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Re: which version for intel chipset 64bit



On Wed, 9 Feb 2011, Bob Proulx wrote:


Bret Busby wrote:
The web page at http://www.debian.org/ports/amd64/ states
The port consists of a kernel for all AMD 64bit CPUs with AMD64
extension and all Intel CPUs with EM64T extension, and a common
64bit userspace.

Thus, from the Debian official documentation, it is made clear that
Intel 64 bit CPU's that do not have the "EM64T extension" (whatever
that is and does), have no 64 bit version of Debian Linux available
for them.

Intel calls their AMD64 architecture EM64T.  It is Intel's name for
it.  For all practical purposes they are the same thing.  However
there may be different bugs in them since they were implemented by
different design teams.  But in particular this is not IA64 which is a
completely different 64-bit architecture but one that is often
confused by users with AMD64.

Therefore, it is not simply an issue of whether a CPU is a 64 bit
CPU and is therefore compatible with Debian 64 bit Linux; it is made
clear from the official Debian documentation, that only 32 bit
Debian Linux is available from Debian, for all 64 bit CPU's that do
not have the "EM64T extension",

No.  You are reading too much into that somewhat less-that-perfectly-
worded document.  Don't cause that much pain for yourself.

It is saying that all AMD manufactured cpus of the AMD64 architecture
and all Intel manufactured cpus of the EM64T architecture are
supported.  By saying it that way it is allowing for AMD64 specific
opcodes and for EM64T specific opcodes (I recall there are a very few)
and the common subset between them (almost all it) and saying that
each of those almost the same but very slightly different
architectures are supported.  They may be slightly different but for
all practical purposes for you as a user of them you can think of them
as being the same.

and thus, without knowing whether a particular 64 bit Intel (or
compatible) CPU is compatible with the Debian Linux 64 bit version,
there is no point in trying to install that version.

No.  It doesn't say that at all.

If it is a 64-bit AMD cpu then you can install the 64-bit amd64 port.
If it is a 64-bit Intel cpu and /not/ IA-64 then you can install the
64-bit amd64 port.  If it is a 64-bit Intel cpu and IA-64 (rare, found
in high end server hardware) then you can install the IA-64 port.

I believe that, in the circumstances, as Debian has made it clear
that a 64 bit version of Debian Linux, is not available for 64 bit
CPU's, other than a particular subset of 64 bit CPU's, to inform the
public as to what 64 bit CPU's are limited to a 32 bit version of
the operating system, is a reasonable expectation.

(I am sure you are going to hate that I chose that particular
paragraph to quote in my response.  :-)

You are making it too difficult.  I can't think of any 64-bit capable
cpus that are not 64-bit capable.  Really! :-)

The normal question is how can you tell from a 32-bit system, such as
a live cd boot or some such, whether the system is 64-bit capable?
The answer to that question is to look at the cpu flags and see if the
"lm" flag is present.  That is the long-mode flag and if present
indicates that the cpu is 64-bit capable.

 $ grep --color '\<lm\>' /proc/cpuinfo

If that flag is present then you are good to go for a 64-bit system.

Bob


Does that mean that, from

"
:~$ cat /proc/cpuinfo
processor	: 0
vendor_id	: AuthenticAMD
cpu family	: 15
model		: 44
model name	: AMD Sempron(tm) Processor 2800+
stepping	: 2
cpu MHz		: 1600.224
cache size	: 256 KB
fdiv_bug	: no
hlt_bug		: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt lm 3dnowext 3dnow up pni lahf_lm ts ttp tm stc
bogomips	: 3204.10
"

this system will run 64 bit Debian, and other 64 bit OS's?

And, that the CPU (if not the BIOS) can work with 8GB of RAM?

(This is different to the I3 system that I particularly wanted to know whether I should try to install the I386 or the AMD64 version, but, now, I am curious about this system, also)

--
Bret Busby
Armadale
West Australia
..............

"So once you do know what the question actually is,
 you'll know what the answer means."
- Deep Thought,
  Chapter 28 of Book 1 of
  "The Hitchhiker's Guide to the Galaxy:
  A Trilogy In Four Parts",
  written by Douglas Adams,
  published by Pan Books, 1992

....................................................


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