Am I 32-bit, or 64-bit?

[Michael ODonnell]

> In the meantime...  is there any possible downside of having
> a 64-bit kernel in a 32-bit userspace?  Everything -- drivers,
> camera, apps -- seems just ducky.

I've seen instances where 32bit apps and libraries disagreed
with some 64bit drivers about the layout of the data structures
that get passed back and forth (earlier versions of the FireWire
driver versus libraw1394 come to mind) but in general, stuff
should Just Work.  The 32bit binaries execute natively (ie.
no emulation or translation overhead) and I think by now most
kernel code has been taught to do the right thing when it
sees that the current process is a 32bit binary.  One upside
is that the 32bit processes are able to address an extra Gb
of memory since the kernel no longer claims the top 1/4 of
their address space...