Kernel Comparison: FreeBSD, GNU/Linux, Solaris and Windows

The perpetual face-off between operating systems certainly goes deeper than the shell, and in this context, a critical aspect of such a comparison is a "measuring contest" involving the core of the platforms. Diomidis Spinellis, from the Department of Management Science and Technology, Athens University of Economics and Business, compared four kernels in a white paper for the "30th International Conference on Software Engineering" (ICSE '08). The whitepaper titled "A Tale of Four Kernels" offers an insight into the kernels of FreeBSD, Linux, OpenSolaris, and the Windows Research Kernel (WRK).

"The Freebsd, gnu/Linux, Solaris, and Windows operating systems have kernels that provide comparable facilities. Interestingly, their code bases share almost no common parts, while their development processes vary dramatically," revealed Spinellis. "(...) The recent open-sourcing of the Solaris kernel and the distribution of large parts of the Windows kernel source code to research institutions has provided us with a window of opportunity to perform a comparative evaluation between the code of open source and proprietary systems."

Spinellis offers an indepth view of the the source code in the operating four systems while focusing on an array of aspects, including file and data organization, both the structure and the style of the actual code, C preprocessor implementation. The conclusion offered by Spinellis is that the kernels of the four platforms manage not to deliver "significant across-the-board code quality differences." Essentially, the scores obtained by FreeBSD, Linux, OpenSolaris, and the Windows Research Kernel are comparable without indicating any superiority either from the open source or the proprietary products.

"Despite various claims regarding the efficacy of particular open or close-source development methods, we can see that there is no clear winner (or loser). The two systems with a commercial pedigree (Solaris and WRK) have slightly more positive than negative marks. However, WRK also has the largest number of negative marks, while Solaris has the second lowest number of positive marks. Therefore, the most we can read from the overall balance of marks is that open source development approaches do not produce software of markedly higher quality than proprietary software development," Spinellis concluded.