When I used RAR, I had an option to add some extra recovery data in order to be able to cope with a not-perfect medium (think floppy disks). It saved my day several times, specially when dealing with old CDs (scratched or when the reflective layer was damaged with bubbles).
I also used Parchive to redistribute several CDs with a "parity" one in a manner not unlike RAID.
So, in the era of DVDs, external HDD and Flash storage :
- Is it still worth it ?
- Is it only available as a external package like Parchive or only with RAR since various better compression formats exists ?