Orders of magnitude (data)

An order of magnitude is a factor of ten. A quantity growing by four orders of magnitude implies it has grown by a factor of 10,000 or 104.

This article presents a list of multiples, sorted by orders of magnitude, for units of information measured in bits and bytes.

The byte is a common unit of measurement of information (kilobyte, kibibyte, megabyte, mebibyte, gigabyte, gibibyte, terabyte, tebibyte, etc.). For the purpose of this article, a byte is a group of 8 bits (octet), a nibble is a group of four bits. Historically, both assumptions have not always been true.

The decimal SI prefixes kilo, mega, giga, tera, etc., are powers of 103 = 1000. The binary prefixes kibi, mebi, gibi, tebi, etc. respectively refer to the corresponding power of 210 = 1024. In casual usage, when 1024 is a close enough approximation of 1000, the two corresponding prefixes are equivalent.

Note: this page mixes between two kinds of entropies: These two definitions are not entirely equivalent, see Entropy in thermodynamics and information theory.
 * 1) Entropy (information theory), such as the amount of information that can be stored in DNA
 * 2) Entropy (thermodynamics), such as entropy increase of 1 mole of water

For comparison, the Avogadro constant is $6.022$ entities per mole, based upon the number of atoms in 12 grams of carbon-12 isotope.

In 2012, some hard disks used ~984,573 atoms to store each bit. In January 2012, IBM researchers announced they compressed 1 bit in 12 atoms using antiferromagnetism and a scanning tunneling microscope with iron and copper atoms. This could mean a practical jump from a 1 TB disk to a 100 TB disk.