What does cgi stand for? What are the uses of CGI in iis? How does it configure in iis 8? What is FastCGI?

CGI stand for Common Gateway Interface.It is used by webserver to pass web user request  to application server and process and give back the output.it is a part of http protocol 

To enable go to control panel>Turn on windows features>go to IIS>World Wide Web services>Application Devolopment Features> Select the check box CGI>

fast cgi is a binary protocol for interfacing interactive programs with a web server.