Re: Dual boot: FBSD-Vista & FDISK problem

Mark Vasles <nospam@xxxxxxxxxx> wrote:
Bill Laird wrote:

Ok, but this seems like what I did:
1) Vista is installed, I have a ad0S1 reserved to Toshiba, a ad0S2 for C:\
ad0S3 for D:\ and 50Gb left for FreeBSD on ad0S4
2) I boot from the FreeBSD disk, I use Fdisk to select the slice4, allocate
the 50Gb to freeBSD, I make few partition inside the slice, select the
FreeBSD boot manager (option 1), complete the installation with success...
I reboot...

I see :
F1 = (empty)
F2 = windows
F3 = windows
F4 = FreeBSD

The MBR seems lost... the slice 1 and 3 should not be there... and hiting F2
(C:\ slice I guess) doesn't work... impossible to boot in windows!

So if i understand, 1 is the recovery partition, of course should be
here, 2 is the normal Windows partition, 3 is an other non bootable
partition, and 4 is FreeBSD. So hitting F2 should boot Windows, except
that the MBR is incorrect. You should boot a windows cdrom, go to the
recovery console and run fixmbr. A possible solution is try to enter
the BIOS and check if you can set your disk in LBA mode. In LBA mode,
the c/h/s are irrelevant.


I have no idea if windows is still there but iunreachable with MBR broken or
if the Chuncks warning has broken the windows partitions.

No at most the boot loader in the Windows partition doesn't understand
the geometry, if i remember there is a fixboot command to repair the
Windows boot blocks. Don't forget there are several stages for booting:

- the MBR: transfers control to boot blocks on one of the 4 partitions.
Traditionnally used c/h/s to access them, but can use "linear mode" or
LBA or "packet mode", that is "number of blocks" since ages. In FreeBSD
you can tune the MBR by using boot0cfg -o packet to do that. You can
also hide partitions using -m "mask". For Windows it is fixmbr.
- the boot block, which is a small program at the
beginning of the partition which transfers control to a more capable
one. This one used c/h/s on old versions of Windows, but uses linear
mode since at least WinXP. It always uses linear mode in FreeBSD.
- the more capable one is ntloader for WindowsXP and /boot/loader in
FreeBSD. They can do all the tasks without any c/h/s restrictions. The
Windows one has a menu to boot several OS, you can boot FreeBSD with it.

So possible geometry problems are localized to the MBR or first stage
boot loaders.


Thank you for you input!
--
Mark



--

Michel TALON

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