Re: Identifying CPU and current OS
At Sun, 28 Sep 2025 07:45:56 -0500 Richard Owlett <rowlett@access.net> wrote:
>
> On 9/28/25 7:23 AM, Robert Heller wrote:
> > At Sun, 28 Sep 2025 07:00:11 -0500 Richard Owlett <rowlett@access.net> wrote:
> >
> >>
> >> I may resurrect an former desktop machine as a trouble shooting aid.
> >> I need to know the data bus width.
> >>
> >> I know the Debian version number is stored in /etc/debian_version .
> >>
> >> How do I find if the installed OS is 32 or 64 bit?
> >> How do I discover the CPU's bus width?
> >
> > uname -a
>
> The output of
> Linux debian12 6.1.0-28-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.119-1
> (2024-11-22) x86_64 GNU/Linux
> Is clear. I *like*!
This is a 64-bit kernel for a x86_64: Intel/AMD processor.
>
> >
> > This will tell you the kernel version, including the bus width
> > (Note: it is possible to install a 32-bit kernel on a 64-bit processor)
>
> That is the case of interest. I'm fairly certain that it has 32 bit
> Debian installed. I need to know if the processor is 64 bit capable.
> >
> > cat /proc/cpuinfo
> >
> > This will tell you all about the processor(s).
>
> But as I replied to alain, I didn't find the data buss width clearly
> identified.
/proc/cpuinfo is not going to bother with that (it does not need to). It can
be infered from the address bus with. If the number of address bits are <= 32
it is 32-bit, otherwise 64 bits. And one can always put the CPU model name
into a search engine. I don't think any x86_64 processors actually provide 64
address lines, even though the processor does have 64-bit registers. Subsets
are used as inputs to the MMU (virtual address bits) and the MMU only has a
subset wired to the processor's pins (physical address bits). A 64-bit
processor has more that 32 of each and a 32-bit processor generally has 32 (or
fewer) (PAE i686's have more than 32-physical bits -- a sort of resurrection
of 8086/80286 segmented memory address games).
But the results of uname is difinitive. A 64-bit kernel won't run on a 32-bit
CPU, although a 32-bit kernel will run on a 64-bit processor. So if the
*kernel* is 64-bit, the processor is 64-bit. It is possible to have both
32-bit and 64-bit user-mode programms installed [on a 64-bit processor with a
64-bit kernel], if all of the proper libraries, including the
/lib/ld-linus-*.so files. (I guess it is possible to install a 64-bit kernel
and all 32-bit user-mode files, but why would one do that?)
>
>
> >
> >
> >
> >>
> >> TIA
> >>
> >>
> >>
> >
>
>
>
--
Robert Heller -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software -- Custom Software Services
http://www.deepsoft.com/ -- Linux Administration Services
heller@deepsoft.com -- Webhosting Services
Reply to: