How to Set up Dual Boot w/ 2 Hard Disks

[Michele]

I've asked this question before and got answers
on how to set up a dual boot system with
two partitions....only problem is, I don't have
two partitions I have two separate hard drives,
one with Mandrake 8.1, one with Windows ME.

For now, I've been disconnecting one drive,
and connecting the other when I want to switch
the OS.

Can someone please tell me what I need to do
to set these drives up to be able to use both?
I'd love to use Linux more often, but opening
the case gets to be a pain in the ass after awhile.

thanks for your help

[mjt]

Michele wrote:

i was conVINCED this was a troll, but after a quick check out
on groups.google, you seem legitimate :)) i've never known
anyone desperate enough to swap cables to dual-boot!

why not use LILO as the boot manager - it can be a micros~1 OS
and Linux - turn your machine on and choose what you want to
run ...

http://www.tldp.org/HOWTO/mini/Multiboot-with-LILO.html

http://www.tldp.org/HOWTO/HOWTO-INDEX/os.html#OSBOOT
http://www.tldp.org/HOWTO/mini/LILO.html

http://www.tldp.org/HOWTO/mini/Install-Strategies/index.html
http://www.tldp.org/HOWTO/Linux+Windows-HOWTO/index.html#Overview
http://www.linuxselfhelp.com/HOWTO/Bootdisk-HOWTO/

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Michael J. Tobler: motorcyclist, surfer, # Black holes result
skydiver, and author: "Inside Linux", # when God divides the
"C++ HowTo", "C++ Unleashed" # universe by zero

[Jim Ballard]

Modify your /etc/fstab file to include info for Windows partition. Here's
a copy of mine:

/dev/hda6 / ext2 defaults 1 1
/dev/hda5 /boot ext2 defaults 1 2
/dev/cdrom /media/cdrom auto ro,noauto,user,exec 0 0
devpts /dev/pts devpts defaults 0 0
/dev/fd0 /media/floppy auto noauto,user,sync 0 0
proc /proc proc defaults 0 0
usbdevfs /proc/bus/usb usbdevfs defaults,noauto 0 0
/dev/hda1 /win vfat auto,user 0 2
/dev/hda7 swap swap pri=42 0 0

My Windows partition is mapped to /dev/hda1. I have created a writeable
directory '/win' to mount the disk. Hope this helps.

[Clive Dove]

Michele wrote:

It is quite similar to dual boot on a single drive.
Assume that Windows is in the first partition of the first drive and
that linux is in the first partition of the second drive

Then

In /etc/lilo.conf
In the global section:

boot=/dev/hda
default=linux

In the stanzas:

The linux stanza will look something like this:

image=/boot/vmlinuz
label=linux
root=/dev/hdb1
initrd=/boot/initrd.img
append="devfs=mount hdc=ide-scsi"
vga=788
read-only

other=/dev/hda1
label=windows
table=/dev/hda

Don't forget to run /sbin/lilo after you have saved the file.

If, on the other hand, linux is in the first drive and windows is in
the second drive (not really a good idea)
Assuming that they are still in the first partition of each drive:

Then you will have to change /dev/hda1 to read /dev/hdb1
and change /dev/hdb1 to /dev/hda1

So the linux stanza will look like this:

image=/boot/vmlinuz
label=linux
root=/dev/hda1
initrd=/boot/initrd.img
append="devfs=mount hdc=ide-scsi"
vga=788
read-only

But windows doesn't like to be anywhere except in a primary partition
in the first drive, so you have to remap the drives for windows (not
for linux, it can reside anywhere)

Then the windows stanza would look something like this:

other=/dev/hdb1
label=windows
table=/dev/hda
map-drive = 0x80
to = 0x81
map-drive = 0x81
to = 0x80

Caution: Mandrake's installer sometimes incorrectly remaps the drive
even if windows is in the proper position in the first physical drive.
Remapping is only needed if windows is in the second (slave) drive and
not in the first (master) drive

[Bob Robillard]

Michele wrote:
> I've asked this question before and got answers
> on how to set up a dual boot system with
> two partitions....only problem is, I don't have
> two partitions I have two separate hard drives,

I've just recently setup a machine to do that, and
I had the same question. It turns out that two drives
is handled exactly like two partitions on the same drive,
except the device names are different. Like, instead
of /dev/hda1 and /dev/hda2 (2 partitions on one drive),
they are something like /dev/hda1 and /dev/hdb1 (2
partitions on two different drives.)

So, you can follow all the instructions for two
partitions on the same drive, but just change the
partition names to reflect your second drive.

(The one catch I can think of--it you want the
second drive to be the drive that booting happens
on, you need to mess with your BIOS to do that.)

> one with Mandrake 8.1, one with Windows ME.

I did this with NT on the first drive and RedHat
on the second, but it should be similar.

Duke

[Michele]

hi mjt

The reason I swap cables is, I am not
that well versed in Linux yet. I have
installed it and know how to get around,
and am writing this from Linux now,
but I have found most of the how to's
regarding Linux to be pretty confusing
to a newbie.

For example, some of the how to's might
explain that you need to edit the file
/etc/lilo.conf ok this is fine, but
a newbie wouldn't know what to use to open
and edit the file, or where to add the
necessary lines and they don't go as far to explain all that..
I'd like to learn how to do more with this OS if I could find some
help stuff that is written a little better.
Thanks for the links, I'll sift through them
and see if I can get these two drives to work
in the machine together. :-)

[Rob Warren]

When you get a moment, do some reading on the "vi" text editor.

http://www.thomer.com/vi/vi.html

===================================================================
Rob Warren AIM: Greslin2
UNIX Administrator (SCSA, SCNA) Email: r...@greslin.org
Tampa, Florida http://www.greslin.org
===================================================================

[Clive Dove]

Michele wrote:

Try this.

Do this while running linux on your hard drive with the cables switched
as you have described to put the linux disk in the primary master
position.

Make a two boots disk (the normal one, not the install boot disk)
Do this by opening the Mandrake Control Center (the icon is the one on
the KDE desktop that looks like the face of a monitor with a wrench in
the screen and a star over the upper right corner) then Select Boot
then Boot Disk.
The device field should show /dev/fd0 and the kernel field should show
the kernel version for your distro.
Put a formatted disk into the floppy drive then click on "build the
disk"
If you already have a boot floppy, make an extra one.
Label one disk "original boot disk" and the other one "edited boot disk"
(This is so you can later tell them apart as we are going to edit one
of them)

Now mount the disk marked "edited boot disk" and open kedit from a root
prompt to edit the file "syslinux.cfg" thus:

# kedit /mnt/floppy/syslinux.cfg.

Assuming that you have the linux root installed in the first primary
partition, the contents of the file should look something like this

fault linux
prompt 1
display boot.msg
timeout 100
label linux
kernel vmlinuz
append initrd=initrd.img root=/dev/hda1 devfs=mount

If the append line is not exactly the same as above, don't worry about
it as we are only going to make one small change.

Change root=/dev/hda1 to read root=/dev/hdb1

If the number is different than 1, it simply means that your root is in
a different partition so leave the number as you find it.

Now save the file and unmount the floppy and shut down linux.

Open your case and set up the windows drive as primary master and the
linux drive as as slave.

Reboot using the edited boot disk.

If this works, make a copy of the contents of /etc/lilo.conf and post
them so that we can help you to edit the file to set up a multi-boot
using lilo in the mbr.

[Clive Dove]

Clive Dove wrote:

I should have added to the above that when I tried it, I took a
Mandrake 8.1 boot disk that had been used on a system where linux was
in hdb1 and changed hdb1 to dha6 and used it to start a machine with
Mandrake 8.2 in hda6.
It worked, but it threw some error messages while installing some of
the services. I was expecting errors as the machines have different
architectures and are running different kernels in the hard drives.
However, it did give me a desktop and I was able to open /etc/lilo.conf
and edit it.

[Clive Dove]

Clive Dove wrote:

On reflection, I now doubt that this idea will work. The reason is
that I had not taken fstab into account and the fstab file will still
be pointing to hda even though the physical disk is now in the slave
position. The partitions will have become hdb partitions but fstab
will treat them as hda partitions.

So, my great idea is really a dumb one.

mea culpa.

[Bob Robillard]

Michele wrote:

> For now, I've been disconnecting one drive,
> and connecting the other when I want to switch
> the OS.

BTW, if you'd like to keep doing that, here's
a cheap, 3-way IDE switch that fits in a 5 1/4"
drive bay:

http://www.romtecusa.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=Trios&Product_Code=RX-910T6

You can plug 3 IDE drives into it, and select
which one is connected to your IDE channel when
you power up. It's easier than messing with
partitions and bootloaders.

I have one, and it does exactly what it claims.
Looks cool, too, once I painted the beige faceplate
black. :-)

Duke