On Sun, 2 Sep 2001, Mark Glassberg wrote:
> I rewrote /etc/lilo.conf--incorrectly as it turned out--and ran lilo.
> Lilo rewrote the boot sector of the msdos partition, not the mbr of the
> drive.
In short: I hope you have backups. :-(
The format of the PBR (Partition Boot Record) is application-specific.
For an MS-DOS filesystem, I believe that would be such details as the DOS
bootstrap code, and the location of the FATs and the root directory.
I assume you can still boot Linux. Do so. Then run
lilo -u
That tells the map installer (/sbin/lilo) to "uninstall" LILO. If you have
modified /etc/lilo.conf since you installed LILO over the DOS PBR (e.g., to
"fix things"), undo your changes. LILO needs the same config file
(specifically, the same boot device (location to install to, -b switch,
boot= parameter)) to uninstall the right thing.
On Mon, 3 Sep 2001, Derek Martin wrote:
> I could be way off here, but I think DOS just stores the io.sys and
> msdos.sys files in the first sector ...
The PBR contains bootstrap code and (I am fairly sure) the "media
descriptor", the FAT equivalent of the filesystem superblock. The bootstrap
code has enough intelligence to read IO.SYS (or IBMBIO.SYS) into memory and
jump to it. IO.SYS is responsible for loading MSDOS.SYS (or IBMDOS.SYS).
Both files are contained outside the PBR. The critical part is the media
descriptor. There are no superblock backups for FAT.
> so you might be able to boot with a DOS (or win9x as appropriate) boot
> floppy, and run
>
> a:\> sys c:
I am pretty sure that will not work, since C: will not exist until the DOS
kernel recognizes it as a filesystem, and it will not recognize it as a
filesystem until the media descriptor (PBR) is repaired.
--
Ben Scott <[EMAIL PROTECTED]>
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