The file system resides permanently on secondary storage, generally disks. Two characteristics make disks convenient: they can be rewritten in place and they can directly access any block of information they contain. The direct access nature of disks gives us flexibility in the implementation of files. Space must be allocated to the files so it is utilized effectively and files can be accessed quickly. Three major methods of allocating disk space are in wide use: contiguous, linked, and indexed. Engage in a detailed discussion of the advantages and disadvantages of these three methods.