Subject: Re: Partition tables (was: Re: Another changer, another changer
To: David Holland <>
From: Bill Studenmund <skippy@macro.Stanford.EDU>
List: current-users
Date: 10/19/1998 10:17:06
On Fri, 16 Oct 1998, David Holland wrote:

> Wait, which problem are you trying to solve? There are at least the
> following related issues involved here:
>   1. getting disklabel handling code out of disk device drivers

Could you please show me where in the code the disk drivers have knowledge
of the disklabel? They have knowledge of a structure in memory which tells
them info about the disk, and tells them that partition X starts at point
Y and has length Z. They also know a max # of partitions, and that
partition RAWPART is special - it bypasses the start-length table. They do
NOT know about the on-disk disklabel.  All of that is in a machine-dep
routine called readdisklabel() (and writedisklabel()). 

The drivers are always going to need to know some information about the
partition layout, so letting them have at the disklabel structure doesn't
seem too bad. But we're already at a point where, if we wanted to get
fancy with disklabel libraries, we just have to change that one routine.

If there's something I've missed, please let me know.

Take care,