Xenix upgrade horror story

[Roger Knopf 5502]

In article <1990Jul19.101125.245 at bbt.se> pgd at bbt.se (P.Garbha) writes:

[various symptoms deleted]

I agree with Ross, it sounds like your Xenix partition extends 
beyond 1024 cylinders. Since there is no standard way of handling
>1024 cylinders in the BIOS (some do, some don't), and our boot
code uses the BIOS, when either /boot (I suspect in this case) or
/xenix ends up all or partly on cylinders >1024, things will behave
very oddly when booting. The high-order bits of the cylinder number
are essentially masked off so you are reading /boot from somewhere
other than where it _really_ resides.

Most controllers and disks that have >1024 cylinders have a format
option that will remap the disk to less cylinders, more heads and
sectors. I suggest you either look into that option (for long term
satisfaction). Making sure that /boot and /xenix are within 1024
cylinders can only (easily) be guaranteed by making your root
file system within the first 1024 cylinders of the hard disk.
 
>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. 
 
Actually, this has nothing to do with serialization and we do not
do anything like write the serial number on the file system. 

-- 
Roger Knopf                                      <standard disclaimer applies>
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