Subject: Re: Another changer, another changer problem
To: NetBSD-current Discussion List <firstname.lastname@example.org>
From: Greg A. Woods <email@example.com>
Date: 10/03/1998 21:53:34
[ On Fri, October 2, 1998 at 23:51:28 (-0700), Curt Sampson wrote: ]
> Subject: Re: Another changer, another changer problem
> > It's one thing to have a "convention" where a
> > certain slice represents the entire physical device, but yet another
> > thing entirely to encode that convention into the driver.
> That's nothing to do with the driver. Please read the code.
The "convention" is "encoded" in the driver by the mere fact that the
driver forces you to use a partition that starts at cylinder zero, track
zero, sector zero in order to read the disk label.
To break this "convention" on would either have to add a new ioctl to
the driver such that the label can be read and written without having to
directly touch any physical disk sectors, *or* for the driver to always
provide a minor number by which the raw disk can be accessed from end to
end regardless of what's in the current label (either on disk or in core).
> I don't see where you need any kernel support for this. In fdisk,
> yes. In the kernel, why?
I think it would make things easier, more consistent, more orthogonal
and more elegan. Wnen I once used systems which did provide in-kernel
handling of the fdisk partitions things were *far* more logical and easy
to understand, and mistakes were impossible to make because everything
had to fit together and remain consistent.
> > I don't see where the "bloat" is though -- just one more table for the
> > driver to sort through before it sets up partition to physical mapping.
> There's more than just a table. There's a bit of code to deal with
> to. Code that's completely useless on any other system.
That code need not be included in any kernel that's running on sane
hardware that doesn't have a PC BIOS.
Greg A. Woods
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