Bits, bytes, mb, gb,tb,zb

1 Exabyte = 1,152,921,504,606,846,976 Bytes
= 1125899906842624 KBytes
= 1099511627776 MBytes
= 1073741824 GBytes
= 1048576 TBytes
= 1024 PetaBytes
= 1 Exabyte

Zettabyte ~ 1 000 000 000 000 000 000 000 bytes
Yottabyte ~ 1 000 000 000 000 000 000 000 000 bytes



And the reasons for the names :
Kilo Greek khilioi = 1000
Mega Greek megas = great, e.g., Alexandros Megos
Giga Latin gigas = giant
Tera Greek teras = monster
Peta Greek pente = five, fifth prefix, peNta - N = peta
Exa Greek hex = six, sixth prefix, Hexa - H = exa
Remember, in standard French, the initial H is silent, so they would pronounce Hexa as Exa.
Zetta almost homonymic with Greek Zeta, but last letter of the Latin alphabet
Yotta almost homonymic with Greek iota, but penultimate letter of the Latin alphabet.

http://en.wikipedia.org/wiki/Zettabyte