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In-Depth Information
It is a black box, something that magically does its thing. A car mechanic would
never open the boxȌit contains electronic parts that can only be serviced at the
factory. Of course, the device may have a color other than black, and it may not
even be box-shaped. But engineers use the term Ȓblack boxȓ to describe any device
whose inner workings are hidden. Note that a black box is not totally mysterious.
Its interaction with the outside world is well-defined. For example, the car
mechanic can test that the engine control module sends the right firing signals to the
spark plugs.
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Why do car manufacturers put black boxes into cars? The black box greatly
simplifies the work of the car mechanic, leading to lower repair costs. If the box
fails, it is simply replaced with a new one. Before engine control modules were
invented, gasoline flow into the engine was regulated by a mechanical device called
a carburetor, a notoriously fussy mess of springs and latches that was expensive to
adjust and repair.
Of course, for many drivers, the entire car is a Ȓblack boxȓ. Most drivers know
nothing about its internal workings and never want to open the hood in the first
place. The car has pedals, buttons, and a gas tank door. If you give it the right
inputs, it does its thing, transporting you from here to there.
And for the engine control module manufacturer, the transistors and capacitors that
go inside are black boxes, magically produced by an electronics component
manufacturer.
In technical terms, a black box provides encapsulation, the hiding of unimportant
details. Encapsulation is very important for human problem solving. A car
mechanic is more efficient when the only decision is to test the electronic control
module and to replace it when it fails, without having to think about the sensors and
transistors inside. A driver is more efficient when the only worry is putting gas in
the tank, not thinking about the motor or electronic control module inside.
However, there is another aspect to encapsulation. Somebody had to come up with
the right concept for each particular black box. Why do the car parts manufacturers
build electronic control modules and not another device? Why do the transportation
device manufacturers build cars and not personal helicopters?
