What is open-source software?

The Wikipedia article on this subject provides useful basic information.

Tools for finding open source software in your code

An article by Sean Michael Kerner at Internetnews.com, "Are You Violating BusyBox's GPL Code?", lists several tools for finding and inventorying open-source software in your own code. (Pactix doesn't sponsor or endorse any of these tools; this information is provided for convenient reference only.)

• Black Duck
• Open Logic
• Palamida

What could you be forced to do if you violate an open-source license?

Suppose your software developers incorporated open-source code into one of your products, and you distributed your product without complying with the open-source license requirement. What might happen if you were to get called on it? It could happen — in 2007, the Software Freedom Law Center (SFLC) filed lawsuits against several companies, including Verizon Communications and Xterasys, for using BusyBox's open-source UNIX utilities without complying with the GPL requirements.

• Can you just rip out the open-source code and pay damages for copyright infringement, without having to make your own code public?
• Or will you be forced to comply with the license requirements — which, if the license is the General Public License, may include having to make your own source code public?

The answer may depend in part on which of the following two approaches a court decides to take:

• The court might hold that, by using open-source code, your developers entered into a contract requiring your company to follow the open-source licensing requirements, including making your own code public if that's one of the requirements; or
• The court might hold that the open-source license is not a contract, but a conditional grant of immunity from suit for copyright infringement, with the immunity being subject to your company's compliance with the license requirements. Because your company did not enter into a contract, it is not obligated to make its source code public. But because your company didn't comply with the open-source license requirements, it did not fulfill the conditions for immunity, and thus it can be sued for infringement.

One federal court seems to be taking the former position: In August 2007, a federal district judge in San Francisco denied an open-source software licensor's motion for a preliminary injunction and dismissed a copyright infringement claim. The defendant was a company that had used the software in its own product. It had not exceeded the scope of the open-source license; it had, however, failed to comply with the license's requirement that the company "duplicate all of the original copyright notices and associated disclaimers." The court's rationale was that the lawsuit was not about copyright infringement, because the company had done no more than what the open-source license permitted; instead, the lawsuit "sounded in" contract law. Jacobsen v. Katzer, No. C 06-01905 JSW (N.D. Cal. Aug. 17, 2007) (White, J., denying motion for preliminary injunction and dismissing copyright-infringement claim).