How exchange technically done with wallet daemon?

So with exchange's web server, in that same server, all coin's daemon should be running with full blockchain's data in same server?
It should be ubuntu? or window server possible?

Then give specific coin's address to each specific user, and how to check realtime that if that user send bitcoin to his specific address? so that apply to his exchange's bitcoin balance increasing automatically.

How exchange implement its server hardware structure?

And how implement deal on exchange between users? If some user buy some altcoin by his btc, it finishes instantly, so this means, his btc coin actually does not transfer to seller's btc address because if really putting on bitcoin network, it will take more than 10~30 minutes.
Is this right?

And how implement so called [Hot wallet] and [Cold wallet] of exchange?