[2][3][4][5] McCool was the author of the original NCSA HTTPd web server,[6] later known as the Apache HTTP Server, and until Apache version 2.2, httpd.conf files as distributed contain comments signed with his name.
He wrote the first version while he was an undergraduate at the University of Illinois at Urbana–Champaign, where he was working with the original NCSA Mosaic team.
[1] One of Robert McCool's many contributions was in drafting the initial specification of the Common Gateway Interface (CGI), in collaboration with others on the www-talk mailing list, and providing a reference implementation of CGI in version 1.0 of the NCSA HTTPd web server.
[7] The CGI specification, introduced in December 1993, turned out to be a key element in making the World Wide Web dynamic and interactive.
Later, at Stanford University, he co-authored the TAP[8] and KDD systems for automatic augmentation of human-generated web content.