Cloudscape Version 10: A technical overview "The IBM® Cloudscape™ lightweight, pure Java™ technology-based embeddable architecture makes it the ideal database engine for deploying database-driven Java applications. With Cloudscape, the database engine becomes part of the application so the user never has to install or manage it. This article highlights the Cloudscape embeddable SQL database engine for Java technology, and provides you with an overview of some of the Cloudscape technical features."
I think the open-sourcing of Cloudscape (as Apache Derby) is a very significant milestone for the DBMS market. Cloudscape can be used as a program library or as a stand-alone server; it's a true DBMS, targeted at applications supporting up to 50 concurrent users and up to 20 gigabyte databases. While the most obvious synergy is for Java application development, Cloudscape also works with PHP, Perl, and Microsoft tools, so it has implications for everything from desktop database tools (today dominated by Apple Filemaker Pro and Microsoft Access) to Web/departmental database applications. It's also part of IBM's Workplace Client Technology, so in many respects Cloudscape is to IBM's architecture what SQL Server 2005 Express is to Microsoft's architecture.