Drupal Small Guide & Arquitecture

While looking for some specific Drupal architecture information, I came across this small, focused tutorial.
I recommend it for beginners: Tutorial Drupal.

I also find what I was looking for:

• An Introduction to Drupal Architecture
• Varnish HTTP Accelerator Integration
• Pressflow
• Drupal API, obviosuly

Specially using Oracle database as the data repository for Drupal:

• Oracle integration
• Oracle driver

./M6