Free software, also known as Open-Source, is a new player in the software world. Though it is mostly popularized by the Linux operating system, it is not limited to it. More and more software applications, tools and libraries are available as free software, for free as well as proprietary platforms. In the COTS business, this raises a host of issues regarding both COTS producers and COTS users, issues that can be technical, economic or legal. From the point of view of producers, it is important to understand where the competition between free and proprietary production of COTS is heading, and what are the natural techno-economic niches for both. From the point of view of COTS-based development, one has to understand issues such as (this list is not limited in any way):legal constraints implied by the different types of licences,
legal liabilities for the software (regarding reliability and fitness, or intellectual property violations),
long-term availability and adaptability,
interoperability and adherence to standard,
technical quality and performances,
implied costs (maintenance, licenses, ... )