I have Slackware Linux installed, and am itching to try OpendBSD. I have a couple of spare partitions as follows:

hda = 250G
hda1 = 2G Linux swap
hda2 = Extended (balance of disk)
hda5 = 25G Linux /
hda6 = 25G SPARE
hda7 = 198G Linux /home

hdb = 250G
hdb1 = 2G Linux swap
hdb2 = 124G Linux /mnt/storage
hdb3 = 124G SPARE

Can I safely install OpenBSD without wiping Linux? I'd like to be able to dual boot.

I've read the info on the OpenBSD website, but it doesn't go into too much detail on this point.

*BSD needs to be on a primary partition, so hdb3 looks like your man. It won't touch your Linux installation (unless you tell it to...).

Thanks mate.

i would recommend that you redo hda6 to be hda3 as a primary partition... if you use cfdisk frominside slackware, it will be much easier for you during the openbsd installation. just make hda6 a single, primary partition of type A6 (OpenBSD)

as for booting openbsd... it's quite simple, if you use grub.. i know slackware defaults to lilo.. but you basically treat it like windows.
That should give you trouble booting openbsd from grub.

good luck.

damn duplicates!

Yes and no. As a fellow Slacker who multiboots a bunch of Linux distros with OpenBSD, I would offer the following free-and-completely-without-obligation advice:

Don't go too crazy with a huge partition. OpenBSD is skinnier for the same level of functionality as Linux. My OpenBSD 3.8 desktop machine was half the size of my Slackware desktop machine. 3.9 did get a little fatter, but it's still smaller than a functionally-equivalent Linux. I think 5G for root and maybe a gig per user is a big (huge?) system that you will find hard to outgrow as a desktop or dev machine, but if you are making a music or doc server, only you know how much you will need.

Yes, the dual-booting/Linux coexistence info I've seen on OpenBSD is outdated and borders on the ill-advised. It's very easy to do this, especially as you probably use Lilo since you are Slacking it. Lilo is the way to go. Just add an entry like you would for any other chainloaded OS (or *bloze, for example).

The OpenBSD installation is scary as hell if you are multibooting because *BSD fdisk and disklabel are so foreign to BSD newbies with Linux backgrounds.

Do an fdisk -l in both cylinders and sectors from your Slackware machine, and save it somewhere you can see it, like on a USB drive and/or print it out. Then go to the OpenBSD FAQ and try to understand BSD disklabel as much as you can before you start the installation. This is really the only slippery part and it's key to understanding *BSD installations.

You don't have the option to choose steps in the OpenBSD installation, unlike in the Slackware script. You have to go through every step. The best way to avoid problems is to use Linux fdisk to do all the partitioning, like Halo said. Just exit from the OpenBSD fdisk installation step without saving anything. Then you will go into the disklabel step, which you will have to use. Don't touch partition c! That's *BSD's name for your whole drive. Everything will be in sectors and you should compare it to your printout to make sure you are where you think you are. If you screw up the disklabel, you WILL toast your other systems. a is root, b is swap, and the other partition names are for other mount points. There will also be letters for the other partitions (both primary and extended) that disklabel finds when scanning the drive. Regardless of what OpenBSD doc says, and in the true Slackware tradition, if you are making a desktop machine don't worry about additional mountpoints- just let the system manage the space. If you are making a server, you need to get some advice because I am no sysadmin (yet).

Some jargon:

Linux "partition" = OpenBSD "slice"
OpenBSD "partition" = Linux "mountpoint"

After you exit disklabel, you get an ominous "impending file system destruction" warning. Make sure your disklabel is reasonable (based on your printout in sectors from Linux fdisk -l) and let it go. It will build the filesystem in your partition (*BSD slice).

The FTP installation is pretty cool since there aren't any OpenBSD ISOs except for the boot disk itself. But this is a downer if you have to do it more than once, so what I advise is this (and I just did it to upgrade to 3.9):

Go to a convenient and speedy ftp or http location and download all of the tgz files you will want (I grabbed everything but the games). This should be from the BSD directory (sorry, can't remember the name, and NOT the packages directory!) Make sure you also get bsd and bsd.rd which are the kernels and don't have the .tgz extension. Save this stuff on a USB drive you have formatted ext2 or on an ext2 partition. When it comes time to tell the OpenBSD installer where you want to get the files from, you can point at your already downloaded tars and your installation will fly.

I don't know how much RAM you have but if you have at least 512M then 256K of swap is more than enough for both OpenBSD and Slackware desktops. I've never read of anyone going to swap with this kind of RAM on a desktop machine.

Hey Randux, Thanks for your in depth and detailed response.
I installed OpenBSD last night, and thankfully managed to not wreck the rest of my setup! It ended up working fine on hdb3 as suggested above.
Tell me about it!! I stopped the installation a couple of times to re-read the docs before proceeding. I am no stranger to disk partitioning and have a policy of always using the same tool to partition a disk. This is a lesson hard learned, and I still have the doorstop to prove it...

So, using Linux fdisk, I changed the partition type on hdb3 to a6. Then, I was able to skip thru OBSD's fdisk and jump straight into disklabel, which confused the crap out of me to begin with, but makes a lot of sense when you read the docs properly.

It's little wonder they say "No remote holes in the default install".... There's nothing else in the default install either....

The first two things I've installed are bash and mc. I never realised how much I depend upon features like command history and tab completion. ksh has made me appreciate bash a lot more, and that is after only having used it for 20-odd minutes!

This is fun! I'll try to get my wireless NIC working tomorrow. Free software rocks.

Thanks again.

Indeed. How could anyone live without them? It's amazing what Windows users put up with. (click, click, click, click, "Duh, you stupid piece of ...", <cancel>, click, click, ...).

HA! Now go and, ahem, "use" a DOS box in Windows, see how much fun that is!

Actually ksh has most, if not all, of the features bash has (certainly it has tab completion, history etc), but they may not be enabled by default, for some reason. Indeed, whenever I've used ksh, they haven't been, which gives you the impression that it's only a basic shell. It just takes some configuration. I use zsh (which was modelled on ksh) and it took me days to get the basic functionality working (and 6 years later, I'm still tweaking... ).

Congrats on joining the most exclusive group on x86- OpenSlackers (tm) Too bad I didn't get you the info in time but I see you made out fine without it.

This is a good policy; don't be afraid to bail out if something doesn't feel right. If more people did like that there would be less toasted disk drives in the world.

I'm sure once you know ksh and csh they're fine. But I run too many desktops (and I'm too friggin' old) to be fluent in multiple shells. I can't stand the default shell setup, the prompts, everything just feels wrong. I also grab bash and emacs (although it's very cool that OpenBSD comes with mg (emacs-like mini-editor) so I can do what I need without VI). zsh like ioerror uses is supposed to be even hotter, but you can't go wrong with bash as right now it's probably the most commonly-used shell in the *NIX world.

The OpenBSD team spent a lot of effort on hardware drivers. Your wireless should work in this release.

Correction: OpenBSD rocks!

See ya,

Randux

OK, according to the output of ifconfig and dmesg, my wifi NIC is supported. However, I'm having difficulties working out how to get it to play with my WPA-enabled AP. Under Linux I use wpa_supplicant, but it appears that there is no such animal for OBSD. Can anyone offer any pointers?

Nevermind. The driver for my card (ath) doesn't support WPA yet.

I don't really understand what you're saying, but if the problem is at the application level you may still be able to get it to work since OpenBSD supports execution of Linux and other executables via kernel options.

According to "man ath":
Mine is an AR5212 chipset.

I'll try installing wpa_supplicant anyhow and see if it works. How does this "Linux compatibility" mode work?

Edit: It won't work because wpa_supplicant doesn't support OBSD's driver for my chipset. Oh well. Back to WEP we go!

Downer. If you send your dmesg in maybe it will encourage them to support your driver.

I get the feeling it's a work in progress. If I've understood correctly, the guy who wrote the Madwifi drivers is working for OpenBSD now. So, I'm guessing (and hoping) that WPA support will be along real soon.

Gee, OBSD is very different to Slackware! So far, OBSD seems more obscure, but that is probably because I'm so used to Slack. Speaking of which: Why do they say that Slackware has a BSD style init? The two are poles apart...

How does the OSBD kernel work? I've read that Theo recommends against re-compiling a custom kernel, but have also noticed that the thing weighs in at 5 megs. Does it use kernel modules at all? Or are all the drivers built in?

I am enjoying it all so far, everything is working well. As soon as I switched my router over to WEP, the wireless NIC started working. Sound & video worked out of the box - X even worked without a config file!

Thanks to everyone who replied.