it that have already caused a good bit of debate on blog and news sites. Here's one part of the ruling:

"Microsoft Corporation is hereby permanently enjoined from ... selling, offering to sell ... any Infringing and Future Word Products that have the capability of opening a .XML, .DOCX, or .DOCM file ("an XML file") containing custom XML."

The odd wording here is "custom XML," which appears several times in the ruling. Based on the comments in response to eWEEK's articles on the ruling, as well as comments I've seen elsewhere, a great deal of people think the problem was that Microsoft uses XML as its format. But that isn't the case. The ruling focuses on the use of custom XML. The ruling is not about the fact that Word uses XML. If it did, there would be a worldwide disaster, considering how prevalent XML is.

But what exactly is custom XML? To start with, let's look at the claims of the patent itself and try to make a connection. The patent, which was written back in 1994, covers a new way of providing formatting in a word processing program. To understand the claims of the patent, it's important to note the distinction between what the inventors call content and what are called metacodes (which are ultimately formatting codes).