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Subject: Re: Unusual Question
From: Doug Hardie <bc979@lafn.org>
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Date: Fri, 14 Jul 2017 00:38:30 -0700
Cc: David Christensen <dpchrist@holgerdanske.com>,
 "freebsd-questions@freebsd.org Questions" <freebsd-questions@freebsd.org>
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To: Arthur Chance <freebsd@qeng-ho.org>
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> On 14 July 2017, at 00:26, Arthur Chance <freebsd@qeng-ho.org> wrote:
>=20
> On 14/07/2017 07:11, Doug Hardie wrote:
>>=20
>>> On 13 July 2017, at 21:44, David Christensen =
<dpchrist@holgerdanske.com> wrote:
>>>=20
>>> On 07/09/17 02:57, Doug Hardie wrote:
>>>> I have a FreeBSD 9.3 remote server that needs to be purged.  I know =
that rm -rf / will remove all the directory entries, but I need to write =
over the drive.  I thought that dd if=3D/dev/zero of=3D/dev/ada0 might =
do the trick, but it gives an not permitted error.  The whole thing can =
crash and burn at the end.  This is an unmanned site so moving drives is =
not viable.
>>>=20
>>> If the machine has BIOS and the system drive isn't too large, write =
an assembly program that fits into the MBR bootstrap code area to wipe =
the rest of the drive, assemble the program, write it into the MBR, and =
reboot.
>>>=20
>>>=20
>>> Bonus: the program deletes the MBR when done wiping the rest of the =
drive.
>>=20
>> Neat idea, but I have a number of these systems and they all use =
different disk drives.  That would be a lot of work writing drivers for =
each type.
>=20
> How about using the BIOS extended write sector call (INT 13h, AH=3D43h) =
in
> your code? That should be portable.

I have no experience with the BIOS so that sounds reasonable, but I =
couldn't say for sure.  Even so, that would be a bunch of work to figure =
all that out.  Great project for someone with time available.