Hello,

some times ago I sent a little script that extracts and installs
i386 libs to provide i386 compatibility on x86_64 systems.

I have installed a set of 32 i386 machines (dual opterons) which
are used in production in our farm.
I also installed an additionnal machine in x86_64 with the
full i386 libraries.

Here is some notes about that, if other people wanted to do the
same :

First, many RPMs only provides libraries, not symlinks. And in
some cases it is not always possible to guess what symlinks
should be created. It is so difficult to make a full automatic
process for that. I had to do some minor job by the hand.

Second, some x86_64 RPMs do not exists in the i386 repository,
or with a different version number. You have to make the choice
to ignore it or install the older/newer one. Please remember that
only libs should be installed. No executable/config file sould
be copied, as they would overwrite existing ones (from the x86_64
installation).

Third, be sure to add the new library pathes (i386) in /etc/ld.so.conf
so that all will be found be the dynamic linker (in particular 32 bits
versions of X11 libraries).

Fourth, do not forget the x86_64 package for i386 libs (something
like *32*.x86_64.rpm), which gives the glibc).


At last, I get a 64 bits system with the full set of 32 bits libraries.
I added it in the production farm, and jobs run without any problems.
By the way we use openAFS, and of course the sysname for the 64 bits
machine is the same than for the 32 bits machines.


So the conclusions :
- it is possible to have a 64 bits system (for performance reasons) with
a full 32 bits set of libs (for compatibility). At this time we do not met
any problems (but it is for batch, not for interactive machines... users
can be _very_ more inventive and discover bugs...)
- installing the 32 bits libraries "by the hand" is not a good thing for
several reasons:
   - it is complicated
   - we can miss some things which are done in the post-installation scripts
   - we do not have a way to manage updates properly

For the first point it is a good thing, because we can have a smooth
evolution between 32 bits and 64 bits systems.

For the second point, the only way should be to use 'rpm' to handle the
i386 RPMs in the same way than the x64_64 ones.
I think I will have a look to the current 'rpm' sources to see if this can
be integrated...

Regards,
--
Yannick Perret