Confusing Text #1

This is the first of (most probably) many posts to come that describe confusing text I come across while reading (mostly from books).
Book: Microsoft Office Sharepoint Server 2007 The Complete Reference (McGraw Hill)
Page: 14
Focus of text: Describing Sharepoint architecture and how it compares/relates to IIS, even giving an analogy to IIS.
Quote:
"IIS SharePoint has a built-in interface that leverages Internet Information Services
(IIS) not as an ISAPI filter (something that simply captures requests), but as a coprocess
that provides SharePoint with application and site self-provisioning features,
as the interface to the web presentation engine used to render web pages. This
interface enables SharePoint to manage its own infrastructure from a web application
point of view, handling the creating of virtual directories and web sites within IIS.
Conceptually, the core of SharePoint looks something like this:

As you can see, there’s not much to it at the high level, because the real guts of the
application reside within SharePoint itself, in the way it manages applications and sites
starting with the Central Administration Site. The Central Administration site is created
when SharePoint is first installed and provides the administrative interface needed to
enable services, create applications, sites, and so on. It is here that you can see the oneto-
one relationship between SharePoint and IIS:

With the SharePoint interface to IIS, it is from this Central Administration site and not
IIS where additional applications and sites are created. In fact all settings, including such
basics as time zone and application pool accounts are set in Central Administration."


The HUH!?
Check this: "not as an ISAPI filter" ... "but as a co-process that provides Sharepoint with application and site self-provisioning features, ...". I agree that it is not an ISAPI filter but why mention that it is a co-process? Am I missing something? Doesn't SharePoint run over ASP.NET (which communicates with IIS using an ISAPI extention, yes I know that's different from an ISAPI filter). Also from deeper investigation one can see that sharepoint uses what is called a "Wildcard application map" which actually forces all requests to be processed by ASP.NET first.

The problem is I cannot figure out what the author intended to convey to me. Also the analogy to IIS, I can see the point but I still have to figure out what is that special thing about SharePoint that lets it control things like "application pool accounts" instead of having to use IIS. I am not sure about this point but is there more to it than the right permissions and some system calls done through ASP.NET?

Back to reading...