What is an IIS application pool?

Question

What exactly is an application pool? What is its purpose?

Answer 1

Application pools allow you to isolate your applications from one another, even if they are running on the same server. This way, if there is an error in one app, it won't take down other applications.

Additionally, applications pools allow you to seperate different apps which require different levels of security.

Here's a good resource: http://www.developer.com/net/asp/article.php/2245511/IIS-and-ASPNET-The-Application-Pool.htm

Answer 2

Basically, an application pool is a way to create compartments in a web server through process boundaries, and route sets of URLs to each of these compartments. See more info here: http://technet.microsoft.com/en-us/library/cc735247(WS.10).aspx