It is common to have all the files organized in a single structure of directories, called as a file system tree in a UNIX environment. The directory structure starts with a root directory (/).
Files can be stored on different types of media or networks. The UNIX system enables you to attach and detach files stored on a given media. The process of attaching and detaching files from the directory is called mounting and unmounting of files. The directory, where a subtree or a file from one media is attached to the complete directory structure, is called a mount point.
A file system is a structure of directories that is used to organize and store files. Any of the items from the following list can be termed as a file system:
Particular type of file system: disk-based, network-based, or virtual
Entire file system tree, beginning with the root (/) directory
Data structure of a disk slice or other media storage device
Portion of a file tree structure that is attached to a mount point on the main file tree so that the files are accessible
The Oracle Solaris operating system (OS) uses the virtual file system (VFS) architecture, which provides a common interface for various file system types. The VFS architecture enables the kernel to provide a common interface for usual operations such as reading, writing, and listing files. The execution of these operations are managed by kernel modules for a specific file system. The VFS architecture also makes it easier to add new file systems.