The "open" verb invokes the associated application program, which reads the file or document and presents it to the user for viewing, and possibly for editing or other action.
[3][4] The Windows shell invokes file association actions through COM, drag and drop, command line calls or through Dynamic Data Exchange.
The ability to configure advanced file association functionality, however, was removed in Windows Vista and later operating systems.
Linux-based GUIs, such as KDE and GNOME, support MIME type-based associations.
[6] The operating system uses this information to generate a list of applications which are able to open each type.
Within Finder (software) each file will be identified with a UTI and open with the default application for that type.