For storage and transmission of data, a representation different from that used forinternal processing is often necessary. In addition to the actual data representing points inan image or characters being displayed, the system must store and pass along informationthat describes or interprets themeaning of the data. Such information is known as metadata.In some cases, the description is simple: to read a pure text file may require only a singlepiece of information that indicates the number of characters in the text ormarks the end ofthe text. A graphic image or sound requires a much more detailed description of the data.To reproduce the image, a system must know the type of graphical image, the number ofcolors represented by each data point, themethod used to represent each color, the numberof horizontal and vertical data points, the order in which data points are stored, the relativescaling of each axis, the location of the image on the screen, and much more. For a sound, the