The differences between 'when' and 'while'?

[Genzo]

As my title, could anyone tell me the differences between 'when' and 'while'? Thank you.

[Inga]

We usually use while to say that two longer actions or situations go/went of at the same time: While you were reading the paper, I was working.
We prefer when to refer to ages and periods of life: When I was a child we lived in London.
You can add as to this list of words. As is used to talk about two situations which develop or change together: As I get older I get more optimistic.
We can use all three words to introduce a longer 'background' action or situation, which is/was going on when something else happens/happened:
As I was walking down the street I saw Joe driving a Porsche.
The telephone always rings when you are having a bath.
While they were playing cards, somebody broke into the house.
_________________
I am an incurable optimist.

[Edison_Chen_e_c]

From 'Practical English Usage' by Michael Swan: When/While/As
(Sorry, but I don't have the book now, if there's something wrong please help correct it, thanks very much.)

1.background situation
When/While/As I was walking down the street, I saw Peter drive a Volvo passing by.

2.a period time (usually progressive form)using while/when
While/When I was playing cards, Davied came in.

3.two acting, two continual one (two progressive forms)
While I was having dinner, Mom was watching TV.

4.two simple tense while/when either can be used, yet if what we talk about is about the age or kinda life step, usually using 'when'
I had lunch in the restaurant while/when she studied in the library.
Mary's mother died when she was 12. (speaking of the age)
Mary married a cute guy when she was in London. (speaking of a kind of life step)