Apollo AEGIS single level store: 96-bit identifier to uniquely get every byte in system (64-bit object id and 32-bit offset). Primary memory ends up being caches for single level store. Use shared memory for communication. FIle has to be in one place, UIDs==hostname+date/ time One machine for each object. Single directory structure for entire network. Separate using site and storage site. Whenever reads block, also checks data/time stamp. On write conflicts just reports clash. Access times with 20-30% of local access times. Problem: if change data structure definition then every program has to be changed since AEGIS is data oriented