On 2017-03-03 18:04, Alec Destry wrote:
"the two inmutable or unmovable files - sorry, I don't remember the names, and they can vary a bit. The boot record has the position of those two files created at format /s time hard written."
I believe the names of those files are: IO.SYS and MSDOS.SYS and they have to be listed as the first and second files respectively in the root directory.
Yes, those were the typical names. Another variant was something like ibmio.sys, I think. But the position in the root directory was irrelevant: what mattered was the actual blocks in the disk they occupied. The function that reads them into memory at boot knows nothing about reading directories. It just loads blocks of disk data into specified memory location. It is the same function, I believe, that the boot record code uses currently to load grub on MBR disks. They were the first entries in the directory because normally they were created on empty disks. But you could create them much later on a disk that already hold data with the command SYS. -- Cheers / Saludos, Carlos E. R. (from 42.2 x86_64 "Malachite" (Minas Tirith))