If I create a web application and host it on a Windows Server, then as I understand it, IIS handles the initial request and routes it to the appropriate website or application. I'm under the impression that a w3wp.exe (worker process) instance is created for each application. IIS works with the worker process, which in turn works with the web application.
What happens if the application gets twenty requests per second? Will the worker process create twenty instances of the application to handle each request, or will it queue the requests passing them to a single instance of the application as and when?
I suspect it's the latter. If that is the case then am I right to think that the worker process will keep an application alive whilst it is getting requests?
I'm trying to fully understand what a web application does when it handles many con-current requests. I've tried asking this question before but struggled with the wording, so hopefully this makes sense.
EDIT: Thanks to Mason I realised that the answer was right in front of me! Web applications use DLLs, which can't run by themselves. It's the w3wp.exe (worker process) which call the DLLs to handle the requests.
The number of worker processes per web site is controlled in the application pool advanced settings (in IIS management console).
The configuration of number of concurrent requests each of the workers can handle depends on the IIS version. In IIS 7 was in the same place, for more recent versions you will have to check your machine.config (looking for maxWorkerThreads)