* Carlos E. R. <robin.listas@telefonica.net> [01-14-18 04:29]:
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On Friday, 2018-01-12 at 20:27 -0500, Anton Aylward wrote:
...
Forgot to comment on this.
Once you do get into spanning multiple DVDs then you get into two issues. The decision of where to split goes hand-in-hand with the decision of what files to put on each DVD most efficiently (or optimally) -- the 'packing problem' which is at the very least NP-hard and quite probably NP-complete https://en.wikipedia.org/wiki/Bin_packing_problem https://en.wikipedia.org/wiki/Knapsack_problem#Multiple_knapsack_problem https://en.wikipedia.org/wiki/Packing_problems
With real backup software this is not an issue at all. Files are stored one after the other on the medium, and the last one is split at the byte that doesn't fit, without mercy, and continues the following byte on the next DVD. Plain as that. Finally, there is an index that says in which DVD is each single file, and that index is stored in the last DVD, and in the hard disk. Or the other way round, first in the HD, then in the last DVD. This might be a problem if it takes a bit to calculate while the disk is burned on the fly - or not.
The second issue is that you need a global index of what is on each DVD. Either you have to pre-compute the "bin packing" and ahead of time and record the index on each DVD as a 'header' that says 'it's here or its on the other one' or the index has to be external.
See above.
I can't say I like any of this.
What we need is a K3B that is super-super smart, since I really don't fancy trying to all this with shell script.
Things can be improved if the slices contain compressed data, plus extra recovery data to protect from read errors in the future.
All I described is what PCtools backup did back in 1980, but with floppies. Nothing new.
No, I have not found software that does this in Linux. Yet, I hope.
pretty certain dar, disk archiver, will do that, except it does not do the write to cd/dvd/bluray -- (paka)Patrick Shanahan Plainfield, Indiana, USA @ptilopteri http://en.opensuse.org openSUSE Community Member facebook/ptilopteri Registered Linux User #207535 @ http://linuxcounter.net Photos: http://wahoo.no-ip.org/piwigo paka @ IRCnet freenode -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org