Versions were introduced on the MS-DOS platform in the late 1980s, mostly using FORTRAN compilers capable of compiling the original code. Later versions converted the FORTRAN to the C programming language, either by hand or using automated tools. These versions were often limited by the platform's resources. Modern versions run on a wide variety of platforms. Modern programs usually have a separate graphical user interface (GUI) that allows the user to draw and edit the antenna. When that is complete, the GUI converts the design into the NEC-2 deck file format and runs NEC-2. The GUI then parses NEC-2's output and graphically displays the results.