RioFS is a userspace filesystem for Amazon S3 buckets that runs on Linux and Mac OS X. It supports versioned and non-versioned buckets in all AWS regions. RioFS is intended as a storage backend for legacy daemons that cannot talk natively to S3. It handles buckets with many thousands of keys and highly concurrent access gracefully.
RecDB is a recommendation engine built entirely inside PostgreSQL 9.2. It allows application developers to build recommendation applications using a wide variety of built-in recommendation algorithms such as user-user collaborative filtering, item-item collaborative filtering, and singular value decomposition. Applications powered by RecDB can produce online and flexible personalized recommendations to end-users. It is easily used and configured and allows novice developers to define a variety of recommenders that fits their application's needs in few lines of SQL. It can seamlessly integrate recommendation functionality with traditional database operations.
InfiniSQL is a distributed in-memory NewSQL relational database management system (RDBMS). It excels at performing complex transactions which involve records on multiple server nodes. It is engineered around the actor model of concurrent programming, which enables unique scalability capabilities.