On Wed, Sep 2, 2009 at 5:32 PM, Dean S. Messing <deanm@sharplabs.com> wrote:
I have a terebyte sata drive that I need to securely wipe clean.  It
originally had 2 partitions.  I deleted them using `fdisk', rebooted,
and then as root ran

   shred -vz /dev/sdd

The drive is capable of about 60MB/sec, but shred is only "shredding"
about 25MB every 5 seconds according to its output.  Since the default
number of passes is 25, this works out to about 5 days.

The `shred' process is running at 100% CPU, presumably computing
the special random patterns for erasure.  Since I have 4 CPUs
would creating 4 unformatted partions on the drive and then running
something like:

  shred -vz /dev/sdd1
  shred -vz /dev/sdd2
  shred -vz /dev/sdd3
  shred -vz /dev/sdd4

in parallel cut my time?  Would be just as secure?

Thanks
Dean

Since when is formatting a CPU-intensive task?.

Think about this... the heads ALL move in parallel on the same platter.
There arenīt 4 individual head actuator arms moving heads independently. If the īarmī goes to track 255, all heads go to track 255...

Here, news for you:
http://www.dansdata.com/images/io012/heads1280.jpg

FC

PS:  this is also interesting reading....

Dual actuator HDs....
http://www.tomshardware.com/news/seagate-hdd-harddrive,8279.html