And yet two more comments:
1) Slide 20, one row before last:
<suppling
>supplying
2) The ROM BIOS boot loader does *not* look for a boot program on sector 0
of the active partition; this is what the standard master boot program
(e.g. the one written there by MS-DOS fdisk) does. Instead the ROM BIOS
boot loader checks if the hard-disk is bootable by looking whether the
last two bytes of the first sector contain a valid boot sector signature
(0x55AA), and if this is the case, it loads the first sector into memory
at address 07C0:0000 and jumps to that address. The DL register contains
the drive number as per int 0x13 (i.e. 0x80 for the first hard disk,
0x81`for the second hard-disk, and so on).
The first sector of a hard-disk contains the master boot record (MBR)
which consists of the following parts:
boot program -- 416 bytes
partition table 4 entries of 16 bytes each -- 64 bytes
0x55AA signature -- 2 bytes
For non-bootable drives the boot program is not used.
The standard boot program of the MBR (e.g. the one written there by MS-DOS
fdisk) examines the partition table and searches for an active partition,
loads the first sector of the active partition at 07C0:0000 (yes, exactly
at the same address) and passes control to the code there, whith the DL
register contining the name of the drive.
However, on most Linux installations the standard MBR boot program
is replaced by LILO, which is not really a good idea because it makes its
uninstallation process more complicated. LILO can and should be installed
on the active partition and the MBR program should be left unchanged.
Emil
On Fri, 14 Jun 2002, Orr Dunkelman wrote:
> http://vipe.technion.ac.il/~orrd/lecture.ps
>
> Comments, etc. are welcome...
>
> --
> Orr Dunkelman,
> [EMAIL PROTECTED]
>
> Computers make it easy to do a lot of things, but most of the things they
> make it easier to do, don't need to be done. --Andy Rooney
>
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