[Peeweelinux] system initialization

[Ricardo Trindade]

when the module is read automatically you no longer will have to run
ifconfig

-----Original Message-----
From: peeweelinux-admin@adis.on.ca
[mailto:peeweelinux-admin@adis.on.ca]On Behalf Of Barry Gershenfeld
Sent: quinta-feira, 22 de Agosto de 2002 18:35
To: peeweelinux@adis.on.ca
Subject: [Peeweelinux] system initialization


My target system initially needed to be started by hand.  I have
worked it out to the point where it's automatic now.  But there
is a lot of detail down there in those init scripts!  Here's
what I started with:

  - network card module present but I had to load it with "modprobe"
  - modprobe fails because no modules.dep
  - modules.dep is created by "depmod"
  - have to run "depmod"
  - have to run ifconfig to bring up network card

Once the network is up the web server answers requests and all
is well.  Here is what I worked out to solve the above issues:

One premise I worked with was that the system really does know
how to to all this, and I just had something wrong.

I had already learned from adventure with thttpd and net-pf-10
about depmod and modprobe, so I created a task in rcS.d called
00depmod that would run first.  That was temporary and I moved
the depmod to another file later.

The issue with ifconfig led me through the 10Network script,
wherein I found that it will find the ifcfg-eth0 file in
/etc/config and use the contents of that to construct an
appropriate ifconfig...up command.   The assumption that
this would work by itself proved to be correct after I
fixed the driver issue.   However, at this time I discovered
the place to put the IP address (or to set dhcp if I wish
to try that).

The driver modules was a little more interesting.  Looking
through the target scripts I find that there could be
an /etc/rc.modules, which, if present, will read a file
/etc/modules and use that as a list of modules to
be loaded.   This pair of files was not present in my
target system, nor was it present on my host RedHat system;
but they were present on my Coyote (LRP) system.  So,
without any more clues, I decided to write my own rc.modules
file which runs depmod, then loads the modules for the
network card.  That way I have kept the customizations to a
minimum.

I know that insmod will load modules without the help of
modules.dep   The issue of depmod was somewhat of an experimental
investigation (I figured I should know about it).  One thing
that seems to be likely is that depmod can be run on the
kernel libraries after they are compiled, and possibly the
resulting modules.dep can be copied to the target system and
then no depmod is required.

The last issue is that I put "alias eth0 ne2k-pci" into modules.conf
but I was unable to discover who reads that information.  That would
be the other way these modules get loaded (and seems to be the way
it's done in our real linux boxes.)

So the questions are:
  - what runs depmod during startup?
  - do embedded systems usually have a prebuilt modules.dep?
  - what uses modules.conf to find out what modules to load?

Barry

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