Extensible file system

A computing device comprising a file system and a computer readable storage medium that stores information within a volume on the computer readable storage medium, the volume comprising:

• a boot parameters component that specifies boot parameters for use by the file system;
• a file allocation table component containing a file allocation table for use by the file system;
• and
• a plurality of directory entries according to a directory structure, each of the plurality of directory entries are either a primary directory entry or a secondary directory entry, each of the plurality of directory entries is typed, wherein primary directory entries define potentially different formats,
• each secondary directory entry being associated with a primary directory entry and defining metadata extending the metadata of the associated primary directory entry, each primary directory entry being classified as either a critical primary directory entry or a benign primary directory entry, and each secondary directory entry being classified as either a critical secondary directory entry or a benign secondary directory entry, said secondary directory entries follow a primary directory entry;
• the file system ignores a benign primary directory entry, if it is not understood, and, when enumerating directory entries during a process of mounting the volume:
• prevents the volume from being mounted if the file system does not recognize the type of a critical primary directory entry;
• and
• thereafter, when performing user-initiated processes, enumerating the secondary directory entries, wherein
• the file system ignores a critical secondary directory entry and the primary directory entry with which it is associated if the file system does not recognize the type of said critical secondary directory entry, and
• the file system ignores a benign secondary directory entry if the file system does not recognize the type of said benign secondary directory entry.