Re: Concerns about AMD64 port
On Thu, Feb 05, 2004 at 05:02:53PM +0100, Goswin von Brederlow wrote:
> John Goerzen <firstname.lastname@example.org> writes:
> > > Our big goal is to support A) pure 32bit i386, B) mixed 32/64 bit
> > > i386/amd64 and C) pure 64bit amd64 userspace.
> > If a pure 64bit userspace is the goal, why does the AMD64 ports page say
> > such a thing is "academical and of little use"?
> Because the 64bit only userspace will be the mixed userspace with the
> 32 bit stuff missing. It will still be the 64bit part of the mixed
> systems. That means e.g. that libs are in /lib64/ and /usr/lib64/.
Uhm, that strikes me as solely a rhetorical device. A mixed userspace
without the 32-bit stuff is, by definition, a pure 64-bit userspace :-)
In fact, the only thing at all that I can see that is different about
this than any other pure 64-bit system is the names of the lib
directories. The naming of the lib directories has no bearing on
whether a platform is 64-bit or not. I could build a pure 64-bit AMD64
Linux distro that calls it /Library and it will still be 64-bit.
Plus, it's trivial to make changes to autoconf and debhelper that would
probably get 90% of the packages to put their libs in the right place.
> Developing a standalone 64 bit system thats incompatible to the mixed
> system is work wasted.
I am not suggesting that.
> > B seems like the toughest thing to accomplish. Wouldn't it make more
> > sense to get C done first, and then once the 64-bit userspace is
> > functional, add on the 32-bit emulation?
> No, you would have to throw it away to change to a mixed mode. The
> problem is getting the 64bit stuff out of the way of the 32 bit stuff
> and not compiling for 64 bit.
Why would you have to throw it away? If the only problem really is the
/lib64 thing, that's not hard to fix.
> > > For some crucial things likes libc6 it doesn't look like we can get
> > > rid of the 32bit flavour though. But apart from a bit of bloat here
> > Are you saying that libc6 cannot build as a 64-bit package?
> No, it just looks to complex to build a standalone 64 and 32 bit
> package that also work together. Currently the 64bit package depends
> on the 32 bit package. For something as essential as libc6 thats fine
> for now.
Why is that? that's just weird.
> /lib/ -> lib64/,... , one arch -> multiarch
So we put everything in /lib64 now, and add on /lib later.
> Solving the problem just for amd64 by ignoring the 32bit support would
> be a hell of a lot easier but work wasted when multiarch replaces it.
I still don't buy that. If the problem really is the location of libs,
that is not a tough nut to crack for a single arch.