According to these standards, kilo, mega, giga et seq. The symbols are the decimal symbol, always capitalised, followed by the letter "i". With the aim of avoiding ambiguity the International Electrotechnical Commission (IEC) adopted new binary prefixes in 1998 ( IEC 80000-13:2008 formerly subclauses 3.8 and 3.9 of IEC 60027-2:2005) Each binary prefix is formed from the first syllable of the decimal prefix with the similar value, and the syllable "bi".
#Giga hecta full#
To protect themselves, some sellers write out the full term as " 1 000 000". The ambiguity has led to some confusion and even of lawsuits from purchasers who were expecting 2 20 or 2 30 and considered themselves shortchanged by the seller. For example, a 500-gigabyte hard drive holds 500 billion bytes, and a 100-megabit-per-second Ethernet connection transfers data at 100 million bits per second. In the specifications of hard disk drive capacities and network transmission bit rates, on the other hand, decimal prefixes, consistent with the metric system, are used. For example, in citations of main memory or RAM capacity, kilobyte, megabyte and gigabyte customarily mean 1024 (2 10), 1 048 576 (2 20) and 1 073 741 824 (2 30) bytes respectively.
#Giga hecta series#
Computer professionals have historically used the same spelling, pronunciation and symbols for the binary series in the description of computer memory, although the symbol for kilo is often capitalised. Units of information are not covered in the International System of Units. This has prompted the use of the metric prefixes kilo, mega, and giga to also denote the powers of 1024 which is common in information technology with the unit of digital information, the byte. The tenth power of 2 (2 10) has the value 1024, which is close to 1000. Binary prefixes Prefixes for multiples of bits (bit) or bytes (B)Ī binary prefix indicates multiplication by a power of two.
The prefix " myrio-" was an alternative spelling variant for " myria-", as proposed by Thomas Young. The prefixes myria-, (from the Greek μύριοι, mýrioi), double- and demi-, denoting factors of 10 000, 2 and 1⁄ 2 respectively, were parts of the original metric system adopted in France in 1795, but they were not retained when the SI prefixes were agreed internationally by the 11th CGPM conference in 1960. Some prefixes used in older versions of the metric system are no longer used. For example, prefixes for multiples greater than one thousand are rarely applied to the gram or metre. In most contexts only a few, the most common, combinations are established. Unit prefixes that are much larger or smaller than encountered in practice are seldom used, albeit valid combinations. The choice of prefixes for a given unit has often arisen by convenience of use and historical developments. Some combinations, however, are more common than others. In general, prefixes are used with any metric unit, but may also be used with non-metric units.
The unit prefixes are always considered to be part of the unit, so that, e.g., in exponentiation, 1 km 2 means one square kilometre, not one thousand square metres, and 1 cm 3 means one cubic centimetre, not one hundredth of a cubic metre. Prefixes corresponding to powers of one thousand are usually preferred, however, units such as the hectopascal, hectare, decibel, centimetre, and centilitre, are commonly used. In addition to those listed in the "everyday use" table, the SI includes standardised prefixes for 10 15 ( peta), 10 18 ( exa), 10 21 ( zetta) and 10 24 ( yotta), and for 10 −15 ( femto), 10 −18 ( atto), 10 −21 ( zepto), and 10 −24 ( yocto).ĭistance marker on the Rhine: 36 (XXXVI) myriametres from BaselĪlthough formerly in use, the SI disallows combining prefixes the * microkilogram or * centimillimetre, for example, are not permitted.
The International Bureau of Weights and Measures has standardised twenty metric prefixes in resolutions dating from 1960 to 1991 for use with the International System of Units (SI). Some of the prefixes date back to the introduction of the metric system in the 1790s, but new prefixes have been added, and some have been revised. Each prefix has a unique symbol that is prepended to the unit symbol. The prefixes of the metric system precede a basic unit of measure to indicate a decadic multiple and fraction of a unit.
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