Open Office XML Format

Open Office XML Format

This format is often referred to as OOXML, OpenXML or Open XML. It was introduced by Microsoft in 2006 and was developed as a successor to Microsoft binary document storage format.

The problem with previous format is that no other software development company was able to use it effectively besides Microsoft. Data was stored in binary format and protected by a significant set of patents making usage of this format risky and complicated.

In September 2006 Microsoft published Microsoft Open Specification Promise (OSP) which is irrevocable promise by Microsoft to not assert legal rights over certain Microsoft patents or implementations. Technically it gives rights to 3rd party software developers to create applications which can read, modify and create Microsoft Office compatible files without violating any patents.

File in OOXML format consists of several XML files compressed using ZIP algorithm. Thus if you want to view what's inside DOCX, PPSX, XLSX file you can just rename it to ZIP and open it as usual ZIP archive. Note that content of it is quite complex and only professional software developers can read it.

Office MathML (OMML)

Office Math Markup Language is a new format introduced in Office 2007 to represent complex markup like footnotes, comments, images and formulas.

DrawingML

DrawingML is an XML based language for vector graphics. It is used to draw shape elements, graphical tables and charts.