# Xeon with EM64T which kernel processor family?!?!

## mark4gentoo

Hello,

i have emerged gentoo-sources and got the linux-2.6.14-gentoo-r2 kernel.

I have a dual processor xeon box with EM64T. So I want my kernel to do 64 Bit.

Looking at the processor family settings tells me that there are settings for opteron etc... but nothing for my xeon with EM64T. Only for a "normal" xeon, which goes togethter with pentium 4.

So which settings do I have to use in kernel configuration in order to get 64 bit working?!?!

Thanks a lot!

Mark

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## ewan.paton

x86_64

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## ewan.paton

arg should also have pointed you to the amd64 install guide, em64t is a mostly compatible {1} version of amds 64 bit extention, same rules as amd apply you cant just upgrade from 32 bit to 64 bit etc.

{1} i think intel initialy forgot a few bits or amd added them to late to make it into the presscots 1st design

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## mark4gentoo

So I have to follow the AMD64 handbook in order to install my xeon with em64T.

But it's an intel and no amd64... Are there any shortcomes because of this?

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## ewan.paton

no its just called amd64 on these boards cause amd invented it, intel have binary compatible implementaition called em64t, much the same way as intel x86 pentiums and amd cpus were compatible. there are the odd minor incompatibility glitch but nothing to worry about unless you do really  low level programing.

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## mark4gentoo

hmmm, will there ever be a special release for xeons with em64T. Or will there always be only AMD64 and xeon users have to use this?

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## drescherjm

I would doubt it because the differences are so small and if needed they could be handled by a use flag or different setting in cflags.

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## Carlo

 *mark4gentoo wrote:*   

> hmmm, will there ever be a special release for xeons with em64T. Or will there always be only AMD64 and xeon users have to use this?

 

This is just a name, stemming from the fact that the x86 64-bit extension is made by AMD. Intel won't use it of course, because of marketing reasons. You can safely use amd64. Afaik early em64t chips were slightly incompatible, though.

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## rpodgorny

...isn't there a way to move live x86 system to amd64 (without reinstalling)?

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