Setting up a second monitor

Daniel Carrera daniel.carrera at
Fri Apr 21 13:40:27 UTC 2006

Karl Auer wrote:
>>You can answer all of those questions, and get a decent knowledge of how 
>>a car works, without understanding the internal combustion engine.
> Of course. But only via an ever-expanding set of rules about what to do
> and what not to do.

No, I'm thinking of things like "the radiator uses water to keep the 
engine cool so it won't melt". Here you have a relatively small bit of 
knowledge that is enough to know what the radiator does and why it's 
important, and without having to understand the Otto cycle (which has 
nothing to do with radiators anyways).

>>don't need to understand the Otto cycle to understand gears (heck, 
>>anyone who has riden a bicycle understands gears).
> No - and people who don't understand gears will happily halve the life
> of a car by revving it too low. You can add another rule, but...

So in this case, I would explain gears without explaining the Otto 
cycle. Gears are easy enough to explain ("it's just like bicycles, you 
choose the correct gear or the engine will work too hard and eventually 

>>As for metal, could you please explain to us why 
>>putting metal in the microwave is dangerous?
> Try it. Seriously. And watch carefully. With a microwave oven you don't
> want. Metal reflects microwaves (some metals absorb them).

Actually, the problem is that microwaves can induce an electric current 
through the metal. After all, electronmagnetic radiation is "just" an 
alternating magnetic field. Incidentally, this is also how antennas work 
(your favourite radio station releases electromagnetic radiation which 
induces an electric field on your antena which is tranformed into 
sound). At the intensity inside a microwave, this can cause heating and 
and in the case of pointy metals (e.g. forks) it can caus sparks.

To my knowledge, metal doesn't reflect microwaves any more than other 
common objects.

Here's an example where incomplete knowledge doesn't prevent you from 
using a microwave oven safely. Most people think that metal will reflect 
microwaves so they don't put metals in.

> No. But you need to know about them as animals, understand why they do
> some of the things they do. Telling someone "drop the line in there"
> will only work today, or in this river, or with that kind of fish. To
> get good at fishing, the person will need to learn about *fish*. How
> much depends on how good they want to get at fishing, and sure, there is
> always a point of diminishing returns.

Okay, so we agree that detailed knowledge is not necessary (and some 
times not even desirable) but partial knowledge is necessary.

>>I agree with the sentiment of the last paragraph, but I think that your 
>>examples were poor. You don't need to know the Otto cycle to maintain 
>>your car and you don't need to know what a molecular dipole is to know 
>>not to microwave your cat.
> Somewhere there is always the line below which further detail is
> pointless in a practical sense. We don't need to understand quantum
> mechanics to sit on a chair. I think most people set the line waaaay to
> high. You just set it waaaay too low :-)

Ah, you don't know where I set the line. All I've said so far is:
* Man pages are not the right place for a newbie to start.
* You don't need to understand dipoles to use microwaves.
* You don't need to understand the Otto cycle to use a car.

I never said that operating a Microwave should be reduced to 
button-pushing. I just disagreed with the statement that you need to 
understand how an internal combustion engine works (ie. Otto cycle) or 
how a microwave works (ie. dipoles).

    /\/_/   A life? Sounds great!
    \/_/    Do you know where I could download one?

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