Eckhard Kosin wrote:
The cp -rv showed up a file name with an unprintable character (the file originated from DOS, long time ago). Thanks. I renamed the file and now the system doesn't freeze, but the writer doesn't stop to write (more than 15 min for 293 MB ;-(. No hint from syslog, the only method to stop the writer is to switch it off and after a new switch on no data have been written to the DVD. It seems that UDF is rather unstable, at least in the AMD64 branch.
I guess as a 'universal disk format' for all operating systems, it is bound to be less feature rich than something tailored to linux. It was specifically developed with RW-media in mind and probably isn't at the top of fs performance for RAM-media.
I found that writing to RAM disks is much slower than writing to R/RW disks, assuming that it takes some extra time to verify the data (as far as I understand all data written to a DVD Ram are verified by the burner unlike in the case of R/RW). On my system it'll take about 20 minutes to finish writing the buffer, after my copy command is already back on the command line.
If, however, you experience a complete inability to write on UDF, I would consider filing a bug report - just to spare future users the time consuming 'experiments'.
Maybe you should try to write a small file structure first (say, about one MB) and try to expand from there.
Johannes