BIOS boot specifications

[Gurganus, Brant L]

I have been on a quest for quite some time to find documentation that tells what the magic locations are for booting a BIOS-based PC. I know there are magic locations on the hard drive that get loaded into memory and while I can find places in the Grub source code where those numbers appear to be used, I have not been able to find any kind of BIOS specification or anything that indicates those numbers. Does such a document exist or are current boot loaders just using the same magic numbers that predecessors have used?

Brant Gurganus
http://www.rose-hulman.edu/~gurganbl