Understanding What a Computer File Is
When you use your computer to create things, those things are stored in units of information called files. A computer file can be a document you write with your word processor. A computer file can also be a graphical image from a digital camera or an image you create with a digital paintbrush, a piece of music, a video, or just about anything. Whatever it is, the computer stores that information as a file.
The operating system manages files for you. This figure shows a variety of files displayed in the Windows Vista operating system.
Your operating system helps your programs save information from temporary storage (memory) to long-term storage (the hard drive). Further, when you need to work on the file later, you can open the file from disk; by opening the file, the operating system transfers the file's information into memory, where you can view, modify, print, or continue to work on the file.