Yes, ICKDSF can erase volumes, but I don't think IBM guarantees that it is a 
secure erase function. There might be situation where residual data is still 
readable. 

-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf 
Of R.S.
Sent: Wednesday, December 12, 2012 5:25 PM
To: [email protected]
Subject: Re: dsf to write over entire volume

W dniu 2012-12-12 18:04, Don Williams pisze:
> ICKDSF is not intended to erase volumes.
But it can erase the volumes, can't it?

> Now days, DASD volumes tend to be "virtual".

Virtual volume still contain real data. Excluding passing away "structured log 
file" technology (RVA, SVA), when you erase the logical
(virtual) volume, you overwrite the real data.

> Only the DASD controller may know on which real hard drives your 
> logical volumes are actually located and spread across.

Not only controller. Sometimes smart folks also know that. I'm not so smart, 
but I can tell you what is the relationship between physical discs and logical 
volumes in my array. I have it documented, and it can be checked/confirmed.


> To be sure that your data is actually erased, you may need to consult 
> with the vendor or other expert of your particular type of DASD.

It need not to be an expert. Last but not least: when you are going to dispose 
whole array, the choice is obvious: erase all logical volumes, isn't it?

> If the DASD is encrypted, you may be able to "erase" the encryption keys 
> making the DASD effectively unreadable.
Good assumption, unfortunately bad implementation. There are errors in "secure 
erase" implementation, at least for some disks, AFAIK. There nothing worse than 
false certainty in such area.

My €0.02
--
Radoslaw Skorupka
Lodz, Poland






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