Subject: Re: disklabels
To: None <>
From: Bill Studenmund <>
List: current-users
Date: 08/10/1995 10:45:51
>  > Oops! Take a step back. Is there a difference ON DISK? Looking at just
>  > the disk, can't we tell the difference between formats between various
>  > OS's?
> Ummm ... sort of ... You can just read what you think is the right place 
> and look for the right magic numbers, providing the on-disk format that 
> you're reading provides such a mechanism for validating the label.  If 
> not, then you're just second-guessing.

I had in mind a preceeding step where we look to see what OS was used,
_then_ we look at the disklabel. Granted this wording is skewed towards
ports where UNIX is not the native OS.

>  > If all these patterns are different, then we can look for each one in
>  > turn.  If we find one, we know the partitioning scheme in use on the
>  > disk. We then look to the port for that machine and ask it to read the
>  > disklabel, as it already understands this partitioning scheme.
> That's what my code did ... it gave preference to the port's `native' 
> disklabel format, and then jumped though function pointers looking though 
> the other formats until it didn't fail anymore.  If none of them 
> succeeded, `no disk label' was reported and a fake label generated.

So basically my suggestion is that something similar to your code
gets worked into the kernel. :-)

Take care,