Inspired by UEFI, I want to skip the stage of the bootloader (grub, lilo, syslinux) and boot linux directly. Is this possible? Cant I just boot the kernel directly, or have a minimalistic bootloader that fits in the MBR?
The space available in the MBR itself is tiny. (About 400 bytes or something.) That's way too small to fit an entire filesystem driver. Without a filesystem driver, there's no way to figure out where on disk the kernel is stored, and hence you can't load the kernel.
You could try hard-coding the location of the kernel into the MBR itself. But then if the file ever moves on disk (e.g., you defrag the disk), the system stops booting.
EFI apparently includes a FAT driver, meaning you can put a bunch of files on a partition that's formatted with FAT and load executables from there. So you could maybe put the Linux kernel onto that somehow... I don't know enough about EFI to say much about it.
The same question has already been asked. I cannot flag it as a duplicate since the original was on superuser, not on unix. Here's the link: https://superuser.com/questions/415429/how-to-boot-linux-kernel-without-bootloader