Kilo-

Kilo (from the Greek χίλιοι, literally a thousand) is a decimal unit prefix in the metric system denoting multiplication by one thousand (10³). It has been used in the International System of Units where it has the unit symbol k, in lower case.

The prefix kilo is derived from the Greek word χίλιοι (chilioi), meaning "thousand". It was originally adopted by Antoine Lavoisier's research group in 1795, and introduced into the metric system in France with its establishment in 1799. Based on a proposal by Thomas Young, the prefix was often alternatively spelled chilio- in early 19th century sources.

Examples:

A second definition has been in common use in some fields of computer science and information technology, which is, however, inconsistent with the SI definition. It uses kilo as meaning 2¹⁰ = 1024, because of the mathematical coincidence that 2¹⁰ is approximately 10³. The reason for this application is that binary values natively used in computing are base 2 and not the base 10 which is used for the SI prefixes. The NIST comments on this confusion: "Faced with this reality, the IEEE Standards Board decided that IEEE standards will use the conventional, internationally adopted, definitions of the SI prefixes", instead of kilo for 1024.

Kilo

Kilo may refer to:

See also

Binary prefix

A binary prefix is a prefix attached before a unit symbol to multiply it by a power of 2. In computing, such a prefix is seen in combination with a unit of information (bit, byte, etc.), to indicate a power of 1024.

The computer industry has historically used the units kilobyte, megabyte, and gigabyte, and the corresponding symbols KB, MB, and GB, in at least two slightly different measurement systems. In citations of main memory (RAM) capacity, gigabyte customarily means 7009107374182400000♠1073741824 bytes. As this is the third power of 1024, and 1024 is a power of two (2¹⁰), this usage is referred to as a binary prefix.

In most other contexts, the industry uses the multipliers kilo, mega, giga, etc., in a manner consistent with their meaning in the International System of Units (SI), namely as powers of 1000. For example, a 500 gigabyte hard disk holds 7011500000000000000♠500000000000 bytes, and a 100-megabit-per-second Ethernet connection transfers data at 7008100000000000000♠100000000 bit/s. In contrast with the binary prefix usage, this use is described as a decimal prefix, as 1000 is a power of 10 (10³).