Subject: Re: should sysinst change MBR_PTYPE_386BSD to MBR_PTYPE_NETBSD?
To: <>
From: David Laight <>
List: tech-install
Date: 06/16/2003 13:05:18
>   | You can't do that, there are restriction on what the extended partition
>   | can describe.  You have to create the mbr extended partition and then
>   | transfer the info to the netbsd disklable.
> No, you don't - you can do it in either order, once it is all written
> no-one can tell which block got put there first.   Obviously things need
> to conform to the various constraints imposed (by MBR rules on i386,
> cylinder boundaries on suns, etc) but that's different from "create
> the MBR first".

Let's put it another way, to do anything else would require the disklabel
editing code to know all the mbr rules.  This is (just) plausible if you
are going make each filesystem a separate (extended) mbr partition, but
otherwise it is just too hard.

>   | For i386, the Linux 'one filesystem one partition' scheme isn't stupid!
> It isn't, if one assumes that the MBR should rule.   But BSD (and
> unix in general before that) has been using labels (though they used to be
> in the driver, rather than on the drive) to control the world since before
> MBRs were invented.   In the true unix world, the label rules.

But the disk layout has to be consistent with the machine architecture.
On i386 that means the disks have an mbr that describes where the
filesystems are on the disk....
(This is, in some sense, not dissimilar to what happens on sun systems,
where netbsd uses the sun disklabel format.)

> What's more, to retain the tradition of minimising (hiding) the differences
> between ports as much as possible, that is the way it should stay.  Only
> a few ports use MBR labeling, all of them use the disklabel.

I make it 9 of 32 (known to sysinst).  However I suspect it is most of
the installations.


David Laight: