The contribution from Marc Tanguy (email@example.com), 21 Jul 2001
Actually, it exists two ways to know it :
If you have an adaptec scsi card (2940u2, 29160, 39160), you simply use the 'diagnose' mode. It must be activated in the scsi card BIOS. Then you just have to wait and see something like :
... ID - LUN - Vendor - Product - Rev - Size - Sync - Bus - HD# ... 0 - 0 - QUANTUM - ATLAS10K2 - DDD6 - 17GB - 160 - 16 - 80h ... 1 - 0 - QUANTUM - ATLAS10K2 - DDD6 - 17GB - 160 - 16 - 81h ... 2 - 0 - IBM - DDRS - DC1B - 4GB - 80 - 16 - 82h ... 3 - 0 - IBM - DNES - SAH0 - 9GB - 80 - 16 - 83h | The values we want are here -------------------------------------
If you don't own an adaptec card (which is bad luck), you have two know what is the 'booting' disk (usually ID 0, but not necessary, it must be define in the scsi card BIOS) where LILO is going to be found and start : this is the first disk so it has number 0x80, then it's very simple, the BIOS follows the IDs.
By exemple :
ID 0 -> boot -> 0x80 ID 1 -> empty ID 2 -> disk -> 0x81 ID 3 -> disk -> 0x82
ID 0 -> disk -> 0x81 ID 1 -> empty ID 2 -> disk -> 0x82 ID 3 -> boot -> 0x80 ID 4 -> disk -> 0x83
This part doesn't care at all of what is installed on the scsi drives.
** Ok, but NT must be the first disk to boot, so i want it in 0x80, but i already have LILO and a full ext2 only drive on 0x80 and my NT drive is in 0x83. How can i 'swap' linux and NT ?
This a very easy : you just have to tell BIOS that NT drive is now 0x80 and the Linux drive is 0x83.
other=/dev/sdd1 label=nt map-drive = 0x83 to = 0x80 map-drive = 0x80 to = 0x83
This change will produce and warning :
Warning: BIOS drive 0x8? may not be accessible
but if you know what you are doing it will run without problem.
I used it on this configuration which has a Red Hat Linux 7.1 and a Windows 2000 Pro :
Name Flags Part Type FS Type [Label] Size (MB) Disk Drive: /dev/sda sda1 Boot Primary Linux ext2 [/boot] 24.68 sda2 Primary Linux raid autodetect 139.83 sda3 Primary Linux raid autodetect 3150.29 sda4 Primary Linux ext2 [/home] 15044.04 Disk Drive: /dev/sdb sdb1 Primary Linux raid autodetect 139.83 sdb2 Primary Linux raid autodetect 3150.29 sdb3 Primary Linux ext2 [/] 1052.84 sdb4 Primary Linux ext2 [/public] 14015.88 Disk Drive: /dev/sdc sdc1 Boot Primary Linux ext2 [/var] 1052.84 sdc2 Primary Linux ext2 [/tmp] 106.93 sdc3 Primary Linux ext2 [/cache] 1052.84 sdc4 Primary Linux ext2 [/chroot] 2352.44 Disk Drive: /dev/sdd sdd1 Boot Primary NTFS [A] 9162.97
My full /etc/lilo.conf :
boot=/dev/sda map=/boot/map install=/boot/boot.b prompt default=Linux read-only compact image=/boot/vmlinuz label=Linux root=/dev/sdb3 other=/dev/sdd1 label=nt map-drive = 0x83 to = 0x80 map-drive = 0x80 to = 0x83
** I just plugged a new scsi drive, and now LILO refuse to boot, what's going on ?
When you plug a disk, you must be careful with the IDs. If you add a drive between two already plugged disks the BIOS numbers are changed :
Before ----> After scsi id - - BIOS id scsi id - - BIOS id ID 0 - disk - 0x80 ID 0 - disk - 0x80 ID 1 - empty ID 1 - new disk - 0x81 ID 2 - disk - 0x81 ID 2 - disk - 0x82 !!
If you change the BIOS ids, you have to re-evaluate them.