An Alternative approach for less regular problems is to combine a view of file store and program store in the form of a persistent object store. The essential feature of a persistent store is that it contains data that is accessed like normal data but persists beyond the life of particular programs.
Persistent stores exist for sequential programs on medium-scale processors and file systems.
The challengies lie is changing scale to hundres or thousands of processors and a total of gigabytes of RAM memory, and to making effective use of a parallel distributed filesystem. A distributed object store is a powerful way to efficiently organise very large data requirements for high performance programs, across backing store and distributed and local memory. The key idea of an object store in this sense is an object-oriented data service to application programs executing on multicomputers. For a multicomputer store, the scale of the store and the need for concurrent access also lead to object-oriented databases as a significant source of ideas. The distinctive features of the project is that the objects are large in numbers and include both large and small object sizes, and that the store is realised as a distributed structure over an intimate area network of processors, with distributed local memories and a distributed file system.