Identifying Files

Once you have retrieved a file from its storage media you'll need to identify what kind of information you now have access to. In some cases like a phonograph record that has lost its label you may have to find an expert on the media contained on the device to identify what song you now have. However when working with files generated by computer there are several clues you can use to begin the process.

File Extension

One of the best places to start if working with a file that is still stored under its original file name is to look at the extension. For many operating systems this will be the characters at the end of the name, often separated by a period. OFFICE.DXF would be a file of with a .DXF extension which we could use to discover it is likely an AutoCad file most likely storing a drafting drawing.

Creator and Type

The Macintosh from Apple did not use file extensions, but instead used 4 character creator and type codes.

Software Utilities

There are software utilities that are able to identify file types. See file identification software.

Text Editor

Opening the file with a text editor may yield clues as to the content, even if the contents can not be interpreted by reading visually. An example would be opening .png files with a text editor; even without the file extension the second through fourth character will be "PNG".

Hex Editor

Some file types have a recognizable signature when viewed with a hexadecimal editor.