+---------+ (1)Request +--------+ +--------+ | |-------------->| | | Server | | Web | | Web |-----------| File | | Browser | | Server |(2)Retrieve| System | | |<--------------| | +--------+ +---------+ (3)Reply +--------+
+---------+ (1)Request +--------+ (2)Input +---------+ | |-------------->| |---------->| | | Web | | Web | | A "CGI" | | Browser | | Server | | Program | | |<--------------| |<----------| | +---------+ (4)Reply +--------+ (3)Output +---------+ | | +--------+ | Server | | File | | System | +--------+
+---------+ (1)Request +--------+ (2)Input +---------+ | |-------------->| |---------->| | | Web | | Web | | A "CGI" | | Browser | | Server | | Program | | |<--------------| |<----------| | +---------+ (4)Reply +--------+ (3)Output +---------+ | | | +--------+ | | | Server | | +---------| File |--+ (2,3)Retrieve | System | +--------+