Yottabyte

A yottabyte (derived from the SI prefix yotta-) is a unit of information or computer storage equal to one septillion (one long scale quadrillion or 1024) bytes. It is commonly abbreviated YB. As of 2009, no computer has yet achieved one yottabyte of storage. In fact, the combined space of all the computer hard drives in the world does not amount to even one zettabyte. According to one study, all the world's computers stored approximately 160 exabytes in 2006. As of 2009 the entire internet was estimated to contain close to 500 exabytes.
When used with byte multiples, the SI prefix indicates a power of 1,000:

• 1,000,000,000,000,000,000,000,000 bytes — 1000⁸, or 10²⁴

The term "yobibyte" (YiB), using a binary prefix, is used for the corresponding multiple of 1024