I wasn't responding to ninkendo, detaro or alxlaz. I was responding precisely to quotemstr's:
The real reason Linux's ABI boundary is the kernel is just that the kernel and glibc are sperate [projects]
...by pointing out the very real issue that even if they were the same project today, they'd still have to maintain compatibility at the system call layer, because that ship has sailed.
To be more precise, then, the Linux kernel is the ABI boundary because during Linux's fluid and formative period, the kernel and libc were separate projects. I agree that it's mostly epoxied in place now, modulo my lkml libsyscall proposal from a while ago.
The real reason Linux's ABI boundary is the kernel is just that the kernel and glibc are sperate [projects]
...by pointing out the very real issue that even if they were the same project today, they'd still have to maintain compatibility at the system call layer, because that ship has sailed.