Explain about directory structure?
Some systems keep millions of files on terabytes of disk. To manage all these data, we require organizing them. This organization is usually divided in two parts. First, disks are dividing into one or more partitions, also called as minidisks in the IBM world or volumes in the PC and Macintosh. Partitions can be thought of as virtual disks. Partitions can also store many operating systems, allowing a system to boot and run more than one.