Disk storage refers to a broad range of devices in which information is placed on disks in digital form (more specifically, as bits that consist of the binary digits "1" and "0"). For many computer systems, especially for smaller computers such as personal computers (PCs), disk storage is the only method for retaining information (or data) after the computer is shut down. There are three types of disk storage technology in common use today: magnetic disks, optical disks, and magneto-optical disks. Although the three types of disks utilize differing technologies to store information, they all share some fundamental attributes. First, each type of disk must be within an appropriate disk drive before information can be read from, or written to, the disk (in this context, "reading" means to retrieve information and "writing" means to store information). Some disk drives are designed to house disks permanently (i.e., the...