Find the downloads and release notes on ibphoenix.com.

Citing the summary of the release notes:

This release contains a large number of new features, including derived tables, support for Execute Block, increased table sizes, new improved index code (the 252-byte index length limit is no longer applicable), expression indices, numerous optimiser improvements, enhanced security features, support for on-line incremental backups along with numerous other improvements and bug fixes. Please read the Release Notes for more details.

IBPhoenix publishes a series of articles called Firebird for the Database Expert about Firebird internals by Ann Harrison. Interesting reading:

1. Episode 1 - Indexes
2. Episode 2 - Page Types
3. Episode3 - On disk consistency
4. Episode 4 - OAT, OIT, & Sweep

From the introduction:

Firebird differs in significant ways from other relational database management systems. Understanding the differences will allow you to create better performing Firebird applications.

Audience: Experienced database application developers

Moving to Firebird can be disconcerting for developers who have worked with other relational database management systems. In theory, relational databases separate the logical design of an application from the physical storage of the data, allowing developers to focus on what data they want their applications to access, rather how the data should be retrieved. In practice, the mechanics of each database management system make some styles of access much faster than others. Developers learn to use methods that work with the database management systems they know.

Developers who are familiar with Oracle or Microsoft SQL Server find that Firebird indexes, concurrency model, and failure recovery behave differently from the databases they know. Understanding and working with those differences will make your move to Firebird less stressful and more successful. This paper focuses on the unusual characteristics of Firebird indexes.

I have updated the dotnetfirebird.org site backend and also cleaned up the layout a bit. These changes should allow adding new information more easily and everything should be also easier to find. Enjoy!