OT: Can Reformatting A Hard Drive To ext3 Destroy All the Data On It?

Robert L Cochran cochranb at speakeasy.net
Wed Jun 3 01:52:01 UTC 2009

On 05/29/2009 09:46 PM, Robert L Cochran wrote:
> On 05/29/2009 05:44 PM, Alan Cox wrote:
>>> 'shred' is part of coreutils (i.e. installed by default).
>>> Doing something like
>>> shred /dev/sdX
>>> as root will write various bit patterns 25 times over the entire drive
>>> (see the man page for more options).
>> Whoopeeedoo. Thats still not the correct way to erase a disk.
>> Use security erase, that is why it is there.
> Thanks very much to all who responded! I'm going to use Alan's 
> suggestion first of all and if necessary a mixture of everyone else's. 
> For good measure maybe I'll dump a pound or so of salt in a gallon of 
> nice hot water and drop the hard drive in and wait for signs of rust 
> to appear. Ha ha!
> Thanks again!
> Bob

I bet you all want to know what I did to the hard drive. Well, maybe you 
don't. First off, I tried to find out of the drive has a secure erase 

# hdparm -I /dev/sdb

HDIO_DRIVE_CMD(identify) failed: Invalid exchange
# hdparm -i /dev/sdb

HDIO_GET_IDENTITY failed: Invalid argument

[It does not seem to have a secure erase feature.]

[So I did this:]

# dd if=/dev/zero of=/dev/sdb bs=1M
dd: writing `/dev/sdb': No space left on device
28630+0 records in
28629+0 records out
30020272128 bytes (30 GB) copied, 1579.48 s, 19.0 MB/s

...and tomorrow, I will remove the circuit board from the drive, and if 
time allows, try out the brine-and-cola treatment. Or perhaps I'll 
disassemble the drive into parts for my own education.

Thanks everyone!


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