Some members of the open-source community are claiming that the SCO Group may have violated the terms of the GNU GPL (General Public License) by incorporating source code from the Linux kernel into the Linux Kernel Personality feature found in SCO Unix without giving the changes back to the community or displaying copyright notices attributing the code to Linux.
A source close to SCO, who spoke on condition of anonymity, told eWEEK that parts of the Linux kernel code were copied into the Unix System V source tree by former or current SCO employees.
That could violate the conditions of the GNU GPL, which states that any amendments to open-source code used in a commercial product must be given back to the community and a copyright notice must be displayed attributable to Linux, he said.
The source, who has seen both the Unix System V source code and the Linux source code and who assisted with a SCO project to bring the two kernels closer together, said that SCO "basically re-implemented the Linux kernel with functions available in the Unix kernel to build what is now known as the Linux Kernel Personality (LKP) in SCO Unix."
The LKP is a feature that allows users to run standard Linux applications along with standard Unix applications on a single system using the UnixWare kernel.
"During that project we often came across sections of code that looked very similar, in fact we wondered why even variable names were identical. It looked very much like both codes had the same origin, but that was good as the implementation of 95 percent of all Linux system calls on the Unix kernel turned out to be literally one-liners," the source said.
Only a handful of system calls—socketcall, ipc and clone—were fairly difficult to implement as they involved the obvious differentiators between Linux and Unix: networking, inter-process communication and kernel threads, the source said.