Subject: Re: Some help with disklabel please?
To: Jason Thorpe <thorpej@nas.nasa.gov>
From: Eduardo E. Horvath eeh@btr.com <eeh@btr.btr.com>
List: current-users
Date: 08/10/1995 09:30:47
On Wed, 9 Aug 1995, Jason Thorpe wrote:

> On Wed, 9 Aug 1995 19:59:15 -0700 (PDT) 
>  wrstuden@loki.stanford.edu (Bill Studenmund) wrote:

>  > > Another point to make here, I suppose, is that not all ports that use 
>  > > NetBSD-format disklabels keep them in the same place (for various 
>  > > reasons).  Just something else to think about :-)
>  > 
>  > Can they be told apart?
> 
> Huh?  I assume you mean ``Is it easy to tell the difference between them?''
> Umm .. the _is_ no difference between them, except for the size of the 
> partition map in them.  For example, the MAXPARTITIONS value on the hp300 
> is 8, but on the Amiga it's 16.  This means that sizeof(struct disklabel) 
> is different on these platforms.  So, the disklabel checksums will be 
> wrong if an hp300 reads an amiga's disklabel, since it won't read the 
> whole disklabel ... The biggest problem is _finding_ the disklabels...

The Amiga port synthesizes a disklavel from ther RDB structure
AmigaDOS uses for disk partitioning.  There is no real disklabel on
the disk and the kernel does not support writing one.  (You could
probably write one using the raw device, but I don't think the kernel
would ever try to read it.)