X · Coding theory
Reed-Solomon codes
What it is
Treat data as polynomial coefficients; transmit polynomial values at extra points. Recover from any t lost values with 2t redundant points.
Where it lives
CDs, DVDs, QR codes, Blu-ray, satellite communication, RAID-6, distributed storage erasure coding.
The key insight
A (255, 223) Reed-Solomon code corrects 16 byte errors per 255-byte block. The math behind every "scratched disc still plays" scenario.