I

File Types

I.1 File Types

Most operating systems distinguish between one file type and another by using a three-or four-letter file extension. Mac OS Classic used a four-letter code for type and creator properties, which were stored in the file metadata information. Both mechanisms are supported in Mac OS X. Windows uses file extensions to associate the file with an application, while Linux- and UNIX-based systems delegate the file-type recognition to the application-level software.

These file-mapping mechanisms are used by the operating system to run the appropriate application when the file is opened, although it is the shell or finder/explorer application that arbitrates this.

Table I-1 summarizes file extensions and the owner, codec, or ...

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