Difference Between Computer Science and Engineering
     Once upon a time, in a kingdom not far from here, a king summoned two 
     of his advisors for a test. He showed them both a shiny metal box 
     with two slots in the top, a control knob, and a lever. "What do you 
     think this is?"
     One advisor, an engineer, answered first. "It is a toaster," he said. 
     The king asked, "How would you design an embedded computer for it?" 
     The engineer replied, "Using a four-bit micro controller, I would 
     write a simple program that reads the darkness knob and quantizes 
     its position to one of 16 shades of darkness, from snow white to 
     coal black. The program would use that darkness level as the index 
     to a 16-element table of initial timer values. Then it would turn on 
     the heating elements and start the timer with the initial value 
     selected from the table. At the end of the time delay, it would turn
     off the heat and pop up the toast. Come back next week, and I'll show 
     you a working prototype."
     The second advisor, a computer scientist, immediately recognized the 
     danger of such short-sighted thinking. He said, "Toasters don't just 
     turn bread into toast, they are also used to warm frozen waffles. 
     What you see before you is really a breakfast food cooker. As the 
     subjects of your kingdom become more sophisticated, they will demand 
     more capabilities. They will need a breakfast food cooker that can 
     also cook sausage, fry bacon, and make scrambled eggs. A toaster 
     that only makes toast will soon be obsolete. If we don't look to the
     future, we will have to completely redesign the toaster in just a few 
     "With this in mind, we can formulate a more intelligent solution to 
     the problem. First, create a class of breakfast foods. Specialize 
     this class into subclasses: grains, pork, and poultry. The 
     specialization process should be repeated with grains divided into 
     toast, muffins, pancakes, and waffles; pork divided into sausage, 
     links, and bacon; and poultry divided into scrambled eggs, 
     hard-boiled eggs, poached eggs, fried eggs, and various omelet 
     "The ham and cheese omelet class is worth special attention because 
     it must inherit characteristics from the pork, dairy, and poultry 
     classes. Thus, we see that the problem cannot be properly solved 
     without multiple inheritance. At run time, the program must create 
     the proper object and send a message to the object that says, 'Cook 
     yourself.' The semantics of this message depend, of course, on the 
     kind of object, so they have a different meaning to a piece of toast 
     than to scrambled eggs."
     "Reviewing the process so far, we see that the analysis phase has 
     revealed that the primary requirement is to cook any kind of 
     breakfast food. In the design phase, we have discovered some derived 
     requirements. Specifically, we need an object-oriented language with 
     multiple inheritance. Of course, users don't want the eggs to get 
     cold while the bacon is frying, so concurrent processing is 
     required, too."
     "We must not forget the user interface. The lever that lowers the 
     food lacks versatility, and the darkness knob is confusing. Users 
     won't buy the product unless it has a user-friendly, graphical 
     interface. When the breakfast cooker is plugged in, users should see 
     a cowboy boot on the screen. Users click on it, and the message 
     'Booting UNIX v. 8.3' appears on the screen. (UNIX 8.3 should be out 
     by the time the product gets to the market.) Users can pull down a 
     menu and click on the foods they want to cook."
     "Having made the wise decision of specifying the software first in 
     the design phase, all that remains is to pick an adequate hardware 
     platform for the implementation phase. An Intel 80386 with 8MB of 
     memory, a 30MB hard disk, and a VGA monitor should be sufficient. If 
     you select a multitasking, object oriented language that supports 
     multiple inheritance and has a built-in GUI, writing the program 
     will be a snap. (Imagine the difficulty we would have had if we had 
     foolishly allowed a hardware-first design strategy to lock us into a 
     four-bit micro controller!)."
     The king wisely had the computer scientist beheaded, and they all 
     lived happily ever after.
     #-- Author Unknown.