[omribahumi]

This means CDs should have ~800MB of usable space. Why only 700MB?

    705600 * 2 = 1411200              # bits/s for stereo channel
    80 * 60 = 4800                    # seconds in 80 minutes
    1411200 * 4800 = 6773760000       # bits in a 80 minutes CD
    6773760000 / 8 / 1024 /1024 = 807 # In MB

[dagw]

Error correction.

While a 'raw' redbook CD can hold ~850 MB, it is standard to included error correction codes so that a slightly scratched CD can still work.