PerDiS: Persistent Distributed Store

Hmm, PerDiS is another tasty free software treat.

PerDiS is a middleware that insulates applications from operating system dependencies, from the network, and from file systems. Interfacing to PerDiS is easy and natural: an application using only needs to allocate its data in (the PerDiS-managed) memory. Since the major PerDiS abstraction is just memory, sharing some object is just a matter of setting a pointer to it.

An existing, centralized, single-user application can be ported in a matter of hours in many cases. Through PerDiS, its data automatically becomes persistent and shared over the network. PerDiS insulates applications from one another by using transactions, so the application writer does not need to worry about concurrent updates. Caching and replication techniques ensure that data is accessed efficiently and rapidly. Automatic persistence and garbage collection take away many of the headaches of sharing. Each set of objects is protected from unwanted access or tampering by distributed access control and encryption. PerDiS makes it possible to share data securely within a Virtual Entreprise, a temporary grouping of different businesses.

The PerDiS memory manager automatically takes care of distribution, storage, and deallocation. Data created or updated by one process is automatically made available to other processes (provided the user provides correct credentials). PerDiS implements persistence by reachability, meaning that any shared datum is automatically backed up on disk, while non-shared data is detected and deleted by our novel distributed garbage collection technology.