[ELDK] Creating small target rootfs in DENX

Dave Rensberger David.Rensberger at ambientcorp.com
Wed May 28 20:25:03 CEST 2008

By the way, how was the root fs in the SELF package generated?   Were
the files just hand picked from the larger distribution, or is there
some sort of  process that does it?

It's too bad that there isn't a package with just the minimal set of
library objects that you need for a small distribution.   The
crosstool-targetcomponents-ppc_4xx-0.43-1.ppc.rpm contains the basic
libraries, but it give you way more than that... more than you would
want for a small target.   I'm surprised that this hasn't been
subdivided into smaller packages (is this something that was inherited
from Fedora?).   If there were an RPM that just contained the basic
glibc library, I think you could generate an acceptable target rootfs by
just generating your device files and installing a few RPMs.


-----Original Message-----
From: wd at denx.de [mailto:wd at denx.de] 
Sent: Wednesday, May 28, 2008 11:47 AM
To: pterry at vmetro.com
Cc: Dave Rensberger; eldk at lists.denx.de
Subject: Re: [ELDK] Creating small target rootfs in DENX

In message <1211988251.22150.7.camel at pterry-fc6.micromemory.com> you
> 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
> telnet. You throw in your application programs, daemons, utilities
> any shared libraries they use (if not static). Then maybe you peruse

ACK, that's the best  way  to  go.  To  get  a  well-designed,  small
embedded root file system you should know exactly why you need to add
a specific file to the target root file system.

> Starting the other end and trying to see how much you can remove
> 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
> for a package being dependent on little utilities from other packages,
> etc.

Trying to shrink a full-blown istribution results typically in 10...20
times the size of a file system build bottom up.


Perfection is reached, not when there is no longer anything  to  add,
but when there is no longer anything to take away.

Best regards,

Wolfgang Denk

DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Obviously, a major malfunction has occurred."
              -- Steve Nesbitt, voice of Mission Control, January 28,
                 1986, as the shuttle Challenger exploded within view
                 of the grandstands.

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