Scales questions!

1. What exactly are scales, and where can i find most of them with modes?
2. Are scales made to be downstroked only or up and down stroked?
3. Do guys like steve vai, john petrucci, and malmsteen use scales in there sick licks?

Could someone pls point me in the right direction, I only know 1 scale and thats the major penatonic, im want to learn to play them super fast and know most of the scales, like dorian and iorian....

1. Sclaes are a sequence of notes. (ill leave the tehcnical explaining to someone else)

2. Pick them which ever way you want, it all depends on the music style. Heavy metla is mainly downpicked for that heavier, harder attack. but guys like vai and stuff always up and down pick becuase its faster and smoother.

3. Almost every lick you hear form anyone will be derived from a scale whether intentionally or not.