On Wed, 3 Mar 1999 12:07:00 -0800 (PST) 
 Matthew Jacob <mjacob@feral.com> wrote:

 > > Well, a NetBSD/alpha process will get SIGBUS'd if it does other SIGBUS'able
 > > access :-)  i.e. accessing a nonexistent (vs. unmapped) memory location.
 > 
 > Shouldn't that be a SIGSEGV?

If the process accesses an address that is unmapped, it gets a SIGSEGV.

If the process accesses an address that is mapped, but is non-existent (i.e.
there is no underlying memory, device, etc.), then it gets a SIGBUS.

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>