Subject: RE: Booting sd0 (disk geometry versus bios geometry)
To: None <port-i386@NetBSD.ORG>
From: Gunnar Helliesen <gunnar@bitcon.no>
List: port-i386
Date: 07/15/1998 02:17:41
D.Thomas@vthrc.uq.edu.au wrote:
> 
> >Any reason why this is a bad idea? Any reason why sysinst 
> couldn't just
> >assume 1024/16/63 for the MBR on all machines with large 
> disks (>503 MB)
> >in case the user wants to use the entire disk for NetBSD? If 
> he doesn't,
> >sysinst could just grab the geometry from the existing MBR. 
> In any case
> >this stuff should be hidden from the user.
> 
> ummm because that geometry doesn't match that of the MBR ?

I wasn't clear, sorry. What I meant was:

- Assume this is a blank disk
- Assume the user has said he wants to use the whole disk for NetBSD (in
which case any existing MBR doesn't matter much anyway)
- Assume the disk is larger than the 1024/16/63 limit

In that case, why can't sysinst just write an MBR with 1024/16/63
geometry and be done with it?

> This matters when you use (p)fdisk to set up several 
> partitions, one for
> each operating-system. You want a translated geometry so OS partitions
> after the physical 1024'th cylinder can be booted.

In that case we could:

a) Look for an existing MBR and read the geometry from it. Ask the user
if it's correct/what he wants
b) If he replies "no", ask him to supply a geometry and partition sizes
etc.

Gunnar

--
Gunnar Helliesen   | Bergen IT Consult AS  | NetBSD/VAX on a uVAX II
Systems Consultant | Bergen, Norway        | '86 Jaguar Sovereign 4.2
gunnar@bitcon.no   | http://www.bitcon.no/ | '73 Mercedes 280 (240D)