Which digital device creates a unique identifier for each stored file?

The file system is responsible for managing how data is stored and retrieved on a digital device. One of the key functions of a file system is the creation of unique identifiers for each stored file. These identifiers, often referred to as inodes in some file systems or file allocation tables in others, allow the system to keep track of file locations, permissions, and metadata efficiently. This unique identification enables the operating system to access and manage files effectively without confusion or duplication, ensuring that users have reliable and quick access to their data.

In contrast, while USB flash drives, data servers, and external hard drives are all storage devices, they rely on a file system to organize and manage the data they contain. They do not create unique identifiers independently of the file system; instead, they function under the constraints and structures provided by the file system in use. Thus, the correct answer reflects the essential role of the file system in generating unique identifiers necessary for accurate file management.