Disc Reading

[Deleted member 169154]

This is a curiosity question.

Most disc (CDs, DVDs, BRs, etc) have some smudges or scratches. Obviously they can get scratched beyond the ability to read, but most of the time they are still fine with a decent amount of damage.

How is the laser not reflected / misdirected even with the slightest scratch? It just seems like it would have data corruption when even a tiny obstruction is in its way.

Basically, wondering how the technology has evolved past the imperfections to get reliable disc reading under bad circumstances. I first wondered if it was data redundancy, but rejected that because obviously they want to maximize storage based on the frequency of the laser.

 

[Menelmarar]

CRC and other forms of error detection and correction and help get around a lot of it.

Other than that, it's a laser, you ever use a pin laser and shine it through campfire smoke, or fog? Yes there are distortions, but the beam penetrates.