Subject: Re: diskpartitions
To: Jim Reid <jim@mpn.cp.philips.com>
From: Patrick Welche <prlw1@cam.ac.uk>
List: netbsd-help
Date: 06/06/1997 10:29:24
Jim Reid wrote:
> 
> >>>>> "Patrick" == Patrick Welche <prlw1@cam.ac.uk> writes:
> 
>     Patrick> When creating a disktab, do all of NetBSD's partitions
>     Patrick> have to be contiguous?
> 
> No. You can have gaps of unused space - thought you might as well use
> the whole disk. Partitions can also overlap: partitions d and e could
> occupy the same space as partition f (say). Provided you don't use f
> with either d or e, then all will be fine.

Great.

>     Patrick> If not, what do you put in for the offset of partition c?
> 
> I don't understand the question. You should NEVER mess about with
> partition c. By convention, it maps the whole drive. This is useful
> for disk to disk copies. It is also important for things like
> formatting, labelling, bad block handling and the like. Utilities
> open up the c partition to get access to the whole disk, something
> that disk device drivers require so these tasks can be performed.
> If you tamper with the c partition offset and sizes, you might lose
> the ability to relabel the disk or repair bad blocks, so DON'T DO IT!

Well, from the FAQ, I got the impression that c was the size and
offset of the BSD part, and d was the size of the whole disk
(obviously with offset 0). It was what to write in the offset bit of c
given that there might be gaps, and for that matter would the size of
c be all the BSD only bits, or the size including the gaps?! Maybe it
just doesn't matter... Time for trial and error...

Thanks,

  Patrick