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So I got a DVD-RAM and a BD-RE both formatted with UDF, packet-writeable (I think packet writing is the wrong descriptor here as a DVD-RAM is randomly addressable but it's pretty close). At least the DVD-RAM seems to be somewhat offically supported and they are delivered with UDF on them as factory default anyway.

So now as I drag & drop a file onto the disc in Finder this will most of the time fail with some error like "xy cannot be read or written" same happens when using cp in Terminal to copy a file. i/o errors...

But this seems to happen only because some of the sectors are corrupted on the disc (and not yet marked as defective) or there are some buffering errors sometimes, because if you try often enough it will eventually write the whole file without an error. But especially with big files this is pretty annoying as the error occurs a little later every write until the whole file is written to disc (flawlessly btw. it reads and checksums perfectly then)

Is there anything I could try to fix this behavior? My best guess is Finder reacting too harsh to i/o errors as these are not very common for harddrives but much more common on optical drives.

BD-RE shows exactly the same issues but less often. DVD-RAM is worse by far.

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What is your Mac model? Since you mention BlueRay and DVD-RAM you must be using an external optical drive. Which maker/model? How is it connected to your Mac (USB, Firewire, ...)? Are you experiencing the problem with media from different manufacturers? – jaume Dec 21 '12 at 13:36
MacPro3,1 | Samsung SE-506AB/TSWD connected via USB | Yes the problem exists with different media types (RAM, BD) and different manufacturers of those (Verbatim (RAM+BD), TDK (BD)) – bardiir Dec 21 '12 at 19:07

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