Since electronic communication is no longer limited to one computer or one location, knowing how to communicate with people who use different operating systems and application software is imperative. As we communicate more over the Internet, attach files to email, and witness the exploding updates to hardware and software, understanding naming conventions is extremely important. Being able to save files that can be accessed cross-platform and with different programs is not an impossibility providing one understands a little about file formats.

The Windows environment layer sits on top of the MS-DOS operating system, masking the necessity for the 8.3 naming convention-eight letters in a filename and a three character extension the application creating the file. To determine the full 8.3 name of a file created under the Windows environment,  right click the mouse to display a dialog box which includes Properties. Explore a variety of files to determine the full file name.

The Macintosh environment, on the other hand, does not require the three-character extension because the Macintosh saves files using a dual resource fork. One fork points to the data in the file while the other fork points to the application which created the file. However, if the files are to be used cross platform, the Macintosh user must manually add the three character extension to the file name.

There are literally hundreds of three-character extensions. The website FileInfo contains a searchable database of file extensions with detailed explanations of each extension.

Some of the more popular extensions include, but are not limited to

              Productivity Software

                           .doc=Microsoft Word

                           .xls=Microsoft Excel

                           .ppt=Microsoft PowerPoint

                           .mdb=Microsoft Access

                           .cwk=AppleWorks/ClarisWorks

                           .txt=text files with no text styles such as bold, italics or graphics

                           .rtf=rich text format files with text styles such as bold, italics, but no graphics

                           .pdf=Adobe Acrobat files

                           .wks=Microsoft Works files

              Multimedia Files

                           .jpg=graphic file with JPEG compression

                           .gif=graphic file with GIF compression

                           .bmp=graphic file created with raster/bitmap/pixel graphics

                           .mov=QuickTime video, sound, or picture

                           .mid=synthesized MIDI sound file

                           .wav=sound files

                           .ra=Real Audio sound files

                           .aif=sound files

                           .avi=video files common to the Windows environment