This information comes from Alex, in a ticket dealing with the Cache. Since he posted a nice long bit of information about it, I've posted it here, for anyone curious on the details of *how* it works.      What happens when the disk used for the local cache is being used? What happens when uploading?    The Upload cache and the Download cache and pinned data are seperate things and treated as such in the code Download cache is self learning, and tries to keep frequently accessed blocks of data