Comments on: Linux Find If Processor / CPU is 64 bit / 32 bit ( long mode ~ lm )

By: josh

josh — Wed, 21 Dec 2011 17:21:52 +0000

lshw -class processor

By: josh

josh — Wed, 21 Dec 2011 17:21:07 +0000

simply use the following command
lshw -class processor

By: nicole

nicole — Thu, 08 Dec 2011 14:06:58 +0000

IBM Power 5 510
uname -m
ppc64

getconf LONG_BIT
32
Loaded OS
RHEL 5.6 PPC

why it says 32 bit?

By: Saurabh

Saurabh — Thu, 10 Nov 2011 07:11:40 +0000

uname -m

By: al

al — Tue, 08 Nov 2011 22:29:27 +0000

Big thanks.

By: Jeremy

Jeremy — Mon, 05 Sep 2011 03:54:38 +0000

That’s because you are running a 32bit kernel.

By: Bill

Bill — Tue, 14 Jun 2011 21:02:10 +0000

Thank you Jamieson for the most useful, polite and comprehensive reply. I so wish the internet had more ppl like you and less…

IMO It put a lot of the others to shame who seem to like to chitchat on stuff they don’t really know (yes, this was not polite, on purpose).

/Bill

By: Sniper

Sniper — Thu, 19 May 2011 00:26:53 +0000

@ dhanalakshmi:
From the output of “uname -a” it seems that your OS is most likely a 32 bit Debian (or ArchLinux, or Linux Mint; more probable one of the first two) on 2.6.29.1 custom-built 32-bit SMP kernel running on a 2 GHz laptop computer.

By: dhanalakshmi

dhanalakshmi — Wed, 18 May 2011 10:54:37 +0000

from this command :
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe nx up bts est tm2

from this command :
Linux dhanalakshmi 2.6.29.1-desktop-4mnb #1 SMP Mon Apr 20 18:57:56 EDT 2009 i686 Intel(R) Pentium(R) M processor 2.00GHz GNU/Linux

Can you tell me please
what os is mine ?

By: Shiva

Shiva — Sun, 10 Apr 2011 19:11:24 +0000

you info was very helpful..

By: Niels Dettenbach

Niels Dettenbach — Tue, 22 Mar 2011 12:05:32 +0000

yes,

BUT

cat /proc/cpuinfo

does not give a reliable information about 64bit cap. cpu hardware too as several different CPU types gives different flags here etc. (see the thread). This means you have do dig into the CPU specs from the vendor to be *really* shure (or try to start a 64bit OS).

By: typhoon

typhoon — Tue, 22 Mar 2011 05:08:03 +0000

# getconf LONG_BIT seems only os 32 or 64 bit that running on your pc
it must not be cpu 32 or 64 bit
may need command cat /pro/cpuinfo for more information about cpu

By: Niels Dettenbach

Niels Dettenbach — Thu, 03 Mar 2011 09:19:41 +0000

> -m, –machine
> print the machine hardware name
This is correct – but not your interpretation of it.

If you run i.e. a i386 sys on a 64 bit capable box you can get ‘i386′ but not ‘x86_64′ or something 64bit related. But this all was still topic in this thread here:
http://www.cyberciti.biz/tips/how-do-i-find-out-if-my-server-cpu-can-run-a-64-bit-kernel-version-apps-or-not.html

The only thing you can say if a 64bit system runs on that hardware (and so will print out uname -m implicite) it IS 64bit capable.

And in a very precise way even dmidecode doesn’t gives you are reliable answer as there are incomplete or incorrect dmi implementations out there. So the most / only reliable way is to try boot a 64bit OS.

cheers,

Niels.

By: Manoj

Manoj — Thu, 03 Mar 2011 08:09:50 +0000

Yes you are correct about “getconf LONG_BIT” but manual says:

man uname

-m, –machine
print the machine hardware name

Machine hardware name will be architecture….

Thanks,
Manoj

By: Niels Dettenbach

Niels Dettenbach — Thu, 03 Mar 2011 08:02:35 +0000

No, this is not correct as you can read in the discussions here.

“uname” just gives you out how your sys was compiled – not the hardware specs. If it IS a 64 then you (should) HAVE a 64bit (capable) CPU – but not vice versa!

Just to sum up the discussion here: To find out if a cpu id 32 or 64 bit you have the following options – from less reeliablest to reliable:

– uname
– getconf LONG_BIT / cat /usr/include/asm/cpufeature.h
– cat /proc/cpuinfo
– DMI / dmidecode
– try to boot a 64bit linux (i.e. live system) or read the public specs of a CPU

OK?
This means uname is the option with the lowest (!) trust in this question.

cheers,

Niels.

By: Manoj

Manoj — Wed, 02 Mar 2011 11:37:03 +0000

This can also be achieved by following:

uname -i
or
uname -m

Corrent me if am wrong :)

By: Niels Dettenbach

Niels Dettenbach — Thu, 30 Dec 2010 08:19:25 +0000

afaik lshv uses DMI too – so it does not get more informations out then dmidecode or other described sources here – just brings it into some “nice” (may just overloaded in this scenario) HTML stuff). I assume that is usualy not that what peoples want if they want to script something…

Not at least: as dmidecode and other DMI-tools it works only if the kernel provides DMI access / drivers to the regarding hardware.

As i stated before – there is no reliable (!) way to find out if a CPU (which is not shown as 64bit capable by all these tools and commands) is NOT a 64bit capable one. dmidecode (DMI) is (afaik) the most reliable source on system side but not correct in each case.

In such cases you have to:

– dig after the (original) CPU spec docs
OR
– just try to start a 64bit system (i.e. a Live CD or USB)

cheers,

Niels Dettenbach.
http://dettenbach.de

By: LinuxAdmin

LinuxAdmin — Wed, 29 Dec 2010 22:05:10 +0000

getconf LONG_BIT
which returns either 32 or 64
says nothing about the cpu capabilities, just the os that is running. ( you can run 32bit os on 64bit capable chip, but not the other way arround) the ;
> cat /proc/cpuinfo
and looking for lm seems to tell you if it is capable of 64bit
and it also tells you the chip and model # which you can google and verify.

By: Snowbird

Snowbird — Mon, 27 Dec 2010 22:29:42 +0000

Forget everything and just use in your shell window
lshv

If you dont have this try installing it (yum install lshv)
this utility will give you more than what you want to know :)

you can also get html report of your complete hardware info by typing:

lshv -html > report.html

By: Niels Dettenbach

Niels Dettenbach — Tue, 26 Oct 2010 14:33:35 +0000

please read postings more down – this is not correct in any case too…

cheers,

Niels.
—
http://www.dettenbach.de