On Wednesday 08 October 2003 06:46 pm, Frank van der Linden wrote:
> On Wed, Oct 08, 2003 at 06:41:37PM +0000, Charles M. Hannum wrote:
> > 2) A controller+drive older than that will read all-1s.  Therefore it
> > will fail the 0 test and continue polling.  This is completely harmless. 
> > Because the drive also is too old to support the slave register
> > shadowing, this test would not work for it anyway even if it read the
> > main status register.
>
> Is that guaranteed? This is fine on i386, but there are architectures
> out there, like macppc, that will fault if you read a non-existent I/O
> address.

How do you plan to plug a 20-year old full-length ISA controller into a 
PowerPC Mac?