Callback File System (CBFS) is a software component (library) for presenting various data as files and directories of a local virtual disk. Regardless of where the actual data are kept: in files, in database records, memory, or elsewhere - they will be treated as if they were parts of a single file system.
With Callback File System component you can create your own file system within the application you develop and expose this file system to Windows as a virtual disk or a folder of existing disk.
You don't need any kernel-mode development to implement your own file system. Use C++, C#, Visual Basic .NET, Delphi or even Java to expose any data as a file system to third-party processes.
Such approach lets you offer information stored in the database or across network, as if they were files on the local disk.