Directories or folders The files on your computer contain information used by the computer and can be data, source code, a binary executable program, music or images. Each file is associated with a file name which generally consists of a base name followed by a dot and then a file extension. The following are examples of file names that you might be familiar with: HistoryReport.doc radioactive_ImageDragons.mp3 passport_picture.jpg The base file name should be a label that allows the user to recognize the content. Extensions indicate the type of file that is in the file. Below are listed several file extensions you are most likely familiar with.