It is only the kernel that is ELF only, you can still be 100% a.out in
userland if you like. Linus is changing how the kernel is loaded and this
is very much dependant on the binary format, trying to keep the old
a.out kernel is just asking for bugs to leak in.
As the kernel doesn't use dynamic libraries, it shouldn't even have the
performance penalty of ELF (question do you regain the lost register if
you compile elf -static, or is it just unused?).
Jon.
-- Jon. <jon@gte.esi.us.es, http://www.esi.us.es/~jon>