Disk imaging program?

Bill Stanley bstanle at wowway.com
Wed Jun 25 13:30:12 UTC 2014

On 06/25/2014 04:41 AM, Nils Kassube wrote:
> < snip >

> You asked for an application that preserves the boot sector, so you 
> obviously want something that does sector by sector copy. Therefore dd 
> seems to be a sensible choice to me. If you want to keep data only, I 
> would suggest to use tar, but then the boot sector is gone. 
> Furthermore there seems to be a little confusion of what tar does. It 
> is not a compression tool but an archive program which doesn't do 
> compression on its own. The suggested command "tar -czf" would invoke 
> gzip for compression but it wouldn't be useful together with dd IMHO 
> because using gzip alone would suffice.
>> And can you kindly confirm that dd knows how to prompt for the next
>> split?
> No, I don't think dd can prompt for a split. But I think tar could do
> that - have a look at the -F and -M options.
> Nils
WS=> Interesting discussion about compression...

      The thing that is VERY important to remember is that and 
compression scheme must be able to restore the boot sector EXACTLY!   
Most data files can tolerate a small bit of compression loss (although 
losses are undesirable).  As such, it would be best to handle the boot 
sector separatly and without compression that would assure that it 
doesn't get corrupted.  As for the rest of the stuff, use compression 
but use it only as much as needed.

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