All applications save data into binary files in predefined way and order and those predefined ordered files, because of that, have characteristic file format. In purpose of easier identification, ever since DOS days, name of the file has additional three characters called file extension. In the beginning, text files were mostly saved in pure text format with DOC extension, which represented first three characters of the word document.

As documents were, more and more often, made as combination of text, graphics and other different objects, DOC format became proprietary binary format. In 1980 WordPerfect chose this extension for its word processor, and in 1990 Microsoft did the same thing with their text processor Word, which is nowadays indissolubly connected to DOC extension.

Different versions of Microsoft Office had different algorithms for writing data into files, but they all kept the same file extension. The fact that all DOC format documents are not coded the same way, made sharing of those documents with users that had older versions, pretty complicated. Microsoft Office suites are compatible with older file formats, and they can write and read them without any problem. Users of older version very often resolved this problem with plug-ins that converted new version into format that their version can read.

Additionally, things got more complicated when new players appeared, like Open Office or Google Docs. Lately, WordPerfect lost its popularity under pressure of freeware Office suites. Considering the fact that Microsoft is still dominant in Office software section, it is clear that MS DOC file format is logical solution for universal Office file format. Each new Office suite, that wishes to become users’ choice, has to offer compatibility with Microsoft Office formats like DOC and XLS.  Microsoft Word DOC format is Microsoft’s private property, and it is not open source, which makes its coding and decoding really hard for programmers. Finally, in February 2008, Microsoft offered DOC and XLS formats under Microsoft Open Specification Promise license, which should allow better support of these formats on non-Microsoft applications. Introducing its new version of Office suite, Microsoft established new generation format as well, but this time with new extension DOCX (Office Open XML) and XMLX. These formats are open source, and they are based on XML and ZIP technologies, which enable simple access to file structure. However, advanced options of new MS suite are still not supported by concurrent products, so after a couple of tests we concluded that there is no purpose of any further testing DOCX format compatibility.


DOC format test

In order to grade compatibility, we made original Word document using MS Office 2007, saved it in DOC 97-2003 and DOCX formats, and then opened those files in OpenOffice 2.4 and Google Docs suites. Results were interesting. OpenOffice handles DOC 97-2003 text documents pretty good, whereby almost every text element was displayed correctly. We weren’t able to reproduce DOCX format so no further tests will be done for DOCX format. We bumped into some problems with couple of DOC format options that are not used so often. For instance, colored document background is not stretched across the whole page, but only inside the margins, which can even be logical solution if document is printed, but then again not absolutely identical to original. OpenOffice partially gets along with advanced elements, like Textbox and WordArt. Textbox kept its form, but text within lost its margins. 3D version of WordArt objects that we tested was drawn correctly, with slightly changed quality and position. Graphic objects often experience color changes. Generally, document looks like the original, but many corrections are needed if we want to keep its original form.