Apache is a free and open-source cross-platform web server software.
Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Debian is a Linux software which is a free open-source software.
Mod_fcgid is a high performance alternative to mod_cgi or mod_cgid, which starts a sufficient number instances of the CGI program to handle concurrent requests, and these programs remain running to handle further incoming requests.