Directory Structures:
A directory or storage device can be used in its entirety for a file system. It can also be subdivided. For example, a disk can be partitioned into quarters, and each quarter can hold a file system.
Storage devices can also be collected together into RAID sets that provide protection from the failure of a single disk.
Partitions: Partitions are also known as slices or mini-disks.
Volume: Any entity containing a file system is generally known as a volume. The volume may be a subset of a device, a whole device, or multiple devices linked together into a RAID set. Each volume can be thought of as a virtual disk. Volumes can also store multiple operating systems, allowing a system to boot and run more than one operating system.
