The article omits the really clever bit, namely the *Cross-interleaved" part of the error correction. What you effectively have is 2-dimensional parity checking, so that the error correction is very robust. In particular, it's robust against scratches.

Try an experiment:

Take an old (unwanted) CD, and either:

- scratch it severely with a sharp object

- draw 2mm thick radial lines on it in black marker.

It will still play perfectly.

[Confusingly, the *label* side is very vulnerable: it's very easy to destroy a CD with a screwdriver by attacking the labelled side, whereas the (apparently fragile) shiny side is almost impossible to destroy]

BTW, don't microwave CDs. Although the light-show is impressive, the smell of burnt plastic is *really* not nice!