the GPL'd components.\footnote{However, these programs do often combine

  with LGPL'd libraries. This is discussed in detail in \S~\ref{lgpl}.}

In the latter case, where the work is unquestionably a separate work of

creative expression, no copyleft provisions are invoked.

Admittedly, a tiny

minority of situations which lie outside these two categories, and thus

do involve close questions about derivative and combined works.  Those

situations admittedly do require a highly

fact-dependent analysis and cannot be addressed in a general-purpose

document, anyway.

\medskip

Most companies accused of violations lack a basic understanding

of how to comply even in the former straightforward scenario.  This document

provides those companies with the fundamental and generally applicable prerequisite knowledge.

For answers to rarer and more complicated legal questions, such as whether

your software is a derivative or combined work of some copylefted software, consult

with an attorney.\footnote{If you would like more information on the

  application of derivative works doctrine to software, a detailed legal

  discussion is presented in our colleague Dan Ravicher's article,

  \textit{Software Derivative Work: A Circuit Dependent Determination} and in

  \tutorialpartsplit{\texit{Detailed Analysis of the GNU GPL and Related

      Licenses}'s Section on derivative works}{\S~\ref{derivative-works} of

    this tutorial}.}

This discussion thus assumes that you have already identified the

``work'' covered by the license, and that any components not under the GPL

(e.g., applications written entirely by your developers that merely happen

to run on a Linux-based operating system) distributed in conjunction with

those works are separate works within the meaning of copyright law and the GPL\@.  In

such a case, the GPL requires you to provide complete corresponding

source (CCS)\footnote{For more on CCS,  see

\tutorialpartsplit{\texit{Detailed Analysis of the GNU GPL and Related

      Licenses}'s Section on GPLv2~\S2 and GPLv3~\S1.}{\S~\ref{GPLv2s2} and \S~\ref{GPLv3s1} of

    this tutorial}.

for the GPL'd components and your modifications thereto, but not

for independent proprietary applications.  The procedures described in

this document address this typical scenario.

\section{Monitor Software Acquisition}

Software engineers deserve the freedom to innovate and import useful

software components to improve products.  However, along with that

freedom should come rules and reporting procedures to make sure that you

are aware of what software that you include with your product.

failure in the software acquisition and procurement process.  Integration

of third-party proprietary software typically requires a formal

arrangement and management/legal oversight before the developers

does not mean the oversight is any less necessary.  Just as your legal

and/or management team negotiates terms for inclusion of any proprietary

product.

Simple, engineering-oriented rules help provide a stable foundation for

free software integration.  Ask your software developers to send an email to a

standard place describing each new Free Software component they add to the system,

and have them include a brief description of how they will incorporate it

into the product.  Make sure they use a revision control system, and have

store the upstream versions of all software in a ``vendor branch'' or

similar mechanism, whereby they can easily track and find the main version

of the software and local changes made.

Such procedures are best instituted at your project's launch.  Once a

chaotic and poorly-sourced development process has begun, the challenges

of determining and cataloging the presence of GPL'd components is

difficult.  If you are in that situation, we recommend the

\href{http://fossology.org/}{Fossology system}, which analyzes a

source-code base and produces a list of Free Software licenses that may apply to

the code.  Fossology can help you build a catalog of the sources you have

already used to build your product.  You can then expand that into a more

structured inventory and process.

\section{Track Your Changes and Releases}

As we will explain in further detail below, the most important component

to maintaining GPL compliance is inclusion of the complete and

corresponding source code in any distributions that you make of GPL'd

software.  Knowing at all times what sources generated a given binary

distribution is paramount.

In an unfortunately large number of our enforcement cases, the violating

company's engineering team had difficulty reconstructing the precise

sources for a given binary distributed by the company.  Ensure that your

developers are using revision control systems properly.  Have them mark or

tag the full source tree corresponding to builds distributed to customers.

Finally, check that your developers store all parts of the software

development in the revision control system, including {\sc readme}s, build

scripts, engineers' notes, and documentation.  Your developers will also

benefit from a system that tracks the precise version of source that

corresponds to any deployed binary.

\section{Avoid the ``Build Guru''}

Too many software projects rely on only one or a very few team members who

know how to build and assemble the final released product.  Such knowledge

centralization not only creates engineering redundancy issues, but it also

endangers GPL compliance, which requires you to provide build scripts.

Avoid relying on a ``build guru'', a single developer who is the only one