I wrote a more elaborate bootloader for a job about 15 years ago - it was a fun challenge to squeeze a lot of functionality into such a small, limited package.

I wrote a more elaborate bootloader for a job about 15 years ago - it was a fun challenge to squeeze a lot of functionality into such a small, limited package. At the time, bootloaders could add additional functionality by staying resident and hooking various interrupts to provide services or work around bugs in the BIOS. For instance, my bootloader would translate sector mappings that would allow WinPE to boot from USB drives that would not otherwise work due to (idiotic) limitations in some BIOSes. This is a fun example but doesn't really go very far. Handling memory and reading additional code from disk are other topics that are required for a full bootloader, but this was a nice trip down memory lane.