[vox-tech] what is a bus error

[Peter Jay Salzman]

thanks for the answer -- the only time i've seen bus errors (i only use
x86) is netscape, but back in the 4.x days before NS6, opera or mozilla
came onto the scene.  if i went back/forth in the browser too quickly,
netscape would barf and (if netscape was run from an xterm) i'd see "bus
error".

but to add support to your email, most of what i've seen on google was
from people on sparc architectures, not x86 people.

pete


begin Matt Roper <matt@mattrope.com> 
> In my experience, a bus error is caused by the same type of problem as a
> segmentation fault (i.e. out of bounds memory access).  I once had an
> out of bounds memory access in a program I wrote and found that
> depending on how far out of bounds my access was, the error message
> would change between "segmentation fault" and "bus error" (this program
> was running under Solaris on a Sun machine).
> 
> I'm not certain why one message appears sometimes and the other at other
> times, but one possibility (a wild guess) is that since some
> architectures use part of the address space to represent IO devices
> instead of memory locations, the "Bus Error" message will occur if the
> illegal memory location falls in the IO device address range and a
> "Segmentation Fault" will occur if the illegal memory location falls in
> the memory range.  FWIW, I've never seen a bus error message on x86
> Linux, so maybe it doesn't happen on the x86 architecture or maybe it's
> just triggered differently.
> 
> 
> Matt
> 
> On Mon, Jan 07, 2002 at 04:18:57PM -0800, Peter Jay Salzman wrote:
> > i did a google search, and found alot of conflicting answers.  some of
> > them seemed to indicate that the precise definition of bus error is
> > architecture dependent, but i find that hard to believe.
> > 
> > i know what a segmentation violation is.
> > 
> > but what exactly is a bus error?
> > 
> > can anyone write a hello world type program that demonstrates barfing
> > from a bus error?  i found some code that purported to produce a bus
> > error on a sparc, but it didn't barf under linux.
> > 
> > pete
> > 
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