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Windows operating systems, both 9x-based and NT-based, must go first on the hard drive. I suggest giving these operating systems a C: drive of 7GB or smaller. (Remember, early versions of Windows only support 2GB drives, so this won’t be a problem.) If you put a 500MB OpenBSD root file system directly after your Windows partition, you can easily fit it within the 8GB limit. Subsequent OpenBSD file systems should follow immediately afterward. Because OpenBSD can only use a single MBR partition, you need put all your OpenBSD partitions immediately after that. If you have disk space left you can add a third MBR partition to the hard drive after your OpenBSD install and use this for a Windows D: drive or even install Linux or FreeBSD for a triple-boot system.

When installing OpenBSD with FreeBSD or Linux, I recommend putting OpenBSD first on the hard drive and installing the other operating systems further out on the disk.

• The root partition must be completely contained within the first 8GB of disk.
• There can only be one OpenBSD MBR partition per hard disk.

Various operating systems have restrictions on how they may be placed on the disk. Here is a brief overview of these restrictions for the operating systems discussed here. Note that this sort of information may change rapidly, especially for the open-source operating systems! Also, if you search the Internet, you will find suggestions for getting around all of these limitations. Most of these suggestions are very complicated and unsupportable, and if I recommended them my email would be flooded by people who couldn’t make them work. Others cost money. Feel free to seek out these methods and try them yourself, but you’re on your own.

Every operating system includes tools to manage MBR partitions. Unfortunately, every operating system handles MBR partitions in a slightly different manner. More unfortunately, most of these tools are named “fdisk.” Each tool operates differently, and while some of them look similar or have a common heritage they are not guaranteed to be interoperable. The upshot of all this is that you should create the MBR partitions used by an operating system by the operating system’s native tools. When you’re installing a dual-boot OpenBSD/XP system, use OpenBSD’s fdisk(8) to create the MBR partitions only for OpenBSD and use the Windows XP installer to create the partition for Windows XP. Do not use the OpenBSD fdisk tool to create Windows XP partitions, and do not try to create OpenBSD partitions with XP! This might look workable, but minor differences between fdisk implementations might make the partition unusable.

Because this is an OpenBSD book, we’ll focus on OpenBSD’s fdisk. Check the documentation for the other operating systems you’re using for details on their fdisk implementations. The concepts are the same, but many of the details differ.

We discussed OpenBSD partitions and briefly mentioned MBR partitions. You didn’t need to worry about MBR partitions unless you wanted to have multiple operating systems on one computer. The Master Boot Record includes some basic disk partitioning information, marking the locations of up to four partitions.

These partitions are used for different purposes in different operating systems. Windows-based operating systems use these as “logical drives.” If you’re old enough, you’ll remember when a Windows 95 computer could only have a 2GB C: drive, and if you had a larger disk you needed to split it up into logical drives. At one point I had Windows C:, D:, E:, and F: drives on one 8GB hard drive!

OpenBSD, Linux, and FreeBSD all like to support more than four partitions on a drive. They have to have their own partitioning scheme within a single MBR partition. For example, when you have a dedicated OpenBSD machine with five partitions (/, swap, /tmp, /var, /usr, and home), these partitions are all subdivisions of a single MBR partition. That MBR partition just happens to fill the whole disk. OpenBSD partitions need to go within a single MBR partition.

Dedicate a single MBR partition to each operating system on a hard drive. (If you need more than four operating systems, you need to invest in a commercial product that will let you do so.)

Hang on, you’re almost there! Now that you have the files on your disk, you just need to answer a few last questions.

Do you expect to run the X Window System? [y]

Answering “y” enables the kernel settings for running an X server locally. If you plan to have the GUI running on this system, answer “y.” If you are using this machine without a GUI, answer “n”. You can use X remotely on this system without a GUI, you simply cannot run the local XFree86 server.

Saving configuration files......done.
Generating initial host.random file ......done.
What timezone are you in? ('?' for list) [US/Pacific]

The installer will easily set your initial time zone for you. If you don’t know your correct time zone, enter a question mark. The installer will list the time zones it knows of and allow you to choose one. OpenBSD expects the BIOS clock to be set in UCT.

After choosing your time zone, you will see a flurry of messages as the install rebuilds device nodes, installs bootblocks, and in general cleans up after itself. Finally, you will see the completion message.

CONGRATULATIONS! Your OpenBSD install has been successfully completed!
To boot the new system, enter halt at the command prompt. Once the
system has halted, reset the machine and boot from the disk.
# halt

Enter the word “halt,” and the system will shut itself down. Do not just power off the computer! You want to shut the system down gracefully.

syncing disks... done

The operating system has halted.
Please press any key to reboot.

One press of the ANY key, and your system will reboot into OpenBSD!

If you have downloaded the installation sets to a local FTP server or have built some other local installation media, the OpenBSD installer allows you to add your own custom files or scripts to the install process. This is very useful if you have a “standard build” for your network and want to replicate one set of changes to every freshly installed machine.

The installation script looks for a set called “siteXX.tgz” in the same directory as the other distribution sets. Replace the “XX” with the release name — for example, a custom site file for OpenBSD 3.3 would be called “site33.tgz.” This file is a standard gzipped tar file rooted in /. This file is extracted last, using the standard xvpf options, allowing the administrator to add custom files or packages  to every system installed with that set.

As a final step in the install process, the installer will look for a shell script called /install.site. If such a script is found, it is run as the last stage of the install process. You can use this to remove unwanted programs, install other software or any other actions desired. The easiest way to get /install.site onto your new system is to include it in siteXX.tgz.

Now that you know where you are installing from, you can choose what to install. The installer will present a list of all the distribution sets available in this version of OpenBSD.

The following sets are available. Enter a filename, 'all' to select
all the sets, or 'done'. You may de-select a set by prepending a '-'
to its name.

        [X] base32.tgz
        [X] etc32.tgz
        [X] misc32.tgz
        [X] comp32.tgz
        [X] man32.tgz
        [X] game32.tgz
        [ ] xbase32.tgz
        [ ] xshare32.tgz
        [ ] xfont32.tgz
        [ ] xserv32.tgz
        [X] bsd

File Name? (or 'done') [xbase32.tgz] all

The defaults shown are a reasonable choice for a server without the X Window System. If you’re satisfied with these choices, you can just enter “done”. To install a complete set of OpenBSD, including X, enter the name “all.” If you want something in between, such as adding one distribution set to the list, type its name.

File Name? (or 'done') [xbase32.tgz] xshare32.tgz

To remove a distribution set, enter its name with a leading -.

File Name? (or 'done') [xbase32.tgz] -man32.tgz

After each modification, the installer will present you with an updated lists of distribution sets it will install. When you’re happy with the list, type “done” and ENTER. You’ll get a final chance to change your mind.

Ready to install sets? [y]

Hit ENTER, and the installer will begin writing OpenBSD from the installation media onto your hard drive. You’ll see a message much like this for each distribution set you chose to install.

Getting etc32.tgz ...
 54% |***************************                |  793 KB   00:04 ETA

This will go very quickly if you’re installing from CD-ROM, and at network speeds otherwise.

Once the distribution sets you chose are installed, you’ll have an opportunity to change your mind and add more distribution sets. This can be useful if a network site you installed from did not have all the sets you needed or if network issues prevented you from downloading them.

Extract more sets? [n]