Depending on how much work you want to do yourself in order
to present a proper POSIX filesystem to the client, you can
break resource managers into two types:
Device resource managers
Device resource managers create only single-file entries in the filesystem, each of which is registered with the process manager. Each name usually represents a single device. These resource managers typically rely on the resource-manager library to do most of the work in presenting a POSIX device to the user.
Filesystem resource managers
Filesystem resource managers register a mountpoint with the process manager. A mountpoint is the portion of the path that's managed by the process manager. The remaining parts of the path are managed by the filesystem resource manager.