Do 32 bit apps run in x86_64?

Aragorn wrote:
> On Monday 26 October 2009 02:34 in comp.os.linux.misc, somebody
> identifying as Todd wrote...
>
>> Hi All,
>>
>> Just out of curiosity, do 32 bit apps run in
>> 64 bit Linux? Or, must they be ported to 64 bit
>> before they will run? What about 32 bit RPMs?
>
> 32-bit compatibility is enabled by default in virtually all
> distribution-supplied binary kernels. Such 64-bit distributions are
> typically referred to as "multilib", which means that they contain both
> the native 64-bit libraries and a set of 32-bit libraries for 32-bit
> executables that require them.
>
> That said, there were some problems in the past with certain
> (proprietary) browser plugins that were only available as 32-bit
> software, and which you could thus only use in a 32-bit browser, but
> due to multilib you could install such a browser on an otherwise 64-bit
> platform.
>
> These problems however are now largely a thing of the past due to
> the /nspluginwrapper/ project, which allowed the use of 32-bit browser
> plugins in a 64-bit browser, and due to the fact that most of those
> formerly 32-bit-only plugins have in the meantime been ported to
> 64-bit.

You still cant get firefox 3.5 precompiled for 64 bit.

Or if you can, tell me where. I compiled mine from source..

>
> The above all said, and thereby confirming that 32-bit applications can
> be made to work in a 64-bit GNU/Linux system, using natively 64-bit
> applications would probably yield some benefits. In some cases,
> performance might improve if the application was built for a 64-bit
> environment.
>

I needed 3.5.3 because people use it, and there are differences in
rendering colors between 2.X and 3.5 - in particular it interprets
(gamma correction?) in images. Since my wife does a bit of graphics
design,she wanted to know why colors didn't match on 3.5.3 when they did
on 2.X..

So 3.5.3 wqas needed and for SOME reason the 32 bit stuff did not work
on my 64 bit platform. IIRC some specific 32 bit mozilla libraries were
not there. But I've slept since then, so I cant remember.




> There are of course people who claim that 32-bit performs better, but
> they usually base their findings upon 32-bit applications that have
> simply been recompiled for 64-bit without that the actual code had been
> adapted. There is more to optimizing than just the compiler level.
> Code that was specifically written with 64-bit implementation in mind
> is much more efficient than code that was written with 32-bit in mind
> and then simply recompiled to 64-bit.
>
> Hope that answers your question adequately.
>
64 bit definitely performs MUCH better for graphic intensive stuff. My
real reason for using it.

I cant say other apps show much improvement.

>>>>> "The" == The Natural Philosopher <tnp RemoveThis @invalid.invalid> writes:

The> And be prepared to drop back to a 32 bit install if some key
The> applications imply wont work.

That's not necessary. A 32-bit chrooted environment residing in an
otherwise 64-bit installation would suffice. I've used this method to
run Firefox to get the Flash and Java plugins to work, before 64-bit
versions of the plugin became available.

Another possibility is to set up a virtual machine (e.g. using Virtual
Box OSE) to run a 32-bit OS to run those 32-bit operations.


--
Lee Sau Dan §õ¦u´° ~{@nJX6X~}

E-mail: danlee RemoveThis @informatik.uni-freiburg.de
Home page: http://www.informatik.uni-freiburg.de/~danlee