Booting FreeBSD from the Windows NT Loader
Richard Brooksby
with the FreeBSD boot selector and Windows 95, so I started investigating
other ways to boot. (Has anyone else had problems with Windows 95 and
booteasy, by the way?)
I discovered that the Windows NT loader can be configured to run other
boot sectors from files in the DOS partition. The boot loader's INI file
(usually C:\BOOT.INI) just needs to be edited to point at the file
containing the sector.
DON'T ATTEMPT THIS UNLESS YOU KNOW WHAT YOU'RE DOING. I think you must be
ready to edit partition tables by hand using a sector editor before you
start mucking about with them, in general. I've had to do this on several
occasions to avoid trashing Windows NT, which is a bit sensitive about
them. Make backup copies on floppy disks and make sure you have the
utilities to put them back if things should go wrong.
To boot FreeBSD from the NT loader, copy your existing boot sector for the
FreeBSD partition to a file on the DOS C: drive. Something like this will
do the trick:
dd if=/dev/wd0c of=<path to C>/freebsd.sec bs=512 count=1
(Change wd0c to sd0c if you boot from a SCSI disk. You could copy the
appropriate file from /usr/mdec instead, but I'm typing this from memory
on my Mac and couldn't tell you which ones offhand. Read the manual.)
Then alter the BOOT.INI file on C: so it contains a line like this under
the "[operating systems]" heading:
c:\freebsd.sec="FreeBSD"
The NT boot loader will then give you FreeBSD as an option. You can make
it the default by editing the "DEFAULT=" line in BOOT.INI in the obvious
manner.
You can also add other boot sectors for other systems, although I haven't
tried it with the Linux LILO boot loader. I'd be interested to know if
this works with LILO.
Once you have this working, you can restore the original master boot
record for DOS or Windows 95 use by running "FDISK /MBR" from DOS. You
are less likely to have trouble with Windows 95, Windows NT, or OS/2
booting and partitioning if you keep the default MBR.
I would be interested to hear from anyone else who uses this trick.
Please send me some mail if you try it, successfully or not.
FYI, I'm running:
- FreeBSD 2.0 with a locally patched kernel
- Windows 95 beta (as released on the Microsoft Developer's Network)
- Windows NT 3.51 retail version
--
Richard Brooksby <ric...@harlequin.co.uk>
+44 1223 873881 (voice) +44 1223 872519 (fax)