[Someone]

That "fanatical dedication to backwards compatibility" works even harder towards glacial development for the OS than for applications. Or do you think OS developers will ship a new, faster scheduler, tweak the memory allocator and the thread scheduler every month?

[rbanffy]

Plus, you won't get five nines reliability if you tweak the kernel every week.

Mainframes are built to never stop, to never give you a headache and to never, ever surprise you.