In 1986, Linda and Tony Sherzer entered their program Bebe into the 4th World Computer Chess Championship, running it on "Chess Engine," their brand name for the chess computer hardware made, and marketed by their company Sys-10, Inc. By 1990, the developers of Deep Blue, Feng-hsiung Hsu and Murray Campbell were writing of giving their program a 'searching engine,' apparently referring to the software rather than the hardware.