Peter Reinhart's sourdough and barm questions

Hi, I have just ventured into my first sourdough starter from the Bread Baker's Apprentice and I have a few questions.  I have made the seed culture and the barm and am now beginning the process of actually making the bread.  First of all what exactly is the barm, and can I keep it in my fridge for years, like a sourdough, as long as I refresh it?  Can I use it as sourdough starter for other recipes?  Also when do you refresh the barm and how exactly, I don't understand how much I am suppose to feed it.  I know he explains refreshing, but I'm still a little lost.  Any tips or ideas would be greatly appreciated!  Thanks so much!