How do you u know something like the dot matrix printer which have at tiniest 40 million strokes/wire?

How do you u know something like the dot matrix printer which have at tiniest 40 million strokes/wire?

If you want to swot about them?> http://en.wikipedia.org/wiki/dot_matrix_...
About adjectives I remember about them is they are slow as adjectives H, they make opening to much noise, etc! I DO however know one article about them! If you enjoy one, throw it in the trash!
Do you really expect how, or do you mean what do you know.
By reading.