Having come from an IT Pro/administrative focus the last few years, I was expecting that IIS 7 would be more of the same great goodness we got from IIS 6. IIS 6 was a gigantic step from IIS 5 and offered a great deal more for admins in terms of reliability, security, and performance. IIS 7 does indeed have improvements in administration, but the underlying architecture regarding working processes/application pools and http.sys doesn't change much. This design has proven itself in the field to be more than capable in the most loaded, attacked, stressed, hi-availability sites in the world.

However, if you want to modify the capabilities of IIS 6 to do things it doesn't do, that was tricky. ISAPI filters are ideally placed in the architecture for adding capabilities but are tricky to write and have limitations Also, if you want to do forms based authentication for non-asp.net applications - well, sorry, you have to write your own. All of that changes in IIS 7.

In IIS 6, the design philosophy is - start the server and enable only the features you require. Most are disabled by default but the code for those disabled features is loaded nonetheless. In IIS 7, the design philosophy is start the server and load only the features you require, the rest are NOT PRESENT. If you only want static content and a basic authentication, you list the required modules in applicaitonhost.config for those functions. You want compression? Load the module. You want to write your own authentication? Write your own - managed or native code - and load it. Goodby Isapi Filters!

This is major bigness and is only one of the many new major bignesses in IIS 7. There are big stories around  administration, integration with .net, tracing and diagnostics, WMI, and just about evey other area. Here's a pointer for admins - start now getting familiar with web.config files in asp.net. Even if you aren't deploying asp.net on IIS 5 or 6, IIS 7 will be using .config files instead of the metabase as it's configuration store. You will be able to mange it from the new Web Manager, but it's helpful to have some notion about how .config works before you get into IIS 7. In particular, for administrators, is the use of the LOCATION tag.

For developers, consider what you can do with IIS 7 by extending the capabilities of the server to interact with your application and infrastructure in ways never before possible. By creating a module and loading it as part of IIS 7 itself - you can add capabilities to the server specific to your business requirements or application.  In addition, the APIs to manage the configuration will all be fully public and part of .net. And, it’s designed with to support xcopy deployment.

More to follow

-brett