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Date:      Thu, 22 Apr 1999 11:23:09 -0700 (PDT)
From:      Doug White <dwhite@resnet.uoregon.edu>
To:        cjclark@home.com
Cc:        danderso@crystalsugar.com, freebsd-questions@FreeBSD.ORG
Subject:   Re: Using Raw wd
Message-ID:  <Pine.BSF.4.03.9904221122260.7869-100000@resnet.uoregon.edu>
In-Reply-To: <199904220422.AAA14618@cc942873-a.ewndsr1.nj.home.com>

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On Thu, 22 Apr 1999, Crist J. Clark wrote:

> Doug White wrote,
> > A hard disk has variable geometry and partition information in the
> > disklabel that is specific to the disk & slice.  You'd have to regenerate
> > the disklabel as you were writing the chunk.  The ?d driver does not do
> > the fixups necessary for this access mode to work correctly.
> 
> Why can I do this with a SCSI disk, which in some sense, has an even
> more 'variable geometry?' I've read/written to Jaz drives (/dev/sd0)
> as raw devices with no ill effects. Isn't one of the most powerful
> aspects of UNIX flavored operating systems that devices are in some
> sense treated just like files? Or that most operations are transparent
> with respect to the hardware underneath? It'd be nice to be able to,
> 
> $ tar cf /dev/st0 something/
> $ tar cf /dev/fd0 something/
> $ tar cf /dev/sd0 something/
> $ tar cf /dev/wd0s4 something/

Don't use block devices, use /dev/r*.  You may have better luck.

> > In sum: don't do that :)
> 
> *sigh*
> 
> I've checked the disklabel on the slice and given /dev/wd0s4c a shot
> to and more Very Bad Things. I guess I'll have to put a filesystem on
> the partition.

Have fun.

Doug White                               
Internet:  dwhite@resnet.uoregon.edu    | FreeBSD: The Power to Serve
http://gladstone.uoregon.edu/~dwhite    | www.freebsd.org



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