Ultra-tiny HOWTO: multi-distro config -OR- Stupid LILO tricks

	(copyleft) 1999, 2000 by Brian Coyle	brianc@magicnet.net
    	This document may be freely distributed under the FDL.
	http://www.gnu.org/copyleft/fdl.html


In early 1999, I picked up a 13Gb drive ($150.00 at Office Depot -- big
sale).  I slapped it into an old P90 and created a great platform for my
experimentation with all the different distros.   Here's how I did it -
as always, YMMV.

My test system has a 850Mb /dev/hda and the 13Gb /dev/hdc (the CD is
/dev/hdb).

I carved up hda so I have:

Disk /dev/hda: 32 heads, 63 sectors, 827 cylinders
Units = cylinders of 2016 * 512 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hda1   *         1        50     50368+  83  Linux
/dev/hda2            51       101     51408   83  Linux
/dev/hda3           102       183     82656   82  Linux swap
/dev/hda4           184       823    645120   82  Linux swap

hda1 (WAY oversized) contains lilo config
hda2 holds kernels (/boot/distro_name)
hda3 is Linux swap (I have 40Mb of real memory, thus 80Mb swap)
      this is shared by all Linux distros, Solaris has its own.
hda4 is Solaris x86 - yes, Sun uses a Linux swap ID number <grrr>

I put Solaris x86 on the little drive because it doesn't like big drives
(>1024 cyl).

The big drive is simply carved into large chunks for each distro.

Disk /dev/hdc: 16 heads, 63 sectors, 25228 cylinders
Units = cylinders of 1008 * 512 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hdc1             1      2439   1229224+  83  Linux
/dev/hdc2          2440      4878   1229256   83  Linux
/dev/hdc3          4879      7317   1229256   82  Linux swap
/dev/hdc4          7318     25228   9027144    5  Extended
/dev/hdc5          7318      9756   1229224+  83  Linux
/dev/hdc6          9757     12195   1229224+  83  Linux
/dev/hdc7         12196     14634   1229224+  83  Linux
/dev/hdc8         14635     17073   1229224+  83  Linux
/dev/hdc9         17074     19512   1229224+  83  Linux
/dev/hdc10        19513     21951   1229224+  83  Linux
/dev/hdc11        21952     24390   1229224+  83  Linux
/dev/hdc12        24391     25228    422320+  83  Linux

Since this is just a test system, I didn't get fancy with mount points
everything goes under /.  That little 420Mb hdc12 became a /home mount 
point shared across the distros.

If you decide to share a file system across distro's, be sure all your 
user and group ID's match.  That will ensure the correct permissions 
when booting another OS.

/dev/hda2 holds the kernels in in a /boot/distro_name directory:

[root@testsys /]# ls -l /boot
total 66
drwxrwxr-x   3 root     root         1024 May 27  1999 RH60
drwxr-xr-x   2 root     root         1024 Dec 26 12:43 SuSE
-rw-r--r--   1 root     root          512 May 27  1999 boot.0300
-rw-r--r--   1 root     root         4540 Jul 22  1999 boot.b
drwxrwxr-x   2 root     root         1024 Oct 24 15:09 caldera
-rw-r--r--   1 root     root          612 Jul 22  1999 chain.b
drwxrwxr-x   2 root     root         1024 May 28  1999 debian
drwxr-xr-x   2 root     root         1024 Jun  2  1999 lost+found
drwxrwxr-x   2 root     root         1024 Oct 23 15:46 mandrake
-rw-------   1 root     root        51200 Dec 26 18:17 map
-rw-r--r--   1 root     root          620 Jul 22  1999 os2_d.b
drwxrwxr-x   2 root     root         1024 Aug 19 00:11 slackware


Keeping all the kernels here, ensures they remain below the 1024th cyl
even though the root partition is somewhere else.

Here's my lilo.conf -

#
#   NOTE!  Be sure to run lilo like this:
#             $ /sbin/lilo -C /mnt/lilo/lilo.conf
#
#          Where /mnt/lilo is /dev/hda1
#          and /boot is /dev/hda2
#
#               /dev/hdb == CD-ROM
#
#    Current distros / mount points are:
#               /dev/hda1       LILO    /mnt/lilo (shared, but not automount)
#               /dev/hda2       BOOT    /boot (shared)
#               /dev/hda4       SOLARIS
#               /dev/hda3       SWAP    (shared)
#               /dev/hdc1       Ret Hat 6.0
#               /dev/hdc2       Debian
#               /dev/hdc3       unused  (type==82 swap/Solaris)
#               /dev/hdc4       extended partition
#               /dev/hdc5       Caldera
#               /dev/hdc6       Slackware
#               /dev/hdc7       Mandrake 6.0
#               /dev/hdc8       SuSE 6.2
#                  :
#               /dev/hdc12      HOME    /home
#

boot=/dev/hda
map=/boot/map
install=/boot/boot.b
prompt
timeout=500
#
#   Default kernel
#
image=/boot/RH60/vmlinuz-2.2.5-15
        label=RH60
        root=/dev/hdc1
        read-only
#
#   additional entries
#
image=/boot/caldera/vmlinuz
        label=caldera
        root=/dev/hdc5
        read-only

image=/boot/debian/vmlinuz-2.0.36
        label=debian
        root=/dev/hdc2
        read-only

#
#   Solaris
#
other=/dev/hda4
        label=solaris
        loader=/boot/chain.b
        unsafe

#
#  Slackware
#
image=/boot/slackware/vmlinuz
        label=slackware
        root=/dev/hdc6
        read-only

#
#  Mandrake
#
image=/boot/mandrake/vmlinuz
        label=mandrake
        root=/dev/hdc7
        read-only
#
#  SuSE
#
image=/boot/SuSE/vmlinuz
        label=suse
        root=/dev/hdc8
        read-only



For each distro, only /dev/hdc12 (/home), /dev/hda2 (/boot), the distro
root (/), and swap (/dev/hda3) are automounted.

When I install a new distro or update a kernel, I manually mount
the lilo partition under /mnt/lilo.  Then I copy the kernel to
/boot/distro_name/ and edit /mnt/lilo/lilo.conf (NOT /etc/lilo.conf)
if necessary.

Finally, I run lilo with the -C arg (see the comments in lilo.conf above)
and reboot.

This is a great way to try other distros! (I bought a cheapbytes mondo
pack last time out)  I still have to load TurboLinux and Stampede among
others.  Eventually I'll get to some *BSD's.  If you can build up a spare
box, I highly recommend it!