> I set up a dual booting OpenBSD/ubuntu (only for the audio, I swear!) > install. I made sure to have the Ubuntu installer make an ext2 data > partition for sharing. For some reason OpenBSd couldn't see the ext2 > partition until I added it manually. I would like to know why.
The exact way that this works is not well documented. Let me explain it here. I don't want to add this to any manual page, sorry. A MBR is found. If inside it we find a A6 partition we look for a disklabel at the right offset. If that disklabel is validated (checksums, etc) then we use that disklabel as read from the disk, exactly as it is. If any of the above fails then we generate a spoofed label. This is filled with information that we find from the MBR. (On other architectures without an MBR, we may also do some other kinds of spoofing). If you read a spoofed label, and modify it and write it out, it becomes a real label for the next boot, as described above. New MBR partitions will not be "noticed". > After adding partition 'n' I can mount and use my data drive fine. My > only guess was that I had too many partitions, but the FAQ says "up to > 'p'") which is greater than 'n' so that's not it. So any ideas why > OpenBSD didn't pick up the data partition on it's own? If you look > closely you'll see that it picked up the ubuntu root drive (as sd0i) > which was also not within the original disklabel(8) "b" limits. It was there originally. The other one was not. Hmm, there may be another problem in that it will only spoof 3 partitions (it should probably be able to spoof more).
