NT and RedHat Linux on the same disk?

jch's answer here:


keywords: zarchives, Adaptec, SCSI, RedHat 5.0, 7880, Intel R440LX

The sequence I used to get NT and RedHat to exist on the same SCSI disk
using this controller is:
1) Set up a small (e.g. 400M) FAT16 partition at the beginning of the
   disk, using either DOS fdisk or the NT installer.  Install NT into this.
2) Install RedHat on the disk.  Put a small (e.g. 100M) root partition
   just after the FAT16 partition.  It may or may not be important to
   get these both below the 1024 cylinder limit, but I'm not taking
   chances.  Ignore fdisk warnings that the FAT16 partition doesn't end
   on a cylinder boundary.  Ignore the fact that "Begin" fields are
   multiples of 1024, and aren't equal to the "Start" fields.
3) Let LILO play with the first sector of your root partition, *not* the
   master boot record.  Don't let LILO create an entry for NT in the
   boot sequence -- installation will fail with no error message.
4) Reboot into Linux rescue mode using the boot and supplemental
   floppies.  Follow the instructions in the NT OS Loader + Linux
   mini-HOWTO to suck the Linux boot sector off your Linux partition and
   put it onto a floppy (or maybe straight to the FAT16 partition, if
   you're cleverer than me).  Note that because you're using a SCSI
   drive, you can't use "linux single root=/dev/sdaX initrd=" to boot
   straight into Linux (as the mini-HOWTO assumes), but have to go the
   full rescue mode route.  This means you'll have to mount any
   partitions you need (at least /, and /usr too if that's separate)
   manually, and therefore adjust paths to dd and cp appropriately
   (e.g. "dd if=/mnt/dev/fd0...").  You won't be able to use mcopy,
   either, and "copy" in the mini-HOWOTO is a typo for "cp".  For the
   records, I used:
	mount sda2 /mnt
	mount sda8 /mnt/usr
	mount -t msdos /mnt/dev/fd0 /mnt/dev/floppy
	dd if=/mnt/dev/sda2 of=/bootsect.lnx bs=512 count=1
	cp /bootsect.lnx /mnt/dev/floppy
	umount <everything>
5) Reboot into NT.  Use the NT file manager to create NTFS partitions
   in any remaining free space (I used half of the space at the end of
   the disk for NTFS).  Follow the rest of the instructions in the
   mini-HOWTO to put an entry in C:\boot.ini to refer to
   C:\bootsec.lnx.  
6) Reboot.  Gentlemen, choose your operating systems!

Note: I'm keeping the 400MB NT partition as FAT16 so that both NT and
Linux can manipulate C:\boot.ini to pick a default operating system for
the next reboot.

Addendum: don't start a linux partition on the partial cylinder at the
end of the FAT16 cylinder -- use the next one instead.  And although you
can ignore the Begin != Start messages, you might find it necessary to
add the partitions strictly sequentially, as they are laid out on the disk.

yes, an alternative is just to throw two smaller disks in there

yes, this is all because Adaptec support on the RedHat 5.0 boot disks is
suboptimal



 - 24 Feb 1997