The VFS serves as an abstraction layer that gives applications access to different types of file systems and local and network storage devices. For that reason, a VFS may also be known as a virtual file system switch. It also manages the data storage and retrieval between the operating system and the storage sub-system. The VFS maintains a cache of directory lookups to enable easy location of frequently accessed directories.
Sun Microsystems introduced one of the first VFSes on Unix-like systems. The VMware Virtual Machine File System (VMFS), NTFS, Linux's Global File System (GFS) and the Oracle Clustered File System (OCFS) are all examples of virtual file systems.
See also: file virtualization