For example, I have my school work organized in a particular folder on my C:drive. Within that folder I have more folders organized by each class. Any assignments, study notes, exams, etc, are stored in the respective folder for the specific class they relate to. This keeps everything organized and easy to access. One unique file is .rar file. It is unique due to the file extension type (.rar) and because it is not able to be read by any software, only specific (i.e. it must be converted into its original format -- mp3 for example) in order to be read.