Re: AMD64 and lib64

[Kevin Rosenberg <kevin@rosenberg.net>]

Martin Michlmayr - Debian Project Leader wrote:
> I talked to Chris Yeoh of the Linux Standards Base (LSB) recently and
> mentioned that the current port uses /lib rather than /lib64 (the
> latter is required by the LSB).  He strongly advised against using
> /lib plus /lib64 symlinks, and he kindly elaborated the problem below.
> How do you address these concerns and how much work would it be to use
> /lib64 (libtool could be patched to use that path by default, but how
> many libraries don't use it?).

Personally, I like the so-called biarch (/lib64 for 64-bit libraries
and /lib for 32-bit binaries). I run SuSE on two of my systems so I
have very good 32-bit and 64-bit binary compatibility. These are the
only non-Debian systems on my network. I run some non-free 32-bit
binary packages on them as well as Oracle's AMD64 binary.

I'd like to see Debian support biarch. The initial Debian AMD64 port
was biarch. However, due to the effort to modify each source package
to use /lib64, only a small fraction of the source packages in Debian
were compiled for biarch. I understand that the biarch packages are
still on Alioth. I've heard people say that /lib64 is ugly. Perhaps my
sense of asthetics isn't as keen or narrow, but it does not bother me
and it certainly solves the issue of binary compatibility.

>From watching the activity on #debian-amd64, it appears that biarch is
effectivley dead and has been so for a number of months. I'm not aware
of anyone currently working on biarch. I believe one of the reasons
for its death is that the dpkg maintainer wasn't interested in working
on supporting biarch until the purported "dpkg 2.0" was developed
sometime after sarge ships.

I am running the pure64 Debian port in several chroots and it's
working fine. For an AMD64 system, I think the Debian pure64 port is a
better choice than running i386. As others have stated, you can still
run 32-bit binaries in a Debian i386 chroot. Obviously, this is not as
seamless or integrated as a biarch system. Yet, I still think the
Debian pure64 port is a win compared to running i386.

You likely know more about multiarch that me. But the consensus on
#debian-amd64 seems to be that multiarch is a more robust replacement
for biarch. It seems there are people who are willing to work on
multiarch, but not on biarch.

My thoughts in summary: 
 - biarch is very good, but I don't forsee anyone developing it for
   Debian. I'd like to be shown to be wrong on this, so if someone
   wants to work on this -- this is a good time to speak up.
   If you really need a biarch system, it's easiest to just run a
   different operating system.
 - The debian pure64 port runs well and is a better OS for an AMD64
   system than the i386 distribution. Some people will need a 32-bit chroot
   for compatibility. I've had some, but not complete, luck with the
   ia32-libs package for compatibility with 32-bit binaries
 - multiarch is a transition approach for pure64 for running 32-bit
   and 64-bit binaries. However, I'm not aware it will solve issues
   with running 32-bit binaries that are compiled for the LSB.
 
My recommendations:
   Unless one or more people come forward and say they will work on
   supporting biarch, I think the pure64 bit port should be accepted
   into sid as the best solution that Debian can provide.

-- 
Kevin Rosenberg
kevin@rosenberg.net