3 ms·

For me, support for archive recovery record, which 7zip does not support.

• davidcollantes 3y ago
  Because I didn’t know about this, and was curious to find out more: https://www.win-rar.com/recovery-record.html https://www.win-rar.com/recovery-record.html “Using Recovery Record slightly increases the size of your .rar files, but it helps to recover data should your file become corrupted by a virus, bad disc, etc. The larger recovery record allows you to restore a bigger damaged area, but increases the size of the archive and the process is slower."
  • jakub_g 3y ago
    I used this a lot in early 2000s when my only internet connection was at school or internet cafes, and the data transfer was via a bunch floppy disks I carried with me. The floppies often had issues, so a single corrupted byte would normally corrupt the downloaded files (especially images and binaries) but with 10% or 20% of recovery data written in a non-damaged place, it could manage to un-rar. If you're curious how this works: say you have some data like below: 10001100 11001010 11001010 01001010 10001100 11001010 11001010 01001010 You can calculate a sum of each row and each column, mod 2, and store it somewhere. When a single bit gets flipped, with the extra data (assuming the recovery data itself is not borked), you can calculate exactly which bit got flipped. (You can also calculate other kinds of extra data which can deal with more complex bit flips).
  • yjftsjthsd-h 3y ago
    So it's like appending a par2
• mmh0000 3y ago
  I seen this mentioned a few times in the thread. While true, there are other tools (with more control) for creating recovery data, notably, parchive[1]. [1] https://github.com/Parchive/par2cmdline https://github.com/Parchive/par2cmdline