Hello,
As far as I know and in most cases there is not much difference in speed between
32 and 64 bits applications and for most users a 64 bits kernel running 32 bits
applications (as Knoppix 6.5 allows you to do right now) is probably good enough.
A key advantage though for the 64 bits kernel is that it allows Linux to see
more than 4GB of memory which is a big advantage for most new systems
(even though compiling a 32 bits kernel with PAE would actually do the same)
An other key
advantage to have a 64 bits kernel is that it allows you to run
either 64 or 32 bits virtual machines guest operating systems. A 32 bits kernel
will only allow you to run a 32 bits guest OS. So a 64 bits kernel is a big bonus.
As a side note I still have trouble installing the vmware tools (HGFS) with the 64 bits
kernel and I would appreciate some help if someone got it working on Knoppix 6.5.
Even though a "pure" 64bits Knoppix would be a nice boot option (as Kanotix)
it is quite simple to recompile in 64 bits mode the few applications (or server daemons)
for which you need the best performance possible. As an example you only need to install
"amd64-libs-dev" to Knoppix 6.5 (obviously started with the 64 bits kernel)
to get all you need to compile 64 bits binaries. Try from a root console:
"apt-get install amd64-libs-dev" and then compile your 64 bits binaries
using the "-m64" gcc option and you can get all the
benefit of a 64bits processor
for the few applications that you need to run as fast as possible.
This is by the way a nice way to bootstrap a "pure" 64 bits version of Knoppix
if you really feel the need for one (this was your original question).
It is indeed interesting to verify as an example that the "pi" benchmark runs effectively
twice faster in 64 bits mode than in 32 bits mode (http://h2np.net/pi/pi_quick_start.tar.gz).
It is also good to know that 64 bits binaries are also twice larger than 32 bits binaries,
which means the need for a larger mass storage. This is probably also a good reason for
Klaus to keep 32 bits binaries on his quite well packed and almost full CD & DVD images.
Hope this helps,
Gilles
>> >I rather hope that Knoppix will be available in "32-bits for quite a
>> while" indeed! Most of the machines I run Knoppix on are 32-bit
>>
machines.
>>
>
> I explicitly stated that 32 vs 64 bits was not the subject here.
> Furthermore, it
will not be difficult to deliver both 32 and 64 bits in
> the same package, just two different compressed images to choose
> between, analogous to the way we can choose between 32 and 64 bits
> kernels when booting Knoppix today. From my own very modest and
> superficial testing of 32 vs "pure" 64 bits on ordinary actual hardware
> (like the I5-430M processor), the difference is not huge today with
> ordinary user space programs.
>
> So making this an important development issue today isn't very fruitful,
> I think.
> There is, however, no good reason why Knoppix should be confined to
> 32-bits, if volunteers take the (mostly administrative) job of making a
> 64-bits version for each release. Remastering-wise, 32 and 64 bits
> versions should behave similarly.
>
> As for the approach, I think I may try out starting from a basic 64-bits
> Debian
and see how it works out.
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