It is possible to go through this book and learn a great deal about Geronimo, its architecture, its design, and its operation without the need to try out any of the examples.
However, if you want to try out the hands-on configuration and deployment examples, you need a system with at least 1GB of RAM, 500MB or more of available storage, and a 2 GHz or faster processor (or equivalent). You will also need to have the latest version of JDK 1.4 or JDK 5 installed and running on the system before installing Geronimo.
The system you use must be networked (have a network adapter properly configured), and ideally be connected to the Internet (for downloads) at high speed.