Re: [Hampshire] How to tell how much memory?

On Sat, 14 Jul 2007 19:34:11 +0100
"Victor Churchill" <victorchurchill@???> wrote:

> On 14/07/07, Jonathan Hudson <jh+hlug@???> wrote:
> > On Sat, 14 Jul 2007 18:18:37 +0100
> > "Victor Churchill" <victorchurchill@???> wrote:
> > > But ...
> > > memtest says it is testing 768 MB.
> > > 'top' says 769500 K.
> > > System Monitor 751.5 MB.
> > > /proc/meminfo 769500 .
> > > dmesg : 762904K/786368K total.
> > >
> > > All I can think of is that one of my mem sticks is faulty and thinks
> > > it is 512 MB, and reports this, but in fact has 'lost' half of it
> > > (address line stuck?)
> > >
>
> > You have a kernel build with the (old) <1G memory model. In this mode
> > Linux does only see 768K.
> >
> > You need to build the kernel with 1+3 or 2+2 (mapping of VM between
> > kernel and user space) or whatever its called.
> >
> > I expect the hardware is fine.
> >
> > -jonathan
> >
>
> OK ... but rather surprising. This box is running feisty 7.04, and
> uname -a gives
> 2.6.20-16-generic #2 SMP Thu Jun 7 19:00:28 UTC 2007 x86-64 Gnu/Linux
>
> So not an 'old' kernel ... but maybe the default build uses the 'old'
> memory model.

Bizarre: if it's the Ubuntu 7.04 kernel then it's a 4GB one. I have that
on my legacy 686 box. And if it's a x84-86 box then the ia-32 memory
stuff is not even relevant (didn't previously realise it was 64bit CPU).

Very strange. Kernel is unlikely to be the problem.

-jonathan