Port-i386 archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: i386 boot1.c peculiarity while studying code


one minor nit:

> mbr.S ends up in sector 0 of the disk, it is loaded by the bios.
> pbr.S ends up in the first sector of the mbr partition and is all
>   that the mbr.S (or equiv) loads.
> Both the above get loaded to the same address IIRC 0x7c00, so the
>   pbr code had to relocats itself somewhere else.

Thr _mbr_ code had to relocate itself in order to make room for the
pbr code.

Just for the record: for floppy disks, there is no mbr/partition
table, but sector 0 of the disk holds the pbr code which is then
read by the bios (The reason why the pbr is loaded at the
same address as the mbr code is so you could use the same code for
both floppy and hard disk.)

And while I'm here: the address is correct.

Wolfgang%Solfrank.net@localhost				Wolfgang Solfrank

Home | Main Index | Thread Index | Old Index