Multisite CI installations - HOW TO

[eluser]developer10[/eluser]
[quote author="Zeeshan Rasool" date="1272283408"]You can handle these applications with single CI installation but on same server. Yuo can either keep CI installation separate or keep application folders inside CI installation. This makes it independent and you can set any application as default in index.php[/quote]

i wonder if i would be able to have all the application "default" at the same time. what does this mean?
Any app at any given time should be accessible for a visitor - without that i really dont see the point of
having multisite CI installation on a live server.

Of course, i'm already using multisite installation on my localhost, and am just switching between apps
when developing.

I wonder if a codebase could be kept in a site's root, and application folders be kept in a subdomain's
folders (which path is "rootfolder/subdomain") and have no actual default app - any of them should work
when accessed.

Is this possible?