[Wylug-discuss] Linux on Intel 64-Bit Xeon

[Dave Fisher]

On Thu, Jun 23, 2005 at 12:33:11PM +0100, Phil Foxton wrote:
> On Thu, 2005-06-23 at 12:15 +0100, Dave Fisher wrote:
> >    1. Which Intel 64-bit architecture is a 'Dual 64-Bit Xeon'?  
> >    
> EM64T
> >    As I understand it, Intel has two 64-bit architectures (one that is
> >    and one that isn't 32-bit compatible).  Am I right about this?
> > 
> Not that I am aware of, but it might be worth asking Dell if the box is
> a EM64T arch. box. AFAIK (and I might be wrong so don't quote me) Intel
> started down the route of 64 with a completely new design (Itanium) but
> it was NOT backwardsly compatible with X86 so they ended up licensing
> the X86_64 arch. from AMD.

Thanks Phil, bit I am still a bit confused.  

  1. Is EM64T Itanium or X86_64?

  2.  Isn't AMD's X86_64 capable of running 32-bit x86 code, and
  therefore "32-bit compatible"? Whereas there never was a 32-bit
  version of Itanium, so it its "32-bit _in_compatible"? What have I
  failed to grasp?

Dave