Dual boot WinXP & FreeBSD on 2nd HD with boot.ini

Dave Bodenstab

Maybe there are more simple ways to do this, but I did not see the
need to install an additional boot manager. For what it's worth,
here it is... maybe this will save someone else some time.

I saw references for dual booting FreeBSD using WinXP's boot.ini,
but only when FreeBSD was located on another partition of the first
hard drive. In my case, the PC came with WinXP pre-installed. I
then added a second hard drive and installed FreeBSD from the CD.
I did not muck with the master boot block on the first hard drive.

My layout:
Hard drives:
disk 0 (ad0) - Win XP
disk 1 (ad1s1) - FreeBSD
installed via CDROM
mbr option was "none"

I can now boot FreeBSD on the second hard drive using WinXP's boot.ini.
Here is how I solved the problem:

Step 1:

Install FreeBSD on the second hard drive. I put FreeBSD on the first
partition, disk2s1a.

Boot FreeBSD from the second hard drive using the installation CD.
a) Boot the CD
b) Choose 6 (Escape to loader prompt)
c) Type:
set currdev=disk2s1a
boot

Step 2, from FreeBSD, as root:

Create a mbr for the first drive, however it is *not* actually written to
the first hard drive. It is written to the second hard drive from where
it will be copied for use by WinXP's boot.ini.

a) Create a mbr for the first hard drive:

# boot0cfg -Bv -d 0x80 -s 5 -o setdrv,noupdate -t 1 /dev/ad1

This creates a mbr with a default of F5 (boot from second
drive) and a timeout of 1 tick. This mbr is written to the
*second* hard drive (ad1). It will not matter that the partition
table is for the second hard drive since it switches to the
second hard drive immediately.

b) Copy this mbr to a file:

# dd if=/dev/ad1 of=FreeBSD.boot count=1

c) Write the correct mbr to the second hard drive. This mbr will boot
FreeBSD.

# boot0cfg -Bv -d 0x81 -s 1 -o setdrv,noupdate -t 1 /dev/ad1

This creates a mbr with a default of F1 (boot from the first
partition) and a timeout of 1 tick. If you have other bootable
partitions on the second hard drive, you will probably want to
omit the '-t 1' option. Since this mbr *is* actually written
to the second hard drive, it will be loaded by the mbr created
in step a) above. This mbr will then boot from the first
partition of the second hard drive, /dev/ad1s1a.

d) Copy the file "FreeBSD.boot" somewhere from which you can access
it after booting WinXP. I used a floppy:

# mount -t msdos /dev/fd0 /mnt
# cp FreeBSD.boot /mnt
# umount /mnt

I was not able to just copy the file to WinXP's ntfs file system.
I got an error, and I did not pursue this approach since a floppy
works.

Step 3:

a) Remove all media and boot WinXP.
b) Copy the "FreeBSD.boot" file from step 2d) to C:\FreeBSD.boot
c) Use notepad (or any text editor) to edit C:\boot.ini
and add the following line:

C:\FreeBSD.boot="FreeBSD 6.2"


Conclusion:

When you boot, you will now see an option for "FreeBSD 6.2" from WinXP's
boot screen.

When you select "FreeBSD", the mbr that was created in step 2a) is loaded
and run. After a timeout of 1 tick, it uses the default F5 (boot from
second drive), and loads the mbr created in step 2c). This mbr then uses
the default F1 and boots FreeBSD from the first partition.

Dave Bodenstab

Steve Adam

Dave Bodenstab wrote:
> Maybe there are more simple ways to do this, but I did not see the
> need to install an additional boot manager. For what it's worth,
> here it is... maybe this will save someone else some time.
[...]

Thanks for that, Dave. I've been considering installing
FreeBSD instead of Slackware on one of my drives, but
I've hesitated because of uncertainty over dual boot.

I'll certainly be giving this a try.

Steve.

Steve Adam

Steve Adam wrote:
> Dave Bodenstab wrote:
>> Maybe there are more simple ways to do this, but I did not see the
>> need to install an additional boot manager. For what it's worth,
>> here it is... maybe this will save someone else some time.
> [...]
> I'll certainly be giving this a try.

Yep.. It works for me too on NT4.

Steve.

Jason Bourne

Dave Bodenstab wrote:

> Maybe there are more simple ways to do this, but I did not see the
> need to install an additional boot manager. For what it's worth,
> here it is... maybe this will save someone else some time.
>
> I saw references for dual booting FreeBSD using WinXP's boot.ini,
> but only when FreeBSD was located on another partition of the first
> hard drive. In my case, the PC came with WinXP pre-installed. I
> then added a second hard drive and installed FreeBSD from the CD.
> I did not muck with the master boot block on the first hard drive.
[snip]

There is a section that covers this in the FAQ. However, while the
directions for windows/freebsd on the same (1) drive are very easy (done it
myself), the directions for when they are on different drives is a tad
confusing.

These directions, more or less, do the same thing but the step by step is
much more concise and clear. Easy to understand and follow. I really like
things simple, as I'm kinda simple myself. :-)

-Jason

Bnad

Thanks so much Dave--this solved a problem I've had for months. The FreeBSD FAQ just assumes you'll use the FreeBSD boot manager if you have a second drive--which amounts to saying you can't use NTLDR to boot FreeBSD off a second drive. (Or can use NTLDR, but still have to go through two boot menus every time you start FreeBSD--the NTLDR menu and the FreeBSD menu--which could become annoying.)

If these instructions were put in Chapter 9 section 10 of the FAQ, it could help rank beginners like me. Though doing this manually was a net positive for me as I learned more about how MBRs work, I lost my taste for novice exploration after hosing my MBR once and having to use TestDisk to recover my XP partition. These instructions were exactly what I was looking for and now that I've figured out exactly what they're doing, I feel ready to explore further. A little detailed guidance is a good thing!

These instructions worked fine for me--I just had to change ad1 to ar1 since I have RAID partitions, and instead of a floppy I used the FFS file system driver for Windows to access /dev/ar1 directly from XP and copy FreeBSD.boot to C:\. I now have a dual boot XP/FreeBSD 7.0 system that presents only one boot selection menu--the NTLDR menu--at startup.