An exabyte (EB) is a large unit of computer data storage, two to the sixtieth power bytes. The prefix exa means one billion billion, or one quintillion, which is a decimal term. Two to the sixtieth power is actually 1,152,921,504,606,846,976 bytes in decimal, or somewhat over a quintillion (or ten to the eighteenth power) bytes. It is common to say that an exabyte is approximately one quintillion bytes. In decimal terms, an exabyte is a billion gigabytes.
An exabyte of storage could contain 50,000 years' worth of DVD-quality video.