Is your feature request related to a problem? Please describe.
The existing OS_FILESYS_TYPE_DEFAULT type is used to cover basically any filesystem mapping that doesn't directly fall into the other categories (e.g. NORMAL_DISK, VOLATILE_DISK, etc). This includes the traditional FS_BASED types, which just map to another existing place in the filesystem.

Describe the solution you'd like
The code should provide a unique value for FS_BASED maps, which is a valid mapping type, as opposed to not knowing what mapping is being used.

Additional context
Distinction between known FS types and unknown types is required for running without Volume Table in BSP.

Requester Info
Joseph Hickey, Vantage Systems, Inc.