So perhaps another version of that table is, how much less par2 data is needed to achieve the same probability of success.
Actually, I've already done the computation, you you may be surprised at the answer. I certainly was.
Using the same 450 MB of data posted using a 500 KB article size (with 500 KB block size for PAR2, and 15 MB RAR/PAR files with PAR1), you get:
Recovery Article loss rate
failure rate 5 PAR1 files 5 PAR2 blocks
1 in 2 1 in 172 1 in 160
1 in 5 1 in 250 1 in 232
1 in 10 1 in 309 1 in 287
1 in 100 1 in 546 1 in 506
1 in 1,000 1 in 880 1 in 816
1 in 10,000 1 in 1364 1 in 1265
1 in 100,000 1 in 2037 1 in 1922
1 in 1,000,000 1 in 3111 1 in 2884
1 in 10,000,000 1 in 4633 1 in 4295
1 in 100,000,000 1 in 6867 1 in 6365
This means that to achieve a corresponding probability of succesfull repair you would need to post roughly 2.5 MB of PAR2 recovery data instead of 75 MB of PAR1 recovery data!
If this sounds incredible, then I'm not surprised.
Consider the same 450 MB of data and 500 KB article size, but this time there is only 1 x 15 MB PAR1 file and 1 x 0.5 MB PAR2 file:
Recovery Article loss rate
failure rate 1 PAR1 file 1 PAR1 block
1 in 2 1 in 546 1 in 537
1 in 5 1 in 1,110 1 in 1,093
1 in 10 1 in 1,721 1 in 1,694
1 in 100 1 in 6,159 1 in 6,062
1 in 1,000 1 in 20,152 1 in 19,835
1 in 10,000 1 in 64,384 1 in 63,378
1 in 100,000 1 in 204,272 1 in 201,059
1 in 1,000,000 1 in 646,639 1 in 636,469
1 in 10,000,000 1 in 2,045,353 1 in 2,013,183
1 in 100,000,000 1 in 6,468,907 1 in 6,367,162
In both cases, either no lost articles or one lost article is recoverable but two or more lost articles results in failure.
It should be obvious that in both cases the chances of losing two or more articles will be roughly the same (although with PAR 1 that is 2 articles spread across 930 and with PAR 2 it is 2 articles spread across 901), so the failure rate for a given article loss rate should also be roughly the same. The big difference is that the PAR1 file is 15MB and the PAR2 file is 0.5MB.
Peter, can you comment on whether a GUI version for Mac will become available?
This I do not know. However, since Mac OS X is based on unix, it aught to be able to compile and run the par2cmdline source code.