Simplest chainloading a boot manager
问题 In order to boot from flash memory drive we load disks using the BIOS interrupt 13h in real mode with specifying the disk 0x80. Another disks should be accessed by 0x81, 0x82... as mentioned over this link I am trying to make my simple GRUB . My very first step is to boot from flash memory drive (Load MBR into 0x7C00 and print a message as a proof of correct boot) and read the my main HDD (which I assume it is numbered 0x81 and that the first 15 sectors are needed for booting) again into