OR> A fatal failure in the execution of a {machine language} instruction resulting from the {processOR} detecting an anomalous condition on its bus. Such conditions include invalid address alignment (accessing a multi-byte number at an odd address), accessing a physical address that does not cORrespond to any device, OR some other device-specific hardware errOR. A bus errOR triggers a processOR-level exception which Unix translates into a "SIGBUS" signal which, if not caught, will terminate the current process. (2000-04-04)