Re: The dd imaging utility Question NO Bug Report

[Bob Proulx]

> First a little explanation so things might be clearer. We are a fairly small
> company and we do not have any programmers. :-((. What we want to do is make
> some sort of restore CD like the CD's from HP and Compaq etc.

First I wanted to say that I have never liked the restore CD's from
either of those two vendors, now the one vendor if the merger is
approved.  They are terribly inconvenient.

For a real example, I have partitioned my Compaq 1621 laptop disk
drive to dual boot GNU/Linux and MS-Windows.  The laptop contains
hardware which requires proprietary drivers for Windows.  [Linux
actually handles things acceptably.]  Compaq does not make available
the Windows drivers outside of the restore image.  [Actually they
recently think they do, but the individual drivers won't load
properly.  It is missing some magic.]  But let's not dwell on this, it
is only to set the stage.

When it becomes necessary to reinstall Windows on the box things are
very difficult.  Because the restore CD is an image only restore I
cannot restore to the windows partition.  I must back up my Linux
partition, restore the entire windows partition since that is the only
option which destroys the GNU/Linux partition, then shrink it with
fips to make a new linux partition, and then finally restore the Linux
partition.

Things are a even worse now.  I upgraded to a bigger disk drive.  But
the image only works with the exact size drive as before.  Which means
I need to disassemble my laptop and swap the old drive back into
place, then restore, then backup windows using a different process
unique to my setup, then swap disk drives again and finally restore
from backup the windows partition onto the new drive.  Whew!

That is more work than most people want to do.  I have no knowledge of
your application but I recommend you find some method to restore the
files and not the disk image.  Restoring a disk image is very
inflexible.

What if you decide to change to a different size disk drive?  That
would seem a common change but in that case you would need a different
restore image.

> Now they have their own utilities, we were thinking about ghost, but
> the licenses are too expensive for this kind of usage. Now I make
> images from floppies on my linux which I then can set back using dd
> if=<floppy image file> of=/dev/fd0u1440. We were thinking we could
> make a bootable CD which has an autoexec.bat which does sortta the

If you are booting and using the autoexec.bat you must be booting in a
DOS mode and I am guessing thinking of using the Cygwin utilities from
http://www.cygwin.com/?  You could also boot linux and use the native
GNU utilities.

> same but then with harddisk images and the dd utility. However there
> is 1 problem with dd that I cannot overcome.  It makes great images,
> however there are as big as the harddisk.

:-)  That is it's job.  Glad to hear it is working properly.  :-)

> Now a clean Windows 98/ME/2000 installation takes about 200MB give
> or take several MB's, however dd images the harddisk
> entirely. Having a 20GB harddisk for instance this would never fit
> on a CD. So the quesion is, is there a variant of dd or can dd
> either compress the empty space, which should result in like
> 10kBytes for 19,8GB empty space so we can burn the image on CD and
> then use the DOS dd utility from a bootable CD to set the image
> back. Now that I think of it, maybe there's a possibility we can
> direct the image through gzip so we won't ever need the diskspace
> for the fullimage but it gets comprimised in memory and do the same
> for setting it back? We are allowed to use dd in this way right?

If you do not specify the od=FILE option then the output will be to
standard output, which may be piped to gzip and the output redirected
to a file.  On UNIX systems this will multitask between the two
process.  On DOS systems (thinking that you might use cygwin on dos) I
think, not too familiar with them, that pipes are simulated using
temporary files.  Which probably would not work for you.  But on a
UNIX system you can pipe them together.

  dd if=/dev/... | gzip > fileimage

> Aslong as we keep the disclaimers n stuff right?  (I'm not native
> english and I don't understand a whole lot of laws).

Your english reads better than many native speakers.  No apologies
needed.

Bob