There is no option to use fb embedded, it would be good to have that option for many reasons.
Ideally, you would be able to switch at runtime, but making that happen would be non-trivial since the way Ruby native extensions work the shared library is selected at compile time.
It may be possible to build two separate gems by replacing "fbclient" with "fbembed" in extconf.rb, but I haven't tried this.
That would be great, specially since hosting solution often doesn't offer Firebird installed.
One would have to limit a hosted application to a single instance with embedded Firebird, since the process takes exclusive control of the database.
I'm aware of that, but is the only option I hace due to the poor Firebird support from the hosting options, this is something I've done with ASP.net, now, I think the multi-instace access is contemplated for the next Fb release.
Other usage is to have a local database in your application as cache, since firebird allow to easily change from a server database to an embedded one I often use an ambedded fb for local caches in my applications, the application still connects to the server database, but also has a local cache in the client to work disconnected.
This would make a great sqlite alternative
It might be possible to do late binding like we do in ibpp
In the followng thread "libfbembed and Debian/Ubuntu Builds" there is a patch for inspiration
and the disscussion on ibpp list