The Berkeley Database Package (DB) is a programmatic toolkit to
provide database support for applications, including client/server
applications. It includes B+tree, Extended Linear Hashing and
fixed/variable-length record access methods, transactions, locking,
logging, shared memory caching and database recovery. The source
code is freely available, and may be freely redistributed.

For further information, see:

	http://www.sleepycat.com/db