[Debburn-devel] mkisofs/genisoimage and md5sum

Steve McIntyre steve at einval.com
Mon Jun 16 12:36:21 UTC 2008

On Mon, Jun 16, 2008 at 08:28:15AM -0400, jieryn at gmail.com wrote:
>On Mon, Jun 16, 2008 at 3:02 AM, Thomas Schmitt <scdbackup at gmx.net> wrote:
>> In my backup tool scdbackup there is a pipeline for this purpose:
>>  formatter | checksummer | writer
>That really wasn't very helpful, but thank you Thomas. I've solved
>this problem and am posting the solution here in case anyone else is
>jieryn at indigo$ mkisofs -quiet -o - directory | tee directory.iso |
>md5sum > directory.md5
>I've tested this on a variety of plain directory file trees as well as
>with the -dvd-video option and everything seems to be working swell.
>:-) I don't get status updates, but that's a penalty I'm willing to
>live with for not having to read ~8G two times.
>Developers, please consider adding md5summing directly as I do like
>the mkisofs status information appearing, it's quite handy.


We already have support inside genisoimage for calculating md5 and
sha1 checksums while data is passing through. I added it as part of
the support for generating jigdo files, but it's not (yet!) exposed in
a more generic way. It would be very easy to add, but what kind of
output would you find useful? Output to an extra file foo.md5sum
alongside foo.iso? Printed to the terminal at the end of the
genisoimage run?

We've also been asked by a Debian developer about adding support for
checksum files actually in the image itself, generated as other files
are added and appended right at the end of the run. I'm less happy to
add that (*very* complex in terms of edge conditions), but it might be
useful too.

Steve McIntyre, Cambridge, UK.                                steve at einval.com
  Getting a SCSI chain working is perfectly simple if you remember that there
  must be exactly three terminations: one on one end of the cable, one on the
  far end, and the goat, terminated over the SCSI chain with a silver-handled
  knife whilst burning *black* candles. --- Anthony DeBoer

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