Software patents, especially when they are granted for trivial algorithms that can easily be reinvented by many developers, represent a serious threat to individual open source developers and small organizations, who cannot afford the costs of patent litigation. Ironically, the situation is even more crucial for open source software than for black box proprietary software, since the code is directly accessible by the patent holders.
In many cases, companies and individuals are trying to get exclusive right on certain technologies through patents, and recently more and more patents on fundamental algorithms and procedures have been granted, especially in the United States. We believe that this is a potentially dangerous practice, not only for open source software in particular, but for the software industry and software practitioners in general. The relatively long time span of currently issued patents and the breadth of some of them are specially disturbing. Also, there is insufficient control on the existence of previous work, and many patents are issued on obvious and ill-defined concepts. These patents can be used as broad-fire weapons against competitors, especially the most smaller ones, unable to afford the costly legal expenses needed to demonstrate that a patent is invalid.
Several clear examples of silly patents have been already exposed by the specialized press. For instance, one of the latest cases is a patent on a `novel' method to correct Y2K problems, using an obvious and widely known technique19. Another example is a recently issued patent on an enhancement to the readability of fonts on liquid crystal display, based on sub-pixel addressing. This technique was not only well known and employed widely on the old Apple II computer, which uses a curiously similar system to create on-screen colors, and that enabled to create a double-hires mode using half pixel shifts and single color addressing, but also presented in several papers through the years.
Open source software is especially vulnerable to patent-based attacks, because only a few open source-based companies have the financial power to protect themselves against patent lawsuits. Also, if a patent is issued on a very broad technology or technique it may be impossible to circumvent the patent and create a patent-free alternative.
For a more detailed discussion on how software patents are avoidable,
including many references to relevant papers on software patent
matters, the reader can refer