1. A distributed storage network comprising a plurality of interconnected computers, said computers including a plurality of host computers and at least one client computer, wherein said client computer stores client code comprising: a) storage initiation code executable to initiate storage of a data item on one or more of said plurality of host computers; b) storage condition generation code executable to generate one or more interpretable storage conditions indicating characteristics of host computers suitable for storing said data item; wherein each of said host computers stores host code including: c) host computer characteristic provision code executable to provide host characteristic data indicating one or more characteristics of said host computer; wherein at least one of said interconnected computers has: d) condition interpreter code executable to interpret said one or more interpretable storage conditions in the light of said one or more host characteristics provided by said host computer and thereby to establish whether said host computer meets said storage conditions; said host code further comprising: e) data item storage code executable to store said data item in said host computer on the execution of said condition interpreter code finding that said host computer meets said requirements.