How to boot linux kernel without bootloader?

Question

By default to boot image bzImage of a Linux kernel you need to use the bootloader. If you try to boot the image directly it will give the error:

Booting from Hard Disk...
Direct booting from floppy is no longer supported.
Please use a boot loader program instead.
Remove disk and press any key to reboot . . .

In the older versions of Linux it was possible with:

make zImage

Is it possible to boot without a bootloader in the newer versions of the kernel? If so, how?

Answer 1

It's not possible. At least, not with the not-so-old kernels unpatched.

You have these options:

1. use a bootloader.
2. use an old version of linux.
3. hack direct booting (ie a built-in bootloader) into the kernel source so it works more-or-less like floppy booting in the old days.

Answer 2

If you have an EFI based system, starting with Linux kernel 3.3 the firmware can directly load and execute the kernel.