“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. We analyze the source code
of the four systems by collecting 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 wildly different processes score comparably. This
allows us to posit that the structure and internal quality
attributes of a working, non-trivial software artifact will
represent first and foremost the engineering requirements of its
construction, with the influence of process being marginal, if
any…”