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WWYD with an input/output error when disk imaging optical media using dcfldd? Use ddrescue?

@elizabeengland FWIW I'd use ddrescue, which is my go-to tool for faulty CD-ROMs and DVDs these days. Also, dcfldd has some serious bugs and hasn't been updated since 2006, see forensicswiki.org/wiki/Dcfldd

@bitsgalore thanks! So is ddrescue the first tool you attempt imaging cdroms and dvds with?

@elizabeengland For bulk processing we developed a workflow that uses IsoBuster, more info here: openpreservation.org/blog/2017 We're not using that operationally yet, but a pilot will start later this year (1/2)

@elizabeengland (2/2) for discs that are damaged or otherwise problematic ddrescue often gives better results (at the cost of being more labourious). We currently only use this for discs that are particularly important/valuable. For example, we used it to recover a unique CD-ROM with the contents of the very first Dutch web index: openpreservation.org/blog/2018

@elizabeengland Also, the section "When read errors happen: try ddrescue" in this old blog post (blog.kbresearch.nl/2015/11/13/) explains how to run multiple consecutive ddrescue passes with different optical drives. This can work surprisingly well for discs that result in (limited amounts of) read errors

@bitsgalore thanks a ton, you (and your blog post) really helped me! ddrescue worked on the first attempt with this disc

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