to clusters in a file system. Chunk is a collection of segments. Recovery characteristics of memory (transient, zeroed, or persistent) are specified on a per-chunk basis at the time of chunk creation. Zeroed memory remains allocated upon recovery but each byte is set to zero. With transient memory, the data are no longer allocated upon recovery. Users allocate within a chunk, and do not specify a particular segment. Since segments can be arbitrarily large (within the size of the database), arbitrarily large objects can be stored contiguously. Upon allocation within a chunk, the system returns a standard DataBlitz pointer to the space, which specifies the offset within the file. The elements shown linking together segments in a chunk are themselves stored in a special chunk used for control information. Storing control information separately from the data reduces the likelihood of it being corrupted by stray application pointers... Replication In DataBlitz, data can be replicated across multiple DataBlitz instances running on machines connected by a network in a distributed environment. The primary benefits of data replication are higher availability and improved performance. For instance, if a table is stored only at a single site in a distributed setting, and if that site crashes or becomes unavailable due to a network failure, then the table would become inaccessible to other sites in the system. DataBlitz provides support for data replication at the granularity of tables. Each table can be replicated at any subset of sites in the system... References Architecture of DataBlitz The DataBlitz (Dali) Home Page Dali: Research Papers and Slides List of Linux Data Recovery software DataBlitz Main Memory DataBase System DataBlitz Storage Manager: Main-Memory Database Performance for Critical Applications Proprietary database management systems