Because of irregularities in definition and usage of the kilobyte, the exact number could be any one of the following:
An exabyte is 1024 times a petabyte.
The San Diego Supercomputing Centre (SDSC) in the USA has a 1 petabyte hard disk store and a 6 petabyte robotic tape store, both attached to the National Science Foundations's TeraGrid network. [Source: Electronics Weekly, Dec 11, 2002]
To clarify the meaning (1) above, the International Electrotechnical Commission (IEC), a standards body, in 1998 defined new prefixes by combining the International System of Units (SI) prefixes with the word "binary" (see Binary prefix). Thus meaning (1) is called by the IEC a pebibyte (PiB), and meaning (2) is called by the IEC a petabyte. This naming convention has not, as of 2003, been widely adopted.