ROM Hack DS Game Saves

[Cuber456]

Hoping someone can point me in the right direction. I'm trying to reverse engineer DS save files.

First things first, I'm wondering how saves are read from carts. For example, is save data loaded directly and *as needed* from the cart? Or perhaps all save data loaded into memory, utilized for whatever purpose and then thrown away?

Using no$gba, I think this knowledge will help me in locating the save data as it is actively being used so that I can study the save format.

I know there is also the tech aspects of it as well:

http://problemkaputt.de/gbatek.htm

I just don't know what to be specifically looking for.

Thanks!