A student at University of Berkeley, called Ken Arnold, had designed a library of C functions which allowed programs to do cursor addressing, which means that the programs could put a character at a specific location on the computer screen. It was not "real" graphics, but you could use letters, numbers and other symbols to simulate pictures. The library was called curses .
Michael Toy and Glenn Wichman, two students in University of Santa Cruz, California, experimented with curses library. They both had enjoyed playing Adventure which was the first text adventure game. After making some simple games with curses, they began to write a graphical adventure game. Michael Toy did most of the programming and Glenn contributed ideas to the project and coined the name "Rogue".