[CentOS] Installing CentOS 4.1 on IA64 -- Decoder Ring: AMD64/x86-64, EM64T/IA-32e, IA64/IA-64

Tue Aug 9 20:03:38 UTC 2005
Bryan J. Smith <b.j.smith at ieee.org>

David Johnston <david at littlebald.com> wrote:
> Lim, also, make sure that the machine you're installing on
> is IA64 and not AMD (which is x86_64).  One of our guys
made
> that mistake last week, and wasted a lot of time trying to
> figure out why it was panicking.

Yep, I've now caught at least 2 people on other lists
installing IA-64 on Dell's new EM64T systems.  I guess the
influx of Dell desktops with EM64T is causing a lot of
confusion.

[ SIDE NOTE:  I'm sure the fact that Debian doesn't list
AMD64 as a port on its ports page (because it's not an
official port release yet, just in test) is also causing
people to assume IA64. ]

Here's the typical names of Linux ports as they match up to
products:  

Vendor  Common  Official ISA       Products
------  ------  -------- --------  -----------------
AMD     AMD64   x86-64   x86-64    Athlon/64/Opteron
Intel   EM64T   IA-32e   x86-64**  Pentium-4/Xeon-MP
Intel   IA64    IA-64    IA-64     Itanium/2

AMD64 and EM64T are essentially the same, and support the AMD
x86-64 (**NOTE: what Intel calls IA-32e, a slight subset of
x86-64) instruction set architecture (ISA).  In a nutshell,
Linux/AMD64 aka Linux/x86-64 releases and packages (e.g.,
.x86_64.rpm) run on _commodity_ Athlon64/Opteron as well as
newer Pentium 4/Xeon MP systems.

IA64 is _completely_different_ and only offers a subset of
x86 compatibility in hardware (and Intel has even moved to
using Digital's former FX!32 software because it's faster). 
IA-64 products are _Itanium_, and _never_ Pentium series.


-- 
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