have i been rooted?

When my RH 7.1 machine boots, it should have only one image option to boot
from at the start-up screen, i.e., "Linux". That is how it has been since I
intalled it several months ago.

But now there are two image options: "Linux" and "Linux bak". What is Linux
bak? I could not find anything in English at google. Has my system been
comprimised or something?