Re: Erasing DASD-decommission an AS400/iSeries/System i

[Vernon Hamberg <vhamberg@xxxxxxxxxxx>]

Just to be cantankerous - a physical file has a bunch of overhead 
stuff that will never be touched by this process - every data space 
has a segment header, etc. Even stuff in the IFS contains this stuff 
- so there'd be SOMEthing always left over that is not wiped.

I think!

Heh!

At 07:57 PM 1/18/2007, you wrote:

> To be even more effective you need to write more bit patterns:
>
>         01010101
>         10101010
>
> And just for fun:
>
>         00110011
>         11001100
>
> etc. etc.   I think the DOD requirements include bit patterns and a
> number of over-writes.  Or a sledge hammer or drill!
>
> As I understand the problem with erasing disks, it's the thermal
> expansion and contraction that causes incomplete erasure of the edges
> of the tracks-- because the heads aren't perfectly aligned with the
> track.  And those 'fringes' are the bits   (:  that can be read under
> extremely special circumstances.
>
> So maybe you need to chill the computer room to near-freezing, run
> the program, then let it creep up to 100 degrees or so and repeat,
> just to get the fringes!
>
> In any event:
>
>         Write
>         etirW
>         repeat
>
> --Paul E Musselman
> PaulMmn@xxxxxxxxxxxxxxxxxxxx
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