Making a bootable install CD

Most newish i386 computers can boot from the CDROM. These instructions outline how to create a bootable CDROM for installing OpenBSD.

Get your files organised. The OpenBSD installer expects to see a CDROM with a directory structure of /version_number/architecture/, where version_number is the current version, and architecture is i386. For a minimal boot image, all that's needed are the tarred gzipped install files, the bsd kernel, and the cdromxx.fs floppy image.

These files need to be arranged in a directory, e.g.

mkdir OpenBSD
mkdir OpenBSD/2.9
mkdir OpenBSD/2.9/i386
Copy the files into the OpenBSD/2.9/i386 directory.

Now all you need is to use mkisofs to create an iso image. The command to do this is:

mkisofs -r -b 2.9/i386/cdrom29.fs -c "boot.catalog" -o OpenBSD.iso OpenBSD
This command creates a ISO9660 CD with Rock Ridge extensions, which will boot from the floppy image in cdrom29.fs. The image is output to OpenBSD.iso. You can then burn this onto a CDROM with anything that knows how to burn ISO images. I've used cdrecord on OpenBSD, or copied the file onto a Windows box and used the recording software there.

These instructions apply equally well to EmBSD. In the case of EmBSD I downloaded a tar of the whole 1.1 install directory, unpacked it into embsd/1.1/i386, created an ISO and burned it to CD. This makes installing very easy.

Philip Plane