[rescue] Degaussing Drives?

[Stephen D. B. Wolthusen]

Hi,

On 26-Aug-2002 Bob Chu wrote:
> Hi,
> 
> Anyone out there know much about Degausing Hard Drives?
> The Story is:
> At my workplace, they need 30 or so Hard Drives low level formatted.
> They delegated this task to me, however his would take forever
> (considering I only work about 10 hours a week as a Student Worker, and 1
> available SCSI card for me to do the task)  While walking around in the
> Tech shop (Equipment/Electronics Maintenance) I bumped into an odd device,
> that the Technicians told me is a Degausser used back in the 80's to clean
> tapes (no one who is around now, actually seen it used) .  So I got the
> idea perhaps this will work on Hard Drives.  But
> before I begin, I just wanted to see if anyone knows anything about this
> kind of stuff.  Will this permantly damage hard drives (ie. screwing the
> motor up, Heads, etc).  How long do I need to leave a hard drive on it to
> make the data on the drive corrupted?  The degausser has all sorts of
> user put labels warning about fuse blowings after 4 mins of continuous
> use, etc, so I assume its pretty powerful?  The degausser is a Apex Model
> 111, Cat no. 13634-01 in case anyones intrested.

You don't degauss modern hard drives if you want to reuse them. Standard
procedure is to open the drive before degaussing (the aluminum casing
typically used doesn't matter) if you don't have a sufficiently powerful
degausser; the disks are very likely to be toast at any rate (since
you're erasing the factory-installed servo tracks; as far as I'm aware of no
modern drive has the ability to recreate, i.e. low-level format in the
traditional sense, these tracks). 

Degaussers, except heavy duty units, are not meant to operate continuously, so
that's perfectly normal. Duty cycles range from 1-5 minutes depending on the
degausser.

If you are in fact low-level formatting you should be aware of the fact that
media can be read after such a procedure, in most cases even after multiple
overwrites. 
.

-- 

        later,
        Stephen

Stephen Wolthusen (stephen at wolthusen.com)