Re: Running pae kernel on non-pae system
On 02/23/2013 02:15 PM, Dom wrote:
> On 23/02/13 18:36, Debian@paulscrap.com wrote:
>
> I think the pae bit will only be used by CPUs that support it, otherwise
> it will be ignored and run normally. Only some "really old" CPUs (like
> some others I do run) won't be supported.
>
See, that's interesting. Everything else I've read says the kernel
won't boot. In fact Ubuntu and derivative users have been experiencing
issues related to that for awhile as they dropped support for non-pae
kernels since 12.04. (I was running Lubuntu 12.10 on this laptop
previously, but the kernel was stuck to what was in Lubuntu 11.10.) On
boot non-pae systems get "This kernel requires the following features
not present on the CPU: pae Unable to boot - please use a kernel
appropriate for your CPU.".
Funnily enough, merely 20 minutes after I posted here, someone posted a
reply on Ubuntu-users to someone else's issue about Lubuntu's 12.10
generic kernel not booting.
The replier says a pae kernel can boot and run fine on a non-pae cpu if
the cpu *reports* it can do pae. There's apparently a tool (fake-pae)
that puts the string "pae" in /proc/cpuinfo.
I know I'm not running fake-pae, yet it still boots, so I'm wondering if
Debian has done something to the kernels to not check the cpu flags? I
note Dom's Pentium M system doesn't have pae in flags either (Though his
Celeron does, which it should anyway.).
> My laptop shows:
>
> model name : Intel(R) Pentium(R) M processor 1600MHz
> flags : fpu vme de pse tsc msr mce cx8 sep mtrr pge mca cmov
> clflush dts acpi mmx fxsr sse sse2 tm pbe up bts est tm2
>
> and an even older laptop gives:
>
> model name : Celeron (Coppermine)
> flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov
> pse36 mmx fxsr sse up
>
> Both running the 3.2.0-4-686-pae kernel
>
--
PaulNM
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