Eng vs. Comp Sci - an engineers jealousy shines through... ;)
- Attendees
- meter@bmerhbfc
- Colin Kemp 7K76 BNR
- Author
- Colin Kemp 7K76 BNR
- Summary
For your information:
---forwarded-message---->
Nov 30 12:52:00 1995
To: Terry (T.) Lavineway (BNR) Dept C925 CAR
Jane (J.) Dowsey (BNR) Dept 7I61 SKY
Jody (J.K.) Fraser (BNR) Dept P963 CRK
Patricia (P.A.) Dy (BNR) Dept 7I61 SKY
Colin (C.W.) Kemp (BNR) Dept 7X85 SKY
Colin (C.M.) Puchala (BNR) Dept N112 SKY
Fred (F.J.) LaLonde (BNR) Dept 4Y26 SKY
Douglas (D.A.) Sander (BNR) Dept 4Y51 SKY
Cory (C.J.) Bialowas (BNR) Dept 7C13 SKY
Karen (K.) Hunt (BNR) Dept 7Y55 SKY
'[email protected]' (BNR400)
'[email protected]' (BNR400)
Vish (V.) Nandlall (BNR) Dept 7W65 CAR
From: Alan (A.B.) Williams (BNR) Dept X753 SKY
Subject: fw:H U M O U R
Laverneway, Holliday, Jane, Karen, Jimmer, Fraser, Kemp, Doogie and
Trish:
Pay VERY close attention and try to figure out the lesson to be learned!
Cory Fartypants, Fred, Colin and Vish:
You can move to the front of the classroom and choose from a variety of
ice cream treats!
I'll just sit here and write the user manual.
Head Bag
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H U M O U R
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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 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 production system. 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 omelette classes."
"The ham and cheese omelette class is worth special attention because
it must inherit characteristics from both the pork AND dairy 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. A Pentium PC with 32MB of memory, a 180MB
hard disk, and a Super 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.
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