Re2: Image modules?

[David Fokkema]

On Sat, 2009-07-04 at 17:52 +0200, Glenn Moeller-Holst wrote:
> At 14:47 +0400 04/07/09, Paul Fertser wrote:
> >Glenn Moeller-Holst <glenn.mh.dk at gmail.com> writes:
> >> 
> >>modules-2.6.28-stable+gitr0+f19f259d3c1afde8eae53983fd19f61831927413-r2-om-gta02.tgz
> >>
> >>  Is it nessecary or advicable to flash it onto the phone?
> >
> >Flashing tar.gz archives makes little sense. You might want to untar
> >it to your / though in case you don't have that modules already.
> >
> >--
> >Be free, use free (http://www.gnu.org/philosophy/free-sw.html) software!
> >mailto:fercerpav at gmail.com
> 
> This is what I am not able to read anywhere:
> *I actually do not know if I already having modules installed? How do
> I test it?

Look in /lib/modules/<kernel-version>, or unpack the modules file and
check. You'll find you already have it.

> *What is modules used for?

Lots of hardware drivers are not needed by all pc's (or phones, for that
matter) or are not needed all the time. To keep the size of the kernel
binary small and to limit memory usage, these drivers are not compiled
into the kernel, but rather as 'modules'. Usually, modules are loaded
into memory if and when needed by the kernel.

For our freerunners, this probably means that things like wifi and
bluetooth are modules, which are not always active and thus not always
loaded in memory. Generally, things like ati video drivers, ide drive
drivers and braille tty drivers are not compiled and included at all,
since that would make no sense.

> *Is modules (already) included the image?

Not in the kernel image, but they are included in the root image.

> *Why is there a separate file called modules? Why not include it in the image?

It _is_ included in the root image, as it lives in the root filesystem
in /lib/modules. The thing is: if you decide to use that kernel but
_not_ use that root filesystem (because you'd like to build your own,
for example, or you just want to upgrade your kernel and _not_ your
filesystem) you'll have to untar the corresponding modules into your own
filesystem.

> *Is modules a standard Linux "thing"?

It is a standard linux feature. But it is certainly not limited to
linux, although naming conventions may vary.

> I am asking as a novice. I have not encountered information about modules at:
> http://wiki.openmoko.org/

Google 'linux kernel modules' and you'll find more than you'll ever want
to know.

HTH,

David