\item {\bf FSF enforcement often avoids redundant enforcement cases from

  many parties.}  Most Free Software systems have hundreds of copyright

  holders. Some have thousands. FSF is in a unique position as one of

  the largest single copyright holders on GPL'd software and as a

  respected umpire in the community, neutrally enforcing the rules of the

  GPL road. FSF works hard in the community to convince copyright

  holders that consolidating GPL claims through FSF is better for them,

  and more likely to yield positive compliance results.

  A few copyright holders engage in the ``proprietary relicensing''

  business, so they use GPL enforcement as a sales channel for that

  business. FSF, as a community-oriented, not-for-profit organization,

  seeks only to preserve the freedom of Free Software in its enforcement

  efforts. As it turns out, most of the community of copyright holders

  of Free Software want the same thing. Share and share alike is a

  simple rule to follow, and following that rule to FSF's satisfaction

  usually means you are following it to the satisfaction of the entire

  Free Software community.

\end{enumerate}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% FIXME: expand title, etc.

\chapter{ThinkPengiun Wireless Router: A study in Excellent CCS}

% FIXME

This case study does a step-by-step build and installation analysis of  one

of the best Complete, Corresponding Source (CCS) releases we've seen.  The

CSS release studied here was provided for the binary distribution of a

physical product by ThinkPengiun.  The product is the model

``TPE-NWIFIROUTER'', a wireless router.

The method of

distribution (complete source accompanying the product) and the way the source

was laid out provide very good examples of how to make things easier for both

the distributor and the purchaser of the hardware containing GPLed components.

\section{Root Filesystem and Kernel Compilation}

* We found a CD included in the box that the ThinkPenguin TPE-NWIFIROUTER

  shipped in, labelled "libreCMC v1.2.1 source code".  On the CD, there was a

  README file at the top level, which mentioned that to build the software, one

  needed a GNU/Linux system as well as a list of approximately 10 packages.

  These sorts of plain text instructions are helpful because we know what kind

  of system we are expected to use, and what commands we should run on it.  Such

  instructions are not strictly required, as an obviously-named shell script may

  suffice, but they are helpful in clarifying any ambiguities that may arise.

* Since the instructions didn't mention a specific distro to use, we ran the

  build on an amd64 Debian 6 machine we had, after confirming the packages were

  installed.  In particular, we ran "make", as described in the instructions in

  the README.  The instructions said that "make menuconfig" could be used to

  adjust the settings, but it appeared this step was optional ("Please note that

  the default configuration is what was used to build the firmware image for

  your router. It is advised that you use this configuration.") so we chose to

  skip straight to the "make" step instead.  This was done after extracting the

  librecmc-v1.2.1.tar.bz2 tarball, which was not explicitly spelled out (this

  should ideally be added to the README), but was implied by the

  "u-boot_reflash" file (in the same directory as the README), which explicitly

  used the other tarball.  The build took about 40 minutes to run on our system.

* It was helpful to know that we could use "make menuconfig" for configuration

  changes, as being able to modify the source is an important part of the GPL's

  requirements.  Adding instructions like these shows that the distributor is

  aware of and interested in promoting the spirit of the GPL, by making it

  easier to modify the source than may be strictly required by the GPL's text.

* The "make" step completed successfully on our system and resulted in several

  files being generated in the bin/ar71xx directory, namely firmware images.

  There appeared to be several filesystem and kernel images, for different

  hardware versions.  It was unclear which one to install on the particular

  device we received or how to install it, both of which should have been

  mentioned in the README.

* The above installation issue is mitigated by the availability of a web UI in

  the product that performs firmware image installation.  It would be best if

  instructions like those at http://librecmc.org/librecmc/wiki?name=Tp+MR3020

  were included in the README, as the user cannot be expected to infer that or

  to find such a link.

\section{U-Boot Compilation}

* As mentioned above, we also found a "u-boot_reflash" file at the top level of

  the included source CD.  We followed the instructions for compiling U-Boot,

  which were fairly straight-forward.  One modification would be to mention that

  "\$U-BOOT_SRC" referred to the extracted source directory, which was implied,

  but should have been explicit.

* Additionally, we noticed that the included toolchain binaries, which were used

  by the U-Boot compilation process by default, did not run on our system.  In

  particular, we received this error:

mips-librecmc-linux-uclibc-gcc.bin: /lib/libc.so.6: version `GLIBC_2.14' not found (required by mips-librecmc-linux-uclibc-gcc.bin)

* We found that by removing toolchain/bin and symlinking the toolchain built for

  the filesystem/kernel above in its place, we were able to complete the U-Boot

  build.  Specifically, we symlinked toolchain/bin to:

  ../../staging_dir/toolchain-mips_34kc_gcc-4.6-linaro_uClibc-0.9.33.2/bin