A Removable Storage system provides two classes of media pools: system and application. System media pools include free media pools, unrecognized media pools, and import media pools. Removable Storage creates one free, one unrecognized, and one import media pool for each media type in your Removable Storage system.
Also avoid snacks with a lot of salt as salt makes you thirsty. Good alternatives to trail mix are crackers, potato sticks, grapes or raisins. Plan on having something to snack on every couple of hours on a long day hike to keep your energy level up.
Backpacks are for carrying stuff that you don't need until you reach your campsite, like cooking gear and tent pegs. Backpacks are not for carrying anything you need as you're walking around, like cameras or lenses. Bag makers sell a lot of expensive packs to a lot of people new to the hobby. Don't fall into this trap.