Re: amd64 and dpkg and so

[Martin Jungowski <jungowsk@in.tum.de>]

That is so true. The CPU is capable of running 32-bit software in 64-bit
mode as fast as in native 32-bit mode - whatever you do, you HAVE to be
able to run standard 32-bit software otherwise nobody's going to use the
64-bit Linux.
Mind you, not everything is available as 64-bit port yet and not
everything will be available as 64-bit port for a long time.

So yes, you're absolutely right. Not being able to run 32-bit software
in 64-bit mode is not very clever however given the CPU, I don't think
it's possible to restrict a 64-bit distro like that - how would you even
want to do that, the kernel and all the libs and everything can be
64-bit so the CPU is going to run in Long Mode (that's what AMD named
the 64-bit mode) but any 32-bit code will still run, I don't see a way
to stop it from running

Martin




On Thu, 2003-08-28 at 12:20, Roland Fehrenbacher wrote:
> >>>>> "Martin" == Martin Jungowski <jungowsk@in.tum.de> writes:
> 
>     Martin> On Thu, 2003-08-28 at 10:43, Roland Fehrenbacher wrote:
>     >> Fully agreed. A pure 64bit distro would be nothing more than an
>     >> academical exercise at this stage and the foreseeable future with little
>     >> practical value and even less real users. 32 bit binaries will need to
>     >> run on these machines for a long time. Please don't waist resources for
>     >> this.
> 
>     Martin> Oh I don't think so. The AMD Opteron is a lot faster in 64-bit than
>     Martin> in 32-bit. Not only does it have eight additional GPRs but also the
>     Martin> XMM-Registers (aka SSE). During my benching, every single 64-bit
>     Martin> test was faster than the same software compiled for 32-bit -
>     Martin> sometimes more than 20% faster in 64-bit
> 
> I fully agree with what you say about the Opteron. But it doesn't contradict
> what I said. Every user of such a system will more than likely also need or
> want to run a 32bit binary on such a machine at some stage, and it is just too
> restrictive not to be able to do that. It is clear that you want to run 64bit
> whenever you can, but you won't always be able to.
> 
>