ISAPI Support

Definition
Short for Internet Server API, an API for Microsoft's IIS (Internet Information Server) Web server. ISAPI enables programmers to develop Web-based applications that run much faster than conventional CGI programs because they're more tightly integrated with the Web server. In addition to IIS, several Web servers from companies other than Microsoft support ISAPI.

There is a great deal of information on the web about ISAPI. Here are a few links that will help:

Microsoft - this could change (the site is continually being updated)
 
15 Seconds - worth looking at
 
The ISAPI Developer's Site - covers it all (just about)
 
DataWeb - ISAPI support page
 
Webopedia - ISAPI section
 
Webcompare - ISAPI with PERL
 
CodeGuru on Earthweb - good site of coding

Execution
ISAPI Alias is the only directory where ISAPI extensions will be executed. If an ISAPI dll is placed in another directory, and is executed, it will prompt the user to download the dll like it was any other binary file.

Use /scripts/ for an ISAPI alias (you can use whatever you want). Say there is a directory c:\isapi\dll that had a file mydll.dll in it. You would set the alias to /scripts/ and the path to c:\isapi\dll. Then when the url of /scripts/mydll.dll is requested, mydll.dll will be handled as an ISAPI extension.