Subject: Re: Disklabel(5)/(8) ??
To: Bill Studenmund <wrstuden@loki.stanford.edu>
From: Hauke Fath <saw@sun0.urz.uni-heidelberg.de>
List: port-mac68k
Date: 10/07/1996 23:43:24
> What are "native" disklabels? If they're different from Apple's partitioning
> stuff, why do we want them?
> 
> Take care,
> 
> Bill

LOL... WHAT? You don't want them? You're gonna get them anyway!  ;-)

A disklabel in *BSD diction is a data structure describing the disk
hardware and the way it is partitioned. 

You are right in that the Macintosh uses a partitioning scheme that is
(at least) equal to the *BSD scheme - IMHO it is more flexible. 
The hardware data stored in a disklabel leads us directly into the Stone
Age of computer history: Track-to-track transition time,
sector/track/cylinder interleave, rpm - you name it, it's there. Look at
disklabel(5) and /etc/disktab. But no way to feed it a zone recorded
disk in a sensible manner - ouch... (Bill, I've read your mail to
tech-kern some months ago, and be assured, I feel _at_least_ as strong
about the issue. It currently hits me full force with the 800K floppy:
8..12 sectors/track at 300-550 rpm.)

But having a *BSD disklabel in a commonly accepted location enables us
to move disks among machines with identical byte order, and that's why
they are wanted. 

And: I need a disklabel on the floppy if I want to put a file system
onto it. Sure, you could always fake it in the kernel the way it is done
for SCSI disks now. But support is there and (with minor tweaks) even
operative, and you can have both: The kernel first looks for a MacOS
magic number, then for *BSD counterpart.

        hauke

-- 
"It's never straight up and down"  (DEVO)