1) One of the things that it took me a while to figure
out (although I confess to not having read the docs in
depth) is the efficiency value. Mostly because I
didn't figure out that files are boundary-aligned, so
it's a bad idea to have block sizes that are
drastically larger then your average file size.
I think it might be helpful if, when I click on the
"create" button that QuickPar would toss a warning
message (Yes/No/Help) if the efficiency value is going
to be less then 75%. Something to the effect of:
"Warning: You have chosen to create a recovery data set
with a large amount of wasted space. You may wish to
use a smaller block size to reduce this wasted space
and make your recovery set more space efficient." The
user should still be allowed to say "Yep, I'm sure" and
create the set anyway.
A refinement might be to allow the user to set their
pain threshold in the Options dialog (e.g. "Warn me if
wasted space is greater then 25%"), which would double
as a way to turn off the warning.
2) Warn the user if they are creating too many blocks.
I think the heuristic might be that you should
generally not have more then (number_of_files x 10)
blocks in a set. So for a 100 file set, there
shouldn't be more then 1000 blocks.
This might help with the slowness complaints because of
people creating PAR2 sets that take forever on the
destination machines due to large block counts.
Refinement would be to allow an option to tune this
setting... "Warn me if the recovery set has more then X
blocks per file."