chap file processing and external sorting boom (armplatters read/write heads spindle (atrack (bfigure (aa typical disk drive arranged as stack of platters (bone track on disk drive platter intersector gaps bits of data sectors ( (bfigure the organization of disk platter dots indicate density of information (anominal arrangement of tracks showing decreasing data density when moving outward from the center of the disk (ba "zonedarrangement with the sector size and density periodically reset in tracks further away from the center arrangement is illustrated by figure disk drives today actually group tracks into "zonessuch that the tracks in the innermost zone adjust their data density going out to maintain the same radial data densitythen the tracks of the next zone reset the data density to make better use of their storage abilityand so on this arrangement is shown in figure in contrast to the physical layout of hard diska cd-rom consists of single spiral track bits of information along the track are equally spacedso the information density is the same at both the outer and inner portions of the track to keep