According to one embodiment, a method includes presenting a medium to more than one user as being exclusively occupied by whichever user attempts to access at least one file from the medium, writing a first file managed by a first user to a data partition of the medium, and storing a first user identifier (ID) that identifies the first user as metadata to an index partition of the medium in response to writing the first file managed by the first user. In another embodiment, a method includes reading metadata from an index partition of a medium from a first user of a plurality of users, extracting first file attribute information associated with a first user ID that indicates a first user from the metadata, and reading a first file based on the first file attribute information associated with the first user ID from a data partition of the medium.