from
The Free On-line Dictionary of Computing (8 July 2008)
bus error
BERR
SIGBUS
<processor> 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)