Wow! thanks, your post has helped me understand all this so much!
I have one other quick question however.
if I do a var1 DS 4, how do I go about assigning values to those four bytes? could you possibly provide me with an example of how to assing values to those bytes, how to read them, modify them and save them to the same location? I think I understand how they mostly work, but an example would be most appreciated.

Thanks again!
Phil