A ZettaByte is equivalent to 1024 ExaBytes, 1,048,576 PetaBytes, 1,073,741,824 TeraBytes, 1,099,511,627,776 GigaBytes, 1,125,899,906,842,624 MegaBytes , 1,152,921,504,606,846,976 KiloBytes, 1,180,591,620,717,411,303,424 Bytes or 9,444,732,965,739,290,427,392 Bits in the basic form of digital information storage, being composed of ‘0’s or ‘1’s in any combination.
On a CD or DVD the Bits are represented by ‘pits’ and ‘grounds’ (the normal flat metallic surface of the disc without any holes burnt or punched out of it) with a transition between a pit and ground being a 1 and a continuous spell within a pit or a ground being a 0.
On a tape or hard disc the same principle to a CD applies, but the pits and grooves are represented magnetically.
As a rough guide, you can fit 25 GigaBytes on a single-layer Blu-ray disc, 50 GigaBytes on a dual-layer Blu-ray disc, 4.7 GigaBytes of information on a full size (12cm) DVD and 0.7 GigaBytes of information on a standard (12cm) CD.
There are 8 Bits in a Byte, 1024 Bytes in a Kilobyte (KB), 1024 KiloBytes in a MegaByte (MB), 1024 MegaBytes in a GigaByte (GB), 1024 GigaBytes in a TeraByte (TB), 1024 TeraBytes in a PetaByte, 1024 PetaBytes in an ExaByte, 1024 ExaBytes in a ZettaByte and 1024 ZettaBytes in a YottaByte.