Securely delete files...

[David Shaw]

On Aug 22, 2008, at 2:38 PM, reynt0 wrote:

> On Thu, 21 Aug 2008, David Shaw wrote:
> . . .
>> whether the filesystem you are using overwrites in place or not.   
>> Many modern filesystems (Reiser, XFS) do not necessarily overwrite  
>> in place.  More primitive filesystems (like the FAT FS that is used  
>> on many external disks) do overwrite in place.  Linux systems most  
>> commonly use ext3, and that may or may not overwrite in place,  
>> depending on how it is configured.  Then there is the fact that  
>> many programs create temp files here and there which wouldn't get  
>> shredded.  On top of that there is the fact that many programs save  
>> files in ways that can defeat shredding.  Bottom line: it can be  
>> safe, but you have
> . . .
>
> Might anyone have any quick info about this issue for MacOS?
> From, say, OS10.2's HFS+, through OS10.3 and 10.4's journaled
> HFS+, to whatever the current OS10.5 does if different?

OS X is an interesting case.  The standard filesystem, as you note, is  
HFS+ with journaling.  Usually this is a danger sign for shredding as  
the shred process doesn't know all the information it needs to do a  
proper shredding job.  However, Apple has shredding built-in to OSX,  
and since both the shredder and the filesystem come from the same  
people, it's at least possible that they did the necessary work to  
have this shred properly (i.e. in a journal-sensitive way).  Did they  
actually do this?  I have no idea, and would be curious to hear from  
someone who does have a reference on this one way or the other.  Apple  
tends to be fairly stingy about this level of detail.

David