XML Patent for Microsoft
The core of US Patent 7,571,169 which Microsoft was granted on August 4th refers to – "A word-processing document stored in a single XML file that may be manipulated by applications that understand XML".
A well-formed XML file must fully represent and reflect all of the formatting options supported and when saving in XML format, these formatting options must not be lost. In Microsoft's method XML files would be accompanied by a single published XSD schema file which defined the XML dialect used. Currently both OOXML and ODF are using several XML files when storing documents, compressed in a ZIP archive for easier management.
According to the patent applications, the aim of the invention is to allow any application to create, edit and view these XML documents, with the XML and XSD file together describing all the aspects of the format. In the past, critics of Microsoft's own OOXML dialect have pointed out how the definition of OOXML was too vague. This included allowing binary data into files without specifying how to deal with them. At several points in the 6,000 pages of the OOXML standard, references are made to the behaviour of certain versions of Microsoft's Word, without detailing what that behaviour is.