What is a petabyte?
The new term that puzzled me last week was "petascale computing." Basically, this means very large capacity computing and comes from petabyte. So what is a petabyte? A petabyte is measure of storage space equal to 2 raised to the 50th power (1,125,899,906,842,624 bytes). This is still mysterious, so I did some research. Starting at the beginning, a "bit" a unit of measurement of information (from binary + digit) and is either a one or a zero. A byte is 8 bits. A kilobyte (or 1 KB) represents 1,024 bytes. A megabyte (1 MB) represents 1,024 KB. A gigabyte represents 1,024 MB. A terabyte is 1,024 gigabytes. A petabyte is 1,024 terabytes.
In the late 1980s, the average home computer system had a single hard drive with a capacity of about 20 megabytes (MB).
In 1997, Michael Lesk wrote, "How Much Information Is There in the World? (http://www.lesk.com/mlesk/ksg97/ksg.html). At that time, he said that the total size of the Library of Congress was about 3 petabytes.
His calculations were based on:
-- 20 million books, each requiring 1 MB
-- 13 million photographs, even if compressed to a 1 MB JPG each, would be 13 terabytes.
-- 4 million maps in the Geography Division might scan to 200 TB.
-- Over 500,000 movies; at 1 GB each they would be 500 terabytes (most are not full-length color features).
-- 3.5 million sound recordings, which at one audio CD each, would be almost 2,000 TB.
Thomas Landauer suggested that the brain holds about 200 megabytes of information, taking into account the rate at which information is forgotten and the amount of information need to do normal activities.
For more information, read: (This article is available electronically. Use Citation Linker.)
Thomas K. Landauer: How Much do People Remember? Some Estimates of the Quantity of Learned Information in Long-Term Memory. Cognitive Science. 10(4): 477-493 (1986)
The Libraries new Netfiles "U" drive has the capacity for 600 gigabytes.This is the new system that Libraries staff is now using to store and organize our internal electronic documents.
-- Peggy Johnson, Associate University Librarian

