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The gigabyte ( or 〔The prefix ''giga'' may be pronounced two ways. (Gigabyte - Definition and More from the Free Merriam-Webster Dictionary )〕) is a multiple of the unit byte for digital information. The prefix ''giga'' means 109 in the International System of Units (SI), therefore one gigabyte is . The unit symbol for the gigabyte is GB. This definition is used in all contexts of science, engineering, business, and many areas of computing, including hard drive, solid state drive, and tape capacities, as well as data transmission speeds. However, the term is also used in some fields of computer science and information technology to denote (10243 or 230) bytes, particularly for sizes of RAM. The use of ''gigabyte'' is thus ambiguous. For semiconductor RAM, the gigabyte denotes . For hard drive capacities as described and marketed by the drive manufacturers, the gigabyte denotes , but when a 500-GB drive's capacity is displayed by, for example, Microsoft Windows, it is reported as ''465 GB'', where ''GB'' then means . To address this ambiguity, the binary prefixes are standardized in the International System of Quantities, each binary prefix denoting an integer power of 1024. With these prefixes, a memory module that is labeled as having the size ' is designated as ' (one gibibyte). ==Definition== The term ''gigabyte'' is commonly used to mean either 10003 bytes or 10243 bytes. The latter binary usage originated as compromise technical jargon for byte multiples that needed to be expressed in a power of 2, but lacked a convenient name. As 1024 (210) is approximately 1000 (103), roughly corresponding to SI multiples, it was used for binary multiples as well. In 1998 the International Electrotechnical Commission (IEC) published standards for binary prefixes, requiring that the gigabyte strictly denote 10003 bytes and gibibyte denote 10243 bytes. By the end of 2007, the IEC Standard had been adopted by the IEEE, EU, and NIST, and in 2009 it was incorporated in the International System of Quantities. Nevertheless, the term gigabyte continues to be widely used with the following two different meanings: 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「gigabyte」の詳細全文を読む スポンサード リンク
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