1) Unit of information 
The yottabyte is a multiple of the unit byte for digital information. The prefix yotta indicates multiplication by the eighth power of 1000 or 1024 in the International System of Units (SI), and therefore one yottabyte is one septillion (one long scale quadrillion) bytes. The unit symbol for the yottabyte is YB. A related unit, the yobibyte (YiB),...
Unit of storage, details ...