This is a rather generic sort of extension indicating some sort of document, usually in simple ASCII; of particular note though is the fact that both old versions of FrameMaker and MS-Word often save their native format files with this extension, and such a file may only be read with FrameMaker or FrameViewer (if a Frame document) or MS-Word (if an MS-Word document). Neither of these programs are available for all platforms, and even when they are available are usually not free. To complicate matters even further, there are several different versions of MS-Word in common use that cannot reliably read each others' files. Thus in general this format should not be viewed as portable, and chances of reading it on any particular platform are slim. Note that newer versions of FrameMaker save documents with the FM extension and Microsoft is splitting its MS-Word format into two variants that use either the DOCX or the DOCM extension. Documents saved from either FrameMaker or MS-Word that are meant for other machines should probably be saved in MIF or RTF formats (respectively) in any case.