Files, File Types, File Extensions, and Folders

File – A computer file is a way to store information on a computer so it can be used later, and perhaps exchanged with other people. Depending on what you are doing, you might have different types of files. For example if you write an essay for a class, then you would save it in a file. If you take a picture, that is a file.

File Types and File Extensions – Different programs save their files in different formats. This is so the program won’t get confused and try to use an music file in a photo editing or word processing program. File extensions are the three (or more) characters at the end of a filename, which follow a dot, e.g. essay1.doc, familyphoto.jpg, budget.xls. Here are some examples of different kinds of extensions:

  • Microsoft Word create files with extensions like .doc or .docx.
  • Photo editing programs create files with extensions like .jpg, .gif, or .png
  • Music programs create files with extensions like .mp3 or .wav.
  • Microsoft Excel creates spreadsheet files with extensions like .xls or .xlsx.

Directories or Folders – are used to store groups of files. For example, say you have a couple hundred photos from your last camping trip, and you download them to your laptop to sort and select the best ones. You don’t want them to get mixed in with all the other photos you’ve taken over the years, along with all the other files on your computer, so you create a separate folder to hold them. In this case, you could call it something like CampingTripPhotos.

Subdirectories or Subfolders – While folders are useful for separating files into different groups, having only one set level of folders could get confusing too. So, you just create a new folder inside another one, to create a subfolder. For example, your CampingTripPhotos could go inside a larger folder called Photos. Generally, this kind of arrangement is up to you, but it’s better to organize your files in advance, instead of waiting till you have thousands of files in one folder.

Quick visual overview of files, folders, and directories from Lynda.com (under five minutes) -

Back to top