This is a system made up of an assortment of odds and ends. The root mounted raid device is comprised of a RAID1 made up of one RAID0 array from odd sized disks and a larger regular disk partition. Examination of the lilo.conf files may give you better insight into the reasoning behind the various parameters.
/dev/md0 is the /boot partition and is autostarted by the kernel
/dev/md1 is one half of the mirror set for md2, autostarted by kernel
/dev/hda3 is the other half of the mirror set for md2
/dev/md2 is the RAID1 /dev/md1 + /dev/hda3, started by initrd
df
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/md2 138381 74421 56815 57% /
/dev/md0 2011 1360 549 71% /boot
# ----------------------------
fdisk -ul /dev/hda
Disk /dev/hda: 8 heads, 46 sectors, 903 cylinders
Units = sectors of 1 * 512 bytes
Device Boot Start End Blocks Id System
/dev/hda1 46 4415 2185 fd Linux raid autodetect
/dev/hda2 4416 43423 19504 82 Linux swap
/dev/hda3 43424 332303 144440 83 Linux native
# ----------------------------
fdisk -ul /dev/hdc
Disk /dev/hdc: 8 heads, 39 sectors, 762 cylinders
Units = sectors of 1 * 512 bytes
Device Boot Start End Blocks Id System
/dev/hdc1 39 4367 2164+ fd Linux raid autodetect
/dev/hdc2 4368 70199 32916 82 Linux swap
/dev/hdc3 70200 237743 83772 fd Linux raid autodetect
# ----------------------------
fdisk -ul /dev/hdd
Disk /dev/hdd: 4 heads, 39 sectors, 762 cylinders
Units = sectors of 1 * 512 bytes
Device Boot Start End Blocks Id System
/dev/hdd1 39 118871 59416+ fd Linux raid autodetect
# ----------------------------
# raidtab
#
raiddev /dev/md0
raid-level 1
nr-raid-disks 2
persistent-superblock 1
chunk-size 8
device /dev/hdc1
raid-disk 1
device /dev/hda1
raid-disk 0
raiddev /dev/md1
raid-level 0
nr-raid-disks 2
persistent-superblock 1
chunk-size 8
device /dev/hdc3
raid-disk 0
device /dev/hdd1
raid-disk 1
raiddev /dev/md2
raid-level 1
nr-raid-disks 2
persistent-superblock 1
chunk-size 8
device /dev/md1
raid-disk 1
device /dev/hda3
raid-disk 0
# ----------------------------
cat linuxrc
#!/bin/sh
# ver 1.02 2-22-00
#
############# really BEGIN 'linuxrc' ###############
#
# mount the proc file system
/bin/mount /proc
# autostart /boot partition and raid0
/bin/raidstart /dev/md2
# tell the console what's happening
/bin/cat /proc/mdstat
# Everything is fine, let the kernel mount /dev/md2
# tell the kernel to switch to /dev/md2 as the /root device
# The 0x900 value is the device number calculated by:
# 256*major_device_number + minor_device number
echo "/dev/md2 mounted on root"
echo 0x902>/proc/sys/kernel/real-root-dev
# umount /proc to deallocate initrd device ram space
/bin/umount /proc
exit
# ----------------------------
contents of initrd.gz
./bin
./bin/ash
./bin/echo
./bin/raidstart
./bin/mount
./bin/umount
./bin/cat
./bin/sh
./dev/tty1
./dev/md0
./dev/md1
./dev/md2
./dev/md3
./dev/console
./dev/hda
./dev/hda1
./dev/hda2
./dev/hda3
./dev/hdc
./dev/hdc1
./dev/hdc2
./dev/hdc3
./dev/hdd
./dev/hdd1
./dev/hdd2
./dev/hdd3
./dev/initrd
./dev/ram0
./dev/ram1
./dev/ram2
./dev/ram3
./dev/ram4
./dev/ram5
./dev/ram6
./dev/ram7
./etc/raidtab
./etc/fstab
./lib/ld-2.1.2.so
./lib/ld-linux.so.1
./lib/ld-linux.so.1.9.9
./lib/ld-linux.so.2
./lib/ld.so
./lib/libc-2.1.2.so
./lib/libc.so.6
./linuxrc
./proc
# ----------------------------
cat lilo.conf.hda
# GLOBAL SECTION
# device containing /boot directory
disk=/dev/md2
# geometry
bios=0x80
cylinders=903
heads=8
sectors=46
# geometry for 2nd disk
# bios will be the same because it will have to be moved to hda
# cylinders=762
# heads=8
# sectors=39
# dummy
partition=/dev/md0
# start of device "disk" above
start=46
# second device
# start=39
# seem to have some trouble with 2.2.14 recognizing the right IRQ
append = "ide1=0x170,0x376,12 ether=10,0x300,eth0 ether=5,0x320,eth1"
boot=/dev/hda
map=/boot/map
install=/boot/boot.b
initrd=/boot/initrd.gz
image=/boot/zImage
root=/dev/md2
label=LinuxRaid
read-only
# ----------------------------
cat lilo.conf.hdc
# GLOBAL SECTION
# device containing /boot directory
disk=/dev/md2
# geometry
bios=0x80
# cylinders=903
# heads=8
# sectors=46
# geometry for 2nd disk
# bios will be the same because it will have to be moved to hda
cylinders=762
heads=8
sectors=39
# dummy
partition=/dev/md0
# start of device "disk" above
# start=46
# second device
start=39
# seem to have some trouble with 2.2.14 recognizing the right IRQ
append = "ide1=0x170,0x376,12 ether=10,0x300,eth0 ether=5,0x320,eth1"
boot=/dev/hdc
map=/boot/map
install=/boot/boot.b
initrd=/boot/initrd.gz
image=/boot/zImage
root=/dev/md2
label=LinuxRaid
read-only