[kwlug-disc] Backup a USB Flash Drive to DVD.

[Chris Frey]

To be absolutely sure you have the same image as a backup,
Cranky is correct about 'dd', and you likely want the whole device,
not just a partition.  Then just burn the file to a DVD.  This is the
easiest and most certain way to make a backup.   That way you know you
can just revert the USB quickly in case of disaster.

If you're lucky, the USB stick might have partitions (/dev/sdb1, etc),
and one of them might be formatted as an isohybrid.  In that case,
you may be able to peel /dev/sdb1 off the USB and burn the result
as the ISO.  I haven't burned CD/DVDs in a while, so I don't know
if this is will work.

Some interesting links I found while poking at this problem:

	https://unix.stackexchange.com/questions/403463/how-to-make-a-bootable-iso-file
	https://wiki.syslinux.org/wiki/index.php?title=Isohybrid
	https://en.wikipedia.org/wiki/ISO_9660

- Chris


On Wed, Jul 14, 2021 at 08:21:54AM -0400, CrankyOldBugger wrote:
> I was going to say that "dd" is your best bet, but to be honest I've never
> done this in Linux with a CD, so caveat emptor, you should read up on "dd"
> before you start.  You'll need to read up on the command line parameters as
> well.
> 
> I do use "dd" to copy ISOs to USB, or ISOs to SD cards all the time, so I
> know it works well there.  But I've never used it with CDs.
> 
> 
> On Tue, 13 Jul 2021 at 21:47, John Driezen <jdriezen at sympatico.ca> wrote:
> 
> > I recently purchased the latest version of Eurosoft's PC Check. The
> > software came on two 8 GB USB thumb drives.  I would like to know how to
> > back the contents of the thumb drives up, preferably to a bootable
> > CDROM, which I can not accidently overwrite, as PC Check contains
> > options to destructively erase hard drives.
> >
> > The output of df -hT shows this:
> >
> > Filesystem     Type      Size  Used Avail Use% Mounted on
> > /dev/sdh1      vfat      6.5G   63M  6.5G   1% /media/john/EUROSOFT
> >
> > As you can see, the thumb drive is mostly blank and the files will
> > easily fit on a CDR.  PC Check boots to EURODOS, and runs PC Check from
> > there.
> >
> > I know I can use mkisofs to create an iso file containing all the files
> > from the mountpoint /media/john/EUROSOFT, and then write that iso file
> > to a CDR or DVD-R.  How can I make said CDR or DVD-R bootable?  I did
> > read the man page for mkisofs, but find all the options confusing.
> >
> > John Driezen
> >
> > jdriezen at sympatico.ca
> >
> >
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> >

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