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Date:      Fri, 5 Dec 1997 14:26:29 -0800 (PST)
From:      Julian Elischer <julian@whistle.com>
To:        "Ron G. Minnich" <rminnich@Sarnoff.COM>
Cc:        hackers@FreeBSD.ORG
Subject:   Re: a strange problem with slices, 3.0-current, and disks
Message-ID:  <Pine.BSF.3.95.971205141732.15892E-100000@current1.whistle.com>
In-Reply-To: <Pine.SUN.3.91.971205093353.14108A-100000@terra>

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On Fri, 5 Dec 1997, Ron G. Minnich wrote:

> For example, what doesn't work is the following:
> dd if=/dev/zero of=/dev/rwd0 bs=512 count=128. 
> dd reports one block in, zero out. 
> The kernel prints three messages of the form:
> wd0s1: type 0x6, start 63, end=4193279, size=4193217: OK
> wd0s2: ....  different start and end and size: OK
> wd0s5: ...  different start and end and size: OK
so dd is not writing to the device.

try:
fdisk -iu /dev/rwd0
and enter 0 for every possible numerical field

then: 
reboot
disklabel -w -r /dev/rwd0 floppy3
disklabel -e -r /dev/rwd0
[edit to taste]

reboot:

julian

> The kernel prints these messages every time I do anything to the disk. 
> (read, write, whatever). I also can not
> dd if=/dev/rwd0 | od -xc | more
> dd gets an immediate EOF! rwd0 is not functioning as it used to. 
maybe the drive has a 'virus protect feature'?

> 
> fdisk can't do anything with this disk either. What appears to be
> happening is that any reference to rwd0 is somehow being redirected to the
> 4th partition on the disk, which is the only unused one, and which is also
> zero bytes long: immediate error. 
> 
> I'm now very confused, and I hate to drop this on hackers, but: 
> 1) questions has resulted in only one (non-working) answer
> 2) This looks like a bug, or at least a big change in How Things Work
Out of curiosity:
If you have time..
get my 'slice' patches from:
ftp:hub.freebsd.org/pub/scsi/slice2.tar.gz
and apply them to a current kernel.
make a kernel with 
options DEVFS and SLICE (see the SLICE config file)
boot it single user.
mount -t devfs /devfs /mnt
cd mnt
then try smash the device as before.
that code is a lot more direct about getting at the device and bypasses
all the present BSD slice/partition confusion.

> 
> one more question: how does the install tool do it? how does the install 
> tool blast the dos partitions, where is the ezboot that it loads onto the 
> disk, and how does it get ezboot there? The install tool does not appear 
> to use fdisk/disklabel, or if it does, it's using them in a way I don't get.
no it uses libdisk whish is cool but not humanly usable
of course you COULD just run the install floppy.....

> 
> thanks
> ron
> 
> Ron Minnich                |Java: an operating-system-independent, 
> rminnich@sarnoff.com       |architecture-independent programming language
> (609)-734-3120             |for Windows/95 and Windows/NT on the Pentium
> ftp://ftp.sarnoff.com/pub/mnfs/www/docs/cluster.html 
> 
> 
> 




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