Xen list at
Sun Dec 3 08:19:59 UTC 2017

Ralf Mardorf schreef op 03-12-2017 8:36:
> On Sun, 03 Dec 2017 08:25:41 +0100, Xen wrote:
>> dd
> Apart from myths about forensics, let's assume that overwriting data
> one time is secure, but you still can't compare overwriting a whole HDD
> using dd and shredding files on a partition of a HDD using the shred
> command. There's something maintaining the available free HDD space,
> e.g. to ensure a good performance. Again, we don't need to defragment
> HDDs, it's an automated process were data is moved and copied.

Actually this is incorrect.

In 2009 there was work on a kernel patch that would allow a defrag 

Apparently, it was never completed.

Ext4fs does NOT automatically defragment files, unless I am mistaken 

It intelligently pre-allocates files, but it does not defragment after 
the fact.

So there is no data being moved and copied (except by userspace 

Of course user space programs can still leave temporary copies on disk.

For which "sfill" is needed.

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