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Local file system store

Author: Telcontar
Category: System proposals, File system
Status: Theoretical

A local file system store (LFSS) is an implementation of a file system other than the root file system that is contained within a disc image in order to permit one or more users to use a different file system than the root file system. It is effectively the same idea as mounting an ISO CD image or Apple Disk Image as a volume or folder, and like an Apple Disk Image would be fully writable. It would however not be constrained in size to a pre-set block except by quota provisions, and it would be low level enough to sit under a user account and provide their home directory, being mounted by the Session Manager as it prepares the session volume view.

Interface entry points

The principle idea of the LFSS API is to present one or more users of the system with a file system which does not naturally conform to the Virtual File System API, for example the Tagged File System, which is not hierarchical. This leads to the LFSS system having two distinct entry systems. The formal API defines how VFS sees the file system in order to support file sharing with other users and for administrators to have access to. This requires that the LFSS implementation attempt to coerce its data into the standard hierarchical folder, file, fork and metadata implementation of the VFS.

However, the implementation is also expected to provide a second API for use by the appropriate file system access UI modules so that all software will be able to present it correctly to the user.

However, software with no innate understanding of a file system outside the VFS may struggle or entirely fail to cope with the concepts involved if they cannot be correctly mapped to the VFS, so this has implications for the nature of the VFS API.