Giga- Explained

Giga- (or) is a unit prefix in the metric system denoting a factor of a short-scale billion or long-scale milliard (10⁹ or 1,000,000,000). It has the symbol G.

Giga- is derived from the Greek word Greek, Ancient (to 1453);: γίγας (gígas), meaning "giant". The Oxford English Dictionary reports the earliest written use of giga in this sense to be in the Reports of the IUPAC 14th Conférence Internationale de Chimie in 1947: "The following prefixes to abbreviations for the names of units should be used: G giga 10⁹×."^[1] However, it was already used in 1932 by the German organization Verband deutscher Elektrotechniker.^[2]

When referring to information units in computing, such as gigabyte, giga may sometimes mean (2³⁰); this causes ambiguity. Standards organizations discourage this and use giga- to refer to 10⁹ in this context too.^{[3] [4]} Gigabit is only rarely used with the binary interpretation of the prefix. The binary prefix gibi has been adopted for 2³⁰, while reserving giga exclusively for the metric definition.

Pronunciation

In English, the prefix giga can be pronounced (a hard g as in giggle), or (a soft g as in gigantic, which shares giga Ancient Greek root).^[5] A prominent example of this latter pronunciation is found in the pronunciation of gigawatts in the 1985 film Back to the Future.

According to the American writer Kevin Self, a German committee member of the International Electrotechnical Commission proposed giga as a prefix for 10⁹ in the 1920s, drawing on a verse (evidently "Anto-logie") by the German humorous poet Christian Morgenstern that appeared in the third (1908) edition of his German: Galgenlieder (Gallows Songs).^{[6] [7]} This suggests that a hard German pronounced as /[ɡ]/ was originally intended as the pronunciation. Self was unable to ascertain when the pronounced as //dʒ// (soft g) pronunciation came into occasional use, but claimed that as of 1995 it had returned to pronounced as //ɡ// (hard g).^{[8] [9]}

In 1998, a poll by the phonetician John C. Wells found that 84% of Britons preferred the pronunciation of gigabyte starting with pronounced as //ɡɪ// (as in gig), 9% with pronounced as //dʒɪ// (as in jig), 6% with pronounced as //ɡaɪ// (guy), and 1% with pronounced as //dʒaɪ// (as in giant).^[10]

Common usage

• gigahertz—clock rate of a CPU, for instance, 3 GHz =
• gigabit—bandwidth of a network link, for instance, 1 Gbit/s = .
• gigabyte—for instance, for hard disk capacity, 120 GB = ;
• gigayear or gigaannum—one billion (10⁹) years, sometimes abbreviated Gyr, but the preferred usage is Ga or, for years ago, GA.^[11]

Binary prefix

The notation represents 1,000,000,000 bytes or, in deprecated usage, 1,073,741,824 (2³⁰) bytes. Per IEC 60027-2 A.2 and ISO/IEC 80000 standards, the correct notation of 2³⁰ is gibi (symbol Gi).^[12] One gibibyte is 1,073,741,824 bytes or . Despite international standards, the use of = 2³⁰ B is widespread. A laptop advertised as having has 8,589,934,592 bytes of memory:, or . ^[13]

See also

• Binary prefix
• Gigabit Ethernet
• SI prefix
• List of commonly used taxonomic affixes
• RKM code

External links

• BIPM website

Notes and References

1. Web site: giga-, comb. form. October 2011. Oxford English Dictionary.
2. Web site: Wireless Engineer, 1932, issue 05, p. 252. . 2022-03-28 . 2022-03-28 . https://web.archive.org/web/20220328040119/https://worldradiohistory.com/UK/Experimental-Wireless/30s/Wireless-Engineer-1932-05-S-OCR.pdf . live .
3. Book: The International System of Units (SI). https://web.archive.org/web/20060813144253/http://www.bipm.org/utils/common/pdf/si_brochure_8.pdf . 2006-08-13 . live. 2007-02-25. 8th. 2006. STEDI Media. Paris. fr, en. 92-822-2213-6. 127. §3.1 SI prefixes. [Side note:] These SI prefixes refer strictly to powers of 10. They should not be used to indicate powers of 2 (for example, one kilobit represents 1000 bits and not 1024 bits). The IEC has adopted prefixes for binary powers in the international standard IEC 60027-2: 2005, third edition, Letter symbols to be used in electrical technology — Part 2: Telecommunications and electronics. The names and symbols for the prefixes corresponding to 2¹⁰, 2²⁰, 2³⁰, 2⁴⁰, 2⁵⁰, and 2⁶⁰ are, respectively: kibi, Ki; mebi, Mi; gibi, Gi; tebi, Ti; pebi, Pi; and exbi, Ei. Thus, for example, one kibibyte would be written: 1 KiB = 2¹⁰ B = 1024 B, where B denotes a byte. Although these prefixes are not part of the SI, they should be used in the field of information technology to avoid the incorrect usage of the SI prefixes..
4. http://physics.nist.gov/cuu/pdf/sp811.pdf NIST Guide for the Use of the International System of Units (Appendix D. ref 5)
5. Web site: SI prefixes and their etymologies . US Metric Association . 27 November 2019.
6. Book: Morgenstern . Christian . Christian Morgenstern . . German: Galgenlieder nebst dem 'Gingganz' . 1917 . Bruno Cassirer . . Berlin, Germany . 52 . 22 . de . [First four lines:] German: Im Anfang lebte, wie bekannt, / als größter Säuger der ''Gig''-ant. / Wobei ''gig'' eine Zahl ist, die / es nicht mehr gibt, - so groß war sie!|italic=unset. [These lines are the only appearance of ''gig'' in the book. {{lang|de|Gigant}} is German for "giant"; cf. "gigantic".]
7. Book: Morgenstern . Christian . Christian Morgenstern . Gallows Songs: Christian Morgenstern's "Galgenlieder", Bilingual Edition: A Selection . 1963 . Knight . Max . Max Knight . University of California Press . 9780520008847 . 24–25 . 20 February 2016 . [Translation:] Of yore, on earth was dominant / the biggest mammal: the Gig-ant. / ("Gig" is a numeral so vast, / it's been extinct for ages past.).
8. Self . Kevin . Technically speaking . Spectrum . 18 . . October 1994.
9. Self . Kevin . Technically speaking . Spectrum . 16 . . April 1995.
10. Wells, J. C. (1998). LPD pronunciation preference poll 1998.
11. Wilcock . Bruce . July 1967 . Megayear and Gigayear . Nature . en . 215 . 5096 . 102–102 . 10.1038/215102b0 . 1476-4687.
12. Web site: Definitions of the SI units: The binary prefixes . 2023-04-05 . physics.nist.gov.
13. Web site: GB Vs GiB: What’s The Difference? - MASV . 2024-08-08 . massive.io . en.