∗ Please see www.nestproject.com for more information. Current storage appliances have been traditionally designed to meet either the storage demands of a local or a wide area network. The grid is unique in that it escapes this limitation and allows users to share resources both within and between local area networks. However, this freedom creates many new challenges to storage appliances that would be used on the grid. NeST is a user-level software-only storage appliance that is being specifically designed to meet the unique storage needs of grid computation. A virtual protocol layer allows arbitrary data transfer and authentication protocols to be used. An abstract storage interface allows a wide range of physical storage devices to be optimally utilized. Multiple concurrency architectures provide the flex needed to achieve high levels of throughput across multiple host platforms. Flexible mechanisms allow storage within NeST to be reserved and there is support for differentiated levels of service as well. Finally, a policy language such as Condor ClassAds can be used to advertise the NeST and allow discovery of both the physical storage and of the data contained thereon.