Giga-

Giga (/ˈdʒɪɡə/ or /ˈɡɪɡə/) is a unit prefix in the metric system denoting a factor of a (short-form) billion (10⁹ or 1000000000). It has the symbol G.

Giga is derived from the Greek word γίγας, 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 Conference in 1947: "The following prefixes to abbreviations for the names of units should be used: G giga 10⁹×".

When referring to information units in computing, such as gigabyte, giga may sometimes mean 1073741824 (2³⁰), although such use is inconsistent, contrary to standards and has been discouraged by the standards organizations. The inconsistency is that gigabit is never (or very rarely) used with the binary interpretation of the prefix, while gigabyte is sometimes used this way. The binary prefix gibi has been adopted for 2³⁰, while reserving giga exclusively for the metric definition.

Pronunciation

In English, the initial g of giga can be pronounced /ɡ/ (a hard g as in giggle), or /ˈdʒɪɡə/ (a soft g as in giant, like a j sound, which shares its Greek root).

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).

Giga (disambiguation)

Giga may refer to:

Prefix

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