diff options
| -rw-r--r-- | etc/etc.i386/INSTALL.linux | 131 |
1 files changed, 46 insertions, 85 deletions
diff --git a/etc/etc.i386/INSTALL.linux b/etc/etc.i386/INSTALL.linux index c85c44be2a6..a2e2a375d8e 100644 --- a/etc/etc.i386/INSTALL.linux +++ b/etc/etc.i386/INSTALL.linux @@ -1,29 +1,29 @@ -$OpenBSD: INSTALL.linux,v 1.11 2002/06/09 06:15:14 todd Exp $ +$OpenBSD: INSTALL.linux,v 1.12 2004/08/18 08:57:33 espie Exp $ Linux + OpenBSD: it's possible - by Marc Espie -- espie@cvs.OpenBSD.org + by Marc Espie -- espie@OpenBSD.org + recent information by Tim Kornau -- opti@openbsd.de It is perfectly possible to have Linux and OpenBSD on the same disk. -As of this writing (OpenBSD 2.5 & linux 2.2.3), both can read and write -other partitions, though Linux's support of BSD filesystems is still -experimental. Please note that 2.0 linux kernels, and most 2.1 kernels -don't know how to handle OpenBSD partitions (other BSD partitions are type -A5 and differ significantly from OpenBSD partitions--type A6). +Both can read and write other partitions. You can even install OpenBSD from an ext2fs partition (choose install from disk... ext2fs does not appear in the choices, but `default' it is). If you are starting from scratch, it is better to install Linux first. -Since you are going to use several OSes, you need a way to multi-boot, and -Linux's lilo fits the bill fine. +Since you are going to use several OSes, you need a way to multi-boot. +If you keep Windows NT (or XP) on the disk, its multi-booter can deal +with OpenBSD (see the FAQ). Otherwise Linux's lilo fits the bill fine. +Recent versions of GRUB can also multiboot OpenBSD. -IMPORTANT: don't forget about lilo. You can't uninstall linux from this -disk without *first* restoring the MBR to an un-liloed state and making -*dead* sure OpenBSD boots as a default. +IMPORTANT: don't forget about lilo. If you use lilo, you can't uninstall +linux from this disk without *first* restoring the MBR to an +un-liloed state and making *dead* sure OpenBSD boots as a default. -If you want to grab space from a Windows/DOS partition, use fips. +If you want to grab space from an older Windows/DOS partition, use fips. Fips20 knows all about FAT32, so windows 95 is no longer a problem. +Or use the commercial offering Partition Magic. Other sources of information, especially concerning other BSD systems, must be taken with a healthy dose of skepticism. OpenBSD definitely @@ -84,30 +84,6 @@ They know more about its internal workings than you do. So use linux fdisk for linux partitions, don't let it touch the OpenBSD disklabel, and reciprocally. -DOS and BIOS and all the problems of the world ----------------------------------------------- -Due to historical accident, your machine resident `Operating System', -also known as the BIOS, can only access hard-disks up to cylinder 1024. -Various lying tricks are used, so that your whole disk is usually -accessible to the BIOS, except for very large disks (>8Gb). - -fdisk is usually going to give you reliable information: anything that is -before cylinder 1024 can be accessed through the BIOS. - -When you first boot up OpenBSD, the kernel will detect your hardware, -and give you a message such as - wd0 at wdc0 drive 0: <TOSHIBA MK4006MAV> - wd0: 3909MB, 7944 cyl, 16 head, 63 sec, 512 bytes/sec, 8007552 sec total - wd0: using 16-sector 16-bit pio transfers, lba addressing -don't panic. This is just the real disk geometry. Trust fdisk on this one. - -If fdisk shows you more than 1024 cylinders, you will have to cram OpenBSD -into that. Actually, it's enough that the disklabel partition used for -booting fits within the first 1024 cylinders (a:), so if you can get your -OpenBSD partition to start within 1024 cylinders, just get a small enough -a:, and you're in the clear. (You can get by with a: a bit under 20Mb, -BTW, just enough for /bin /sbin, a kernel and /etc). - Mapping your disk ----------------- Starting from Linux, get a grasp of your partitions. Use df to check which @@ -128,8 +104,6 @@ The + at the end of the DOS line is because linux fdisk is brain-damaged and wants to write output in 1024-sized chunks, so this stands for `850720 blocks and a half' -Older flavors of linux fdisk won't recognize a6 as OpenBSD. - As you can see, my linux setup is very small. I have enough to check how things such as gcc work on linux, but my machine is definitely an OpenBSD developer's box. @@ -203,20 +177,6 @@ hwclock --systohc --utc. Normally, this is one of the choices that the Linux installation program lets you do: set your hardware clock to GMT. -The Linux partition table and OpenBSD -------------------------------------- -There used to be a problem with Linux's rc: it always mounts all file systems -even in single-user mode. The 2.2 kernels fix that in a handy way: the -partition recorded in the MBR is scanned for a disklabel, and marked with -a ! if one is found. Then, the rest of the disk is scanned, before -coming back to the disklabel itself. That way, changes to the -OpenBSD disklabel won't affect the setup of the rest of the disk. - -Anyhow, you may want to check that you can still boot from a Linux kernel -which doesn't know about disklabels. The long term solution is to fix your -inittab and rc scripts to make deadly sure that single-user boot will work --- preferably by moving disk mounts to multi-user. - The OpenBSD installation ------------------------ If you've got the space, you can install from your ext2fs partitions. This @@ -347,8 +307,33 @@ Once the disklabel is written to disk, the installation proceeds as usual. ext2fs partitions are perfectly usable from OpenBSD. -Booting -------- +Booting with GRUB +----------------- +Here is a sample configuration for a linux 2.4, linux 2.6, OpenBSD 3.6, +WindowsXP + +timeout 30 +default 0 +fallback 1 + +title OpenBSD +rootnoverify (hd0,3) +makeactive +chainloader +1 + +title WinOS +rootnoverify (hd0,0) +chainloader +1 + +title Debian GNU/Linux, kernel +root (hd0,2) +kernel /boot/vmlinuz root=/dev/ide/host0/bus0/target0/lun0/part3 ro +savedefault +boot + + +Booting with lilo +----------------- First time I booted my system back, I did not get into OpenBSD as expected... I plain forgot I had installed lilo in the master boot block, and lilo does not heed the active partition flag. The fix was rather simple: from @@ -367,25 +352,16 @@ image=/boot/vmlinuz-2.2.3 vga=4 root=/dev/hda2 read-only -image=/boot/vmlinuz-2.0.36-0.7 - label=linux.orig - root=/dev/hda2 - read-only other=/dev/hda1 label=dos table=/dev/hda -More details: I've kept the original redhat installation as -vmlinuz-2.0.36 because I'm paranoid, but the real setup uses only -bsd, linux, and dos. - Rerun lilo (DON'T FORGET THAT STEP), and voila, OpenBSD is able to boot! Linux and OpenBSD partitions ---------------------------- -The 2.2 kernel does incorporate my patch for the correct handling of -OpenBSD partitions. You will probably need to reconfigure and rebuild -your linux kernel to recognize BSD disklabels... Here is how it shows up +You will probably need to reconfigure and rebuild your linux kernel +to recognize BSD disklabels... Here is how it shows up on my box: Partition check: @@ -410,7 +386,7 @@ and here is my linux fstab: /dev/fd0 /mnt/floppy ext2 noauto 0 0 /dev/cdrom /mnt/cdrom iso9660 noauto,ro -2.2 kernels also include a working UFS, though you may run into problems when +linux kernels also include a working UFS, though you may run into problems when writing to ufs partitions. Note the ufstype=44bsd. If you forget that in your mounts, it will fail. Depending upon your installation, you may get a failure message, or you will have to dig through /var/log/ to find @@ -484,30 +460,15 @@ you know what you are doing, and don't expect there will always be someone to get you out of trouble. If your setup is really too weird, no-one can help. As far as the boot process goes, I think lilo allows you to boot from ANY -partition recorded in the MBR, including extended partitions. The only -limitation is that the next stage bootstrap MUST take place entirely within -the first 1024 cylinders of the disk, as seen by the BIOS. OpenBSD -MBR partitions that extend beyond cylinder 1024 are no problem, as long as -the disklabel root (a) partition doesn't extend beyond cylinder 1024. - -Since Windows, OpenBSD, and linux all have that limitation, the easiest way -is to start with Windows partitions (entirely within the first 1024 -cylinders), follow with the linux boot partition (still within the first -1024 cylinders), then the OpenBSD area (which can span the 1024 cylinders -boundary, as long as a lives within the limit), and the remaining linux -partitions. - -Weirder setups are unwarranted. Several bsd on the same disk MAY be -possible, but will be harder to manage: +partition recorded in the MBR, including extended partitions. + +Several bsd on the same disk MAY be possible, but will be harder to manage: - it is better if disklabels match, - linux will obey the first disklabel it finds, try to ensure this is OpenBSD disklabel, it can describe more partitions than the others, - other BSD may get confused with each other data. Normally, the A5/A6 split ensures that Net/Free won't get mixed up with OpenBSD, - FreeBSD and NetBSD will probably get confused with each other, -- if you have a 1024 cylinder limit, all boot areas must stay within the -1024 cylinder boundary, so only one of the BSD may span that limit, apart -from very, very nasty tricks. Finally, how much disk space do you have anyway ? Do you really need to cram that many OSes on the same disk ? Put them on separate disks rather. |