The Ceph architecture can be pretty neatly broken into two key layers. The first is RADOS, a reliable autonomic distributed object store, which provides an extremely scalable storage service for variably sized objects. The Ceph file system is built on top of that underlying abstraction: file data is striped over objects, and the MDS (metadata server) cluster provides distributed access to a POSIX file system namespace (directory hierarchy) that’s ultimately backed by more objects.

Flare is distributed, and persistent key-value storage compatible w/ memcached

An embedded Java database (think Sqlite). Formerly IBM CloudScape (?)

Disk usage utility for Unix, with an interesting visualization system.

"Tahoe": a secure, decentralized, fault-tolerant filesystem.

Applications that process large volumes of data (such as, search engines, grid computing applications, data mining applications, etc.) require a backend infrastructure for storing data.

memcached is a high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.

It typically takes at least a generation before the social impact of a ubiquitous new technology becomes obvious.

Lamport's Paxos

Paranoid privacy-freak offsite storage, and cheap.