Any check of MBR, Boot Sector a.s.o. at boot time?

files

The boot sector is loaded by the BIOS. The BIOS does not know about file systems (FAT, NTFS etc). The code in the boot sector is responsible for loading the rest of the bootloader and knows about the file system on the disc. Yes there are checks to prevent the BIOS loading and executing garbage.

Regards Sergio Masci

Not much of a check, though - just looking for two bytes set to a magic value! The BIOS _ALSO_ knows nothing of the MBR structure except for those two blessed bytes that indicate a "bootable" disk.