Architecture of IIS

Windows is the OS that divides into 2 modes

1. kernel mode: it is fastest and provides the direct access to hardware and Kernel mode has full access to every resource

things running in kernel mode are bypassing most operations as the operating system runs in this mode

Ex: device drivers

a badly written device drivers can crash the entire operating system and it causes the blue screen issue

2. User mode: where the actual s/w executes and uses the actual memory and has restricted access to resources.

it is the most protected area. if anything happened in this mode then OS will interpret and correct it but in kernel mode it is not possible

IIS is the tool which performs the operation in kernel mode and user mode:

IIS have the http listener running in kernel mode and it is listening all the requests coming from Web

IIS have the multiple websites and http listener listens the web requests and dispatches the request to the user mode process called worker process

these worker processes are seen in task manager and these took the requests and send according to the request type: if it is asp.net request then it executes the asp.net script

in addition to dispatching the request to the worker process, it will check the any requests coming from web is not having the requested pages in the server

then it discards the requests immediately.

if the worker process processing the request is of type badly written code one, then that worker process is killed and it will not affect the other worker process

Windows kill that worker process and claim the memory

IIS is having modular architecture:

Going to site in IIS gives the site information in the form of modules Like Asp.net, IIS, Management

For this IIS, you need least windows 2008 and With IIS 7.0, you will get the IIS 6.0 also

Previous of versions of IIS is using the command line for managing the IIS

IIS 7.5 uses the windows PowerShell and MS used VB script form previous versions and they deprecated and now they migrated to PowerShell scripts

Regards,

Chaitanya