That's a fantastic introduction (although it's far more than an introduction!). I wrote a native addon for Node.js that does Reed Solomon, also using optimized Cauchy matrices (MIT license): https://github.com/ronomon/reed-solomon
Very nice! I think I stumbled on your implementation when researching my post. :)
Thanks. If that was in November last year, then it's changed a lot since then (and now a few times faster). Back then it was using a Vandermonde matrix as it was based on Backblaze's Java implementation, but a month ago everything was rewritten to use optimized Cauchy matrices.