Open PART File

What are File Extensions?

File extensions are used by operating systems to specify what kind of information is stored in a file. Typically operating system user interface isolates user from file extensions by displaying icons corresponding to the file extension. But it is almost impossible to use certain features of operating system without basic knowledge about file extensions.

File extension is a short string which specifies what application should be used to view, edit or execute the file. Every operating system has an internal database which maps file extension to an application responsible for opening it. When new application is installed it supplies information about file extension mapping to that database to make sure that files created by it could be correctly mapped. It is possible that multiple applications map to the same file extension. In that case file extension database will have a default application specified to each file extension. This default application will be used to open files with this file extension unless user chooses otherwise.

Thousands of software applications exist on the market today and each of them uses one or many file extensions. That’s why number of file extensions in operating system file extension mapping database could easily be a thousand or more. Just imagine what would happen if computer would need to figure out a file type without using file extension. In that case file content had to be examined to define what application could open it. That would consume lots of computer resources with no specific benefit.

There are many other efficiencies that file extensions have. Some file extensions like BAK and TMP are used to specify that file is a backup or a temporary and could be deleted without significant consequences. Other file extensions like PART, CRDOWNLOAD or PARTIAL specify that file is currently being downloaded. ZIP, RAR, JAR, 7Z file extension let user know that data inside of file is compressed. JPG, BPM, PNG, HEIC file extensions are used by images.