What are the advantages and disadvantages of ISAPI?

Answer 1

The advantages of using ISAPI is that ISAPI extensions processes are tha same as ASP or Active Server Pages but they are much more quicker in communicating because of the compiler code. If you compare them to CGI, ISAPI processes every request through isolated threads and synchronized work items instead of building unique process for every request. This helps it make more resourceful use of systems.

There are drawbacks to ISAPI also. The interface is not supported by the associated services as is the case with ASP and COM and some of the functionality need to be developed manually in order to allow it for session state maintainance. Hope this helps.