> Firebird can run in 2 modes: as application or as service.
>
> What is the difference between these two modes and when to use it?

From Firebird's perspective, they operate exactly the same. A Firebird
engine running as an application will look no different to your
application to another Firebird engine running as a service.

An application is something you run from your user space (ie, double
clicking an icon). When Firebird is run as an application, you get an
icon in the system tray.

A service is a special type of application that does not need a user
session to be running. You can see these by running services.msc. You
can configure a lot more for each service (eg, what user account it
runs as, what action to take if the service crashes), and developers
can define their service to depend on other services.

Running as a service is far superior in a production environment. You
don't need the server to be logged in to use Firebird, and you get the
above advantages. But Windows 95, 98 and ME do not support services,
so must be run as an application.

Adam