<Li> Many academic research projects release their results as FOSS . </Li> <P> An analysis of the code of the FreeBSD, Linux, Solaris, and Windows operating system kernels looked for differences between code developed using open - source properties (the first two kernels) and proprietary code (the other two kernels). The study collected metrics in the areas of file organization, code structure, code style, the use of the C preprocessor, and data organization . The aggregate results indicate that across various areas and many different metrics, four systems developed using open - and closed - source development processes score comparably . The study mentioned above is refuted by a study conducted by Coverity, Inc finding open source code to be of better quality . </P> <P> A study was done on seventeen open - source and closed - source software showed that the number of vulnerabilities existing in a piece of software is not affected by the source availability model that it uses . The study used a very simple metrics of comparing the number of vulnerabilities between the open - source and closed - source software . Another study was also done by a group of professors in Northern Kentucky University on fourteen open - source web applications written in PHP . The study measured the vulnerability density in the web applications and shown that some of them had increased vulnerability density, but some of them also had decreased vulnerability density . </P> <P> In its 2008 Annual Report, Microsoft stated that FOSS business models challenge its license - based software model and that the firms who use these business models do not bear the cost for their software development . The company also stated in the report: </P>

Comparison between open source and closed source software