In this exercise you will create a data flow diagram. You may use paper and pencil or optionally use a diagramming tool like Microsoft Visio. As you complete this exercise, consider these questions:

What processing is done? When? How? Where? By whom or what?

What data is needed? By whom or what? for what? When?

There's this man who sleeps most of the year and only gets up at Christmas. He's got this band of fairies and elves that do things for him. The elves take care of the mail that he gets all through the year, and the fairies deal with his stock, presents which are made to order by dwarves.

Throughout the year this man (Santa) gets letters from boys and girls asking for presents. When an elf gets a letter from a boy or girl who has been good, they send the letter to the dwarves, who make the requested present. (Letters from boys and girls who have been bad, get sent back to the senders, with a 'do better' message.)

The dwarves send the newly-made presents to the fairies who pack them, taking care to put them in the right sacks so that on Christmas Eve, Santa can deliver them without a hitch.

Draw a Data Flow Diagram for the system described.