[svlug] Running 32-bit apps under 64-bit kernel

Rick Moen rick at linuxmafia.com
Tue Jan 5 21:56:54 PST 2010


Quoting Alan DuBoff (aland at softorchestra.com):

> I thought it was possible to run 32-bit apps under the 64-bit 
> kernel...but it seems Adobe Acroread wants to have a 32-bit ELF 
> file.
> 
> Is it possible to run AcroRead under the 64-bit kernel?
> 
> I'm running Lenny (Debian), if that matters.

Specifically, you need to be able to run _binary_ 32-bit applications 
on x86_64-architecture Debian.  That means it's not possible to 
tweak source and recompile to make it resolve its lib calls
to /usr/lib32 or /usr/lib/i486-linux-gnu , because the binary is 
already set to ask the dynamic linker for the bare sonames, resulting in
them finding the distro's /usr/lib libs, which are for x86_64, hence
incompatible, /usr/lib being a symlink to /usr/lib/x86_64-linux-gnu
or something like that.  (That's my understanding.  If wrong in some
details, my apologies.)

If you want to read up on the background of this tale of woe, here are
two relevant Web searches:

   debian biarch
         That'll find information about the original suggestion about
         how to deal with this problem systematically.
   debian multiarch
         That'll find information on what I believe is the officially
         approved approach that is being implemented by Debian and
         Ubuntu, which will get you links like these:
         http://wiki.debian.org/multiarch
         https://wiki.ubuntu.com/MultiarchSpec

Last I heard (July 2009), dpkg needed some additional work to properly
support all that multiarch stuff.


But you just want to run Acroread.  Maybe you want just a simple IA32
chroot:   http://ornellas.apanela.com/dokuwiki/pub:multiarch

Note:  Web page is _not_ about multiarch as the term is referred to in
standard discussions of the issue in Debian/Ubuntu circles, but rather
refers to setting up a 32-bit chroot.

My understanding is that RHEL / CentOS / OpenSUSE / SLED/SLES / Gentoo
all went with the biarch approach.


Incidentally, Acroread is why my DNS nameserver has since 2005 declared
itself authoritative for the "remoteapproach.com" DNS domain, so that
users of my DNS who execute Adobe Acrobat Reader v.7 and up aren't being
spied on by Adobe's business partner Remote Approach.  See:
http://lwn.net/Articles/129729/ 

I don't know if Remote Approach is still in business, but, if Adobe's
software has been known to spy on you in the past, the most reasonable
expectation is that it should be expected to do so in the future --
which is why I personally think Evince, xpdf, etc. are to be preferred
(but choose your own poison, of course).

-- 
Rick Moen              "Having the right word is much more satisfying than just 
rick at linuxmafia.com    sleeping around with any old word that comes along."
                                                            -- FakeAPStylebook




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