Compilation question 64bit, 32 bit

[Miroslav Lachman]

Alexander Leidinger wrote:
> Quoting Jose Amengual <jose.amengual at gmail.com> (from Thu, 16 Oct 2008  
> 08:43:15 -0300):
> 
>> Hi Guys.
>>
>> The other day I install a server with jails with FreeBSD 7 32 bit in  
>> a 64 bit capable processor.
>>
>> After I install I start wondering some things that I point out here :
>>
>> Any benefit to install 64 bit vs 32 bit with the purpose of use jails ?
> 
> 
> It depends. If you want to use more than 4G: yes.
> 
>> Can I install a 32 bit FreeBSD and create 64 bit jails ? ( using  
>> ezjail or downloading the full 64 bit source to create the jail ).
> 
> 
> No.
> 
>> Can I install 32 bit FreeBSD and then made a make world and change  it 
>> to 64 bit ? ( is recommended ?)
> 
> 
> IIRC this depends upon your FreeBSD version. I think in CURRENT  there's 
> code which supports that now. No guarantees.
> 
>> Can I install a FreeBSD 64 bit and create 32 bit jails ?
> 
> 
> Sort of. You can install a 32bit world into the jail and make sure  
> 32bit support is activated in the kernel. The 32bit programs will then  
> run just fine in the jail (but 64bit ones should run fine too). It's  
> the same way as you can run linux programs in a jail.

Do you mean installing whole 32bit world instead of 64bit, for example 
from ftp.freebsd.cz:/pub/FreeBSD/releases/i386/7.0-RELEASE/base/ or just 
/lib32 /usr/lib32 libraries?
Will it be possible in this (32bit) jail to install ports marked as arch 
i386 only, or some voodoo is needed to trick the ports system?
What do you mean by "32bit support in kernel"? Is it just options 
   COMPAT_IA32 as is in amd64 GENERIC or anything else?

I am interested in running 32bit ports on amd64 bit machine.

Miroslav Lachman