Gluster users - Jun 2011 - Difference type of volume in GlusterFS

Hi, I have read the documentation on www.gluster.com but I don't
understand the difference from some volume type.

I know that Replicated is similar to a RAID1 on 2 server, but I don't
understand how work Distributed and Striped volume.

Someone can help me to understand ?
thank you very much.