Xenix upgrade horror story

[P.Garbha]

Yesterday i got my upgrade (new version) of xenix. It seems like it
does not give you any easy way of upgrading -- you have to reinstall.
But i thought that i could handle it anyway.
So i just copied over all the new system files, unto the old (running)
version of xenix, installed the new link kit, re-linked the kernel,
and thought that that was it.

Now what happend was that Xenix suddenly was unbootable. I could not
even boot the old kernel any more. They all gave variations of error
messages, one of:
*) Bad magic number, and returning the the boot prompt
*) Illegal segment 32767, (or something), and return to the boot
   prompt
*) bn 1, bn 2, .... bn256, and blank screen and cold reboot
Note, there is NOTHING wrong with the kernel files, since one of the
errors come, even if i copy a kernel from an old, bootable,
"emergency boot" floppy.

Fortunately i managed to boot one version of the kernel. Not the old
one, but one that was mistakenly generated when i installed my
multiple-port serial board. It gave messages like "bn 1, bn 2, ... bn
127", but it booted.

After that i just had to surrender, copy the whole system with tar to
a set of backup tapes, install the new version the "real" way, and
copy back the tapes. Now it works again.

My suspicion is that this trouble all comes from serialization. My
old version of xenix had a different serial number than the new one,
and somehow or another it detects that the file system was installed
with another serial number, and therefore did not work. 

I still get one "bn 2" (or something) message at boot time, and would
very much like to know what it means.

(After this i fell a string itch in my fingers, to hack away the
serialization code from the kernel. It for sure does not give me
anything but trouble.)