[ELDK] Creating small target rootfs in DENX

Phil Terry pterry at micromemory.com
Wed May 28 17:24:11 CEST 2008

On Tue, 2008-05-27 at 15:57 -0400, Dave Rensberger wrote:
> Phil,
> So if I understand your description below, it's pretty much my
> responsibility to go through the rootfs and figure out which binaries,
> libraries, and configuration files are needed in my target distribution?

Thats how I understand and use it.

> There isn't anything in the ELDK that automates the process of whittling
> this set of files down, right?

Not that I know of... but I'm just a user... no inside knowledge of what
Wolfgang is up to ;-)

It depends on your mindset. Most "embedded, no resources spare" people
would start with SELF which gives you a boot up and busybox plus ftp and
telnet. You throw in your application programs, daemons, utilities plus
any shared libraries they use (if not static). Then maybe you peruse the
full install to see if there are any other goodies that are must have,
and maybe throw those in. (if dynamic use ldd to find shared library
dependencies and throw those in as well). So building up a minimal is
pretty straightforward I think.

Starting the other end and trying to see how much you can remove without
something thats left breaking is somewhat more frustrating, dependency
tracking through shared libraries etc. And most RPM packages are not
that good at declaring dependencies that really matter... admin scripts
for a package being dependent on little utilities from other packages,


> --Dave
> -----Original Message-----
> From: Phil Terry [mailto:pterry at micromemory.com] 
> Sent: Friday, May 23, 2008 3:07 PM
> To: Dave Rensberger
> Cc: pterry at vmetro.com; eldk at lists.denx.de
> Subject: RE: [ELDK] Creating small target rootfs in DENX
> On Fri, 2008-05-23 at 14:48 -0400, Dave Rensberger wrote:
> > OK. I saw that, but the documentation that I read had lead me to
> believe
> > that SELF was nothing more than a collection of small example
> rootfses.
> Well thats what you want right? An example setup of how to create and
> manage a subset installation to a rootfs which is absolutely minimal so
> you can simply add to it.
> You will need to edit the line in spec file which just copies in the
> "dummy" application, a hello world shell script, with something more
> substantial. 
> In the source tree you edit the various *.list files which control the
> subset of your "full install" tree which get copied in.
> In the spec file you could either explicitly copy your application
> executables, libraries and data files instead of the dummy or set up an
> "application.list" mechanism as they use for the other stuff, or simply
> edit the libraries and files list files which are already there to
> include your application.
> When you've done all that you simply rpmbuild a new src and binary rpm
> so that your fellow developers and/or customers simply install your
> version of the SELF rpms
> SELF is an example of a package which you actually have to get in and
> edit using the install of the src rpm, rpmbuild -bp, edit, rpmbuild -ba
> etc.
> Hope this is helping...
> > I'll go back and read about it again.
> > 
> > --Dave
> > 
> > -----Original Message-----
> > From: Phil Terry [mailto:pterry at micromemory.com] 
> > Sent: Friday, May 23, 2008 2:29 PM
> > To: Dave Rensberger
> > Subject: Re: [ELDK] Creating small target rootfs in DENX
> > 
> > On Fri, 2008-05-23 at 13:04 -0400, Dave Rensberger wrote:
> > > This is a multi-part message in MIME format.
> > >  discussed or documented, but I haven't
> > > been able to find any info on this topic.
> > > 
> > >  
> > > 
> > > My question regards how to create the subset of the default root
> file
> > > system generated by the ELDK "install" script that will be the
> rootfs
> > > resident on my target.   
> > 
> > I believe what your looking for is the SELF package in ELDK, install,
> > edit to taste and install.
> > 
> > Simple Embedded Linux Filesystem (SELF)
> > 
> > Its not obvious, I missed for a long time then once I found it and
> > realized what it was I couldn't work out why it wasn't obvious.... :-)
> > 
> > Cheers
> > Phil
> > 
> > 
> > 
> > 
> > 

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