Questions about about how the mod works and Arma 2

[.M. 0]

I've done a little bit of reasearch myself and understand that for Day Z to work you need both Arma 2 and Operation arrowhead since Day z uses some files from Arma 2 and runs through Operation arrowhead. Not sure if that's true but it's what I found. I'm interested in getting arma 2 but i'm not completely sold on spending the extra 10 dollars for both. So here come some questions.

If I try to run day z without Arma 2 what happens?

Do I need to have both games running or does Day z go inside and get the files while you're playing through the other game?

Is Arma 2 all that different from arrow head, or is it simply a upgrade from Arma 2? In which ways?

Is it still fun just to try and survive without having to kill other humans?

Thanks for your time.

Edited January 22, 2013 by .M.

[Dancing.Russian.Man 1631]

1. The mod probably will not run if you're missing one of the two games. But you can get ARMA 2: Free (Demo of ARMA 2), and it will work, though with worse graphics.

2. Just run Operation Arrowhead. That's all you need. You can even start it through DayZ Commander (The recommended patcher for beta patches of OA as well as all the DayZ compatible maps and the mod itself.)

3. OA has things like cover/base building from what I can tell. Not sure of all the things on how it's different, but you can construct some things in OA that you can't even have in ARMA 2.

4. That is entirely up to you. I recommend watching this video entirely: