You got it mostly correct Just because one does not multi-boot does not mean no boot-loader is needed. With a single OS, the boot loader does not need to display any menu and can swiftly proceed without even being noticed.

The only thing I'd like to clarify is that by definition no two loaders can take control of the MBR. The Master Boot Record is the one and only first physical 512-byte block at the start of any HD. What is possible - and rather common, is that two boot loaders can be chained. When you copy a lilo boot record from some linux root filesystem to a windows partition and create an entry in boot.ini for that smallish 1-block file, you're chanining lilo to the NT boot loader. When you create an entry for windows in /etc/lilo.conf, you're branching from lilo to the NT bl.

Cheers,

--bald