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Comic Relief

Mail*Link(r) SMTP               Comic Relief

Here is a message I received via email from one of my nieces. ------

"Let them eat Toast!"

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 
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 microcontroller, 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 years."
"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 classes."
"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 
"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 Pentium with 16MB of memory, a 160MB 
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 microcontroller!)."
The king wisely had the computer scientist beheaded, and they all lived 
happily ever after.