Bytes in Perspective

Below is the sequence of names for describing digital information - Think of a byte as a letter or number, such as 1 or T.  A kilobyte is exactly1,024 bytes, but common usage rounds it to a thousand. One page of text is about one kilobyte.

Here are some more comparisons to give you a sense of scale - A terabyte is roughly a trillion bytes and our national debt is measured in trillions of dollars. One terabyte can hold about 3.6 million images or about 300 hours of good quality video. A terabyte can hold 1,000 copies of the Encyclopedia Britannica. Ten terabytes can hold the total printed collection of the Library of Congress. We are adding about a terabyte of information to the internet roughly every minute of every day.

kilobyte (kB)     10³
megabyte (MB) 10⁶
gigabyte (GB)   10⁹
terabyte (TB)    10¹²
petabyte (PB)   10¹⁵
exabyte (EB)     10¹⁸
zettabyte (ZB)   10²¹     
yottabyte           10²⁴

There are more names going up to ten to the 63rd power, but only those above have so far been approved. I have a friend who is so old, he remembers plain old bytes, now we have moved from Kilobytes to Exabytes. Hope to be around for the Yottabyte revolution.

Gigabytes, Terabytes, and Petabytes

One gigabyte of storage cost $228 in 1998 and costs about 88 cents today. A gigabyte holds about 7 minutes of a HD TV movie.

A terabyte is 1,024 gigabytes. The first terabyte hard drive came out in 2007. In May 2009, Yahoo! Groups had 40 terabytes of data to index.

There is an even larger scale these days, petabytes. One petabyte is 1,024 terabytes. A petabyte holds 13.3 years of HD TV movies. To provide more perspective, Google processes an average of about 20 petabytes of data per day. Finally, 50 petabytes is equal to the entire written history of mankind from the beginning of recorded history. What's next? An exabyte is 1024 petabytes.