AberMUD /ˈæbərmʌd/ was the first popular open source MUD, named after the town in which it was written, Aberystwyth. The first version was written in B by Alan Cox, Richard Acott, Jim Finnis, and Leon Thrane based at University of Wales, Aberystwyth for an old Honeywell mainframe and opened in 1987. Alan Cox had played the University of Essex MUD1 written by Roy Trubshaw and Richard Bartle, and the gameplay was heavily influenced by MUD1. In late 1988 AberMUD was ported to C by Alan Cox so it could run on UNIX at Southampton University's Maths machines. This version was named AberMUD2.