Open DAT File

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What is File Extension?

File extensions are used by the operating system to distinguish files based on what is stored inside. File extension specifies what information is stored inside the file and which application could be used to open it. For example, JPG file extension means that image is stored inside the file, while a file with MP4 extension will have a video clip inside.

To quickly find out an application which can be used to open the file operating system has a database of associations between file types and applications which can open them. When a new application is installed it sends information to the operating system about file extension which it can open, and file extension associations database is updated. Correspondingly when application is uninstalled file extension associations are removed. If there are multiple applications registered which can open one file extension, then a list of applications which can open specific file extension is formed.

When a user double clicks on a specific file operating system looks through the file extensions associations database for applications which can open that file. If application is found, then operating system will request it to open the file. If there are multiple applications that can open the file, then the default one will be chosen. If there are no applications in the database which can open the file, then the operating system will ask user to select an application manually from a list of all applications available in the file extension associations database.

File extensions significantly simplify many tasks which could be performed by the operating system. For example, when user needs to find a text inside a file, operating system can go through all files with textual file extensions and scan them for a queried string. Without file extensions it would be impossible to distinguish between text, image and movie files. Or if user needs to find all image files on the computer there is no need for the operating system to even look inside the file. All it needs to do is to look through file extensions and only show files with file extensions used to store images (like JPG, JPEG, PNG, BMP, etc.).