bcwipe won't wipe a block device...

[Aaron Peterson]

> On Thu, Feb 19, 2004 at 12:57:52PM -0500, Aaron Peterson wrote:
>> I don't know if this is a problem specific to CURRENT or not, but bcwipe
>> seems to do the right thing when wiping files.  however, when using the
>> -b
>> option to wipe an entire block device, there is an "Invalid Argument"
>> error, and I don't understand exactly why...
>>
>> fbsd52# bcwipe -bvmd /dev/da0
>> Wipe /dev/da0 (y/[n]/a)?a
>> Wiping device      /dev/da0
>> Writing to /dev/da0: Invalid argument
>> fbsd52# bcwipe -bvm3 /dev/fd0
>> Wipe /dev/fd0 (y/[n]/a)?a
>> Wiping device      /dev/fd0
>> Writing to /dev/fd0: Invalid argument
>> fbsd52#

> Why - if the device is there you have a node in /dev.
> If you don't have the device then there is no node.
> See devfs(8)

I understand how devfs works, and i don't think that is the problem,
although perhaps I'm misunderstanding what you mean.

dd if=/dev/urandom of=/dev/da0
dd if=/dev/urandom of=/dev/fd0

these devices and nodes all exist, and these dd commands do as expected
and take off writing random data to the raw device.  However i get the
errors mentioned previously when i try to use bcwipe on the same drives. 
I would like to find a way to make bcwipe work.  any suggestions about
what is causing this problem?