Subject: Re: Disklabel(5)/(8) ??
To: Hauke Fath <>
From: The Great Mr. Kurtz \[David A. Gatwood\] <davagatw@Mars.utm.edU>
List: port-mac68k
Date: 10/08/1996 15:03:56
On Tue, 8 Oct 1996, Hauke Fath wrote:

> davagatw@Mars.utm.edU (The Great Mr. Kurtz [David A. Gatwood]) said...
> > Somehow I suspect that using native disklabels would also require a
> > NetBSD-side format program to trash the Apple Partition table, if you
> > wanted to use BSD disklabels, otherwise the disklabel prog would find t=
> > Apple table and read from and write to it.  Either that, or I guess you
> > could just put a --force_native option for the disklabel command....  T=
> > could be messy, though.  Thoughts on that, anyone?
> Dead simple...=20
> 'disklabel -wr sd2 mo230 "My junk disk"' overwrites block 0 of my 230 MB
> magneto-optical with a NetBSD disklabel constructed from the
> /etc/disktab entry 'mo230' and names the 'pack' (*BSD diction) "My junk
> disk". This entry consists of physical disk parameters as well as
> logical partitioning data (see disktab(5)):
> sd230|mo230|mo230-iso|Fujitsu M2512A Magneto-optical:\
>         :ty=3Doptical:dt=3DSCSI:\
>         :ns#40:nt#8:nc#1394:su#446324:se#512:\
>         :pc#446324:oc#0:bc#8192:fc#1024:tc=3Dunused:\
>         :pg#446323:og#1:bg#8192:fg#1024:tg=3D4.2BSD:
I assume that the above tg is to define the label format, which for disks
formatted normally would default to... Macintosh?  Mac4.2BSD?  AUX4.2BSD?

The point I was trying to make (poorly) was that if writing to the MacOS
partition table were supported in the future, some means would be required
to tell disklabel whether it was writing a BSD-type disklabel or a Mac
partition table label, and more importantly, be able to override whatever
was on the disk initially (since the read would use an auto-check).  That
could be done with disktab, but it might be nice to be able to override it
on the command-line.

Which brings up another question: anybody know anything about (or have
sources of info about) "Foreign File Access"?  It'd be nice to be able to
directly mount (under MacOS): 1.  A/UX BSD partitions, 2.  A/UX MkLinux
partitions, and 3. BSD native partitions.

Which brings up yet another question: is there any chance of adding code
to distinguish an ext2fs from a ffs, and perhaps even making MkLinux
partitions mountable under NetBSD (and vice versa)?  Ideas?

> > And PC would probably be comparatively easy, given
> > linux's existing code for dealing with MS-DOS hard drives (and maybe
> > floppies?).  Thoughts?
> Unfortunately, MFM is an entirely different _physical_ format. No way
> without register specs for the SWIM...

Good point.  Hadn't even thought about the fact that IWMs don't do that
sort of thing.  I assume that the SWIM's an Apple proprietary chip, right?


|David A. Gatwood             And Richard Cory, one calm summer night,  |
|davagatw@mars              Went home and put a bullet through his head.|
|              --Edwin Arlington Robinson         |
| -or- |