With MySQL 5.1, MySQL AB has introduced a new pluggable storage engine architecture that allows storage engines to be loaded into and unloaded from a running MySQL server.
The PrimeBase XT Storage Engine (PBXT) is a new transactional database engine for MySQL. It has been designed for modern, web-based, high concurrency environments. In May 2006, I had the opportunity to meet with Paul McCullagh, the head developer of PBXT for lunch at the Hamburg offices of Snap Innovation GmbH, the company behind PrimeBase. It was co-founded by Paul in February 1996 and is focussed on the development and sales of client/server database technology, specializing in inter- and intranet systems.
The article continues at http://dev.mysql.com/tech-resources/interviews/paul-mccullagh-pbxt.html