TechArchive

This article was originally written in the period 1995-2000

Folk have said “Sometimes Griff, your column sounds like you’re ranting!”. Ah well, in for a penny, in for a Euro. Here’s this month’s warm-up rant.
DYJHIW (Don’t you just hate it when) you go to a show like Manufacturing Week, trog round all day and collect a load of business cards from companies because you know they’ll be of use one day in the future, but right now you’re not too bothered about collecting a carrier bag full of brochures (as your arms are long enough already). You get them home, and find that most of them say nothing about what the company does.
What use is that? If I find your business card in the bottom of a drawer and all it has is your name, you’ll never hear from me again. Crazy.
OK, on to the main feature rant. Thanks to my ex-landlord Tony Colliver for emailing me this fine story. 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?” he said.
One advisor, who was an engineer, answered first. “It is a toaster,” he said. The king asked: “How would you design an embedded computer for it?” (Like they do Ed). 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 programmer, immediately recognised 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…” (Here the king lost track of the conversation for about 15 minutes) “…As you can see”, continued the programmer, “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 the message `Booting Unix v8.3′ appear on the screen. Unix 8.3 should be out by the time the product gets to 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 microcontroller!”
The king wisely had the computer programmer beheaded, and they all lived happily ever after. I guess that speaks for itself.