dd problem

[charlie derr]

Pedantically correcting myself.  First off I was responding directly to Karl F. Larsen (which makes it pretty ironic 
that I started out complaining about Karl's quoting error when my mailer ended up not doing it write either :-\)


charlie derr wrote:
>> charlie derr wrote:
>>> Karl F. Larsen wrote:
>>>> Georg von Zengen wrote:
>>>>> so you have to delete it, chose another name or creating a new file in
>>>>> "nita". dd can only write into files e.g.
>>>>> sudo dd if=/dev/sdb1 of=/media/disk/nita/sdb1 bs=2048 conv=notrunc
> 
> OK, first problem, you appear to have quoted me, but you've snipped out
> all of what I typed (and a lot of other important stuff).  For instance
> what you typed.  Which is that you didn't believe that command was going
> to work.  So why respond to it this way?  Sorry but it's hard to
> communicate with you no matter how hard I want to succeed at it.
> 
>> 	Now a couple of what happened problems. Again this is on
>> Ubuntu 9.04 using a 160 GB portable HD in a box made by ADS
>> Tecnologies, China.
>>
>> 	My first question is: Why does dd ruin a file system when it
>> is directed to put some files on the HD?
> 
> Because you ignored the advice above and fumbled around trying things
> instead.  If you'd actually executed the command Georg suggested (at the
> time Georg suggested) it would have worked as expected.
> 
>> The HD had ext3 file
>> system and it was shown as /media/disk then. Then I used dd to
>> get as much as possible from a bad HD and put it on the
>> portable HD. It did but it ruined my portable system! Now when
>> plugged into this computer it showed as /media/CEE.
>>
> 
> It's all about you gaining an understanding of the difference between
> partitions and filesystems and how things that live at /dev can be either
> (it's up to the intelligence and knowledge of the user to distinguish
> sometimes).

This is the part I wanted to make sure I corrected.  What I wanted to say was "the difference between disks and 
partitions"  (not partitions and filesystems)  The error Karl was not understanding that when you thought you were 
writing to a file on a particular partition, you were instead writing your image to *the entire portable harddrive* 
(because that's what you told dd to do).



> 
>> 	After getting the stuff on another computer I tried to fix
>> the portable. I tried to remove CEE. I did remove most of it
>> but not all. Took the HD out of the portable and onto this
>> computer. Here I used Partition Editor to see this HD. It said
>> the HD has a ntsf file system and no sign of any ext3.
> 
> This totally makes sense to me.  In the reply you snipped I already
> explained that you had made an exact copy of your computer.  Obviously
> that computer had an NTFS filesystem on it.  Now it's on your portable
> (and that's all that's on the portable because you told dd to overwrite
> everything else the way you executed your command.

This was only temporally accurate (in terms of my use of "Now..." ) until the below effort (wiping it clean again and 
replacing the NTFS filesystem with an ext3 one).

> 
>> To fix
>> this I had to delete the partition and then re-make a new ext3
>> file system.
>>
>> 	Another question. I backed up all of /home/karl which is now
>> about 25GB with dd. It worked fine and when complete I looked
>> at /media/disk and ls and ls-al both said there is nothing on
>> the portable HD!  I unmounted the portable and turned it off,
>> and then back on. Looked and sure enough the backup was on the
>> portable as I expected! Why didn't it show up right after dd
>> was complete?
> 
> I don't know the answer to that one.  Maybe someone else has a clue.
> 
>     be well,
>          ~c
> 
> 
>>
>> 73 Karl
>>

Sorry for the errors in what I posted quickly an hour or so ago.
      ~c



>>
>> --
>>
>> 	Karl F. Larsen, AKA K5DI
>> 	Linux User
>> 	#450462   http://counter.li.org.
>>          Key ID = 3951B48D
>>
>>
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> 
>