Editing Gigabyte (section)

==Consumer confusion==
Since the first disk drive, the [[IBM 350]], disk drive manufacturers expressed [[hard drive]] capacities using decimal prefixes. With the advent of gigabyte-range drive capacities, manufacturers labelled many consumer [[hard drive]], [[solid-state drive]] and [[USB flash drive]] capacities in certain size classes expressed in decimal gigabytes, such as "500 GB". The exact capacity of a given drive model is usually slightly larger than the class designation. Practically all manufacturers of hard disk drives and flash-memory disk devices<ref name="sandisk_gigabyte"/><ref name="kingston_gigabyte"/> continue to define one gigabyte as {{gaps|1|000|000|000|bytes}}, which is displayed on the packaging. Some operating systems such as [[Mac OS X]],<ref>{{Cite web|url=https://support.apple.com/en-us/HT201402|title=How OS X and iOS report storage capacity - Apple Support|website=support.apple.com|access-date=2016-06-29}}</ref> [[iOS]], [[Android (operating system)|Android]],{{Citation needed|date=March 2025}} [[Ubuntu]],<ref>{{cite web |title=UnitsPolicy |url=https://wiki.ubuntu.com/UnitsPolicy |website=Ubuntu Wiki |publisher=Ubuntu |access-date=9 January 2022 |archive-date=18 November 2021 |archive-url=https://web.archive.org/web/20211118114902/https://wiki.ubuntu.com/UnitsPolicy |url-status=live }}</ref> and [[Debian]]<ref>{{cite web |title=ConsistentUnitPrefixes |url=https://wiki.debian.org/ConsistentUnitPrefixes |website=Debian Wiki |access-date=9 January 2022 |archive-date=3 December 2021 |archive-url=https://web.archive.org/web/20211203075715/https://wiki.debian.org/ConsistentUnitPrefixes |url-status=live }}</ref> express hard drive capacity or file size using decimal multipliers, while others such as [[Microsoft Windows]] (including [[Windows Phone]]) report file size using binary multipliers. This discrepancy causes confusion, as a disk with an advertised capacity of, for example, {{nowrap|400 GB}} (meaning {{gaps|400|000|000|000|bytes}}, equal to 372&nbsp;GiB) might be reported by the operating system as "{{nowrap|372 GB}}".

For [[random-access memory|RAM]], the [[JEDEC memory standards]] use ''IEEE 100'' nomenclature which quote the gigabyte as {{gaps|1|073|741|824|bytes}} (2<sup>30</sup> bytes).<ref>{{Cite journal
  | last = JEDEC Solid State Technology Association
  | title = Terms, Definitions, and Letter Symbols for Microcomputers, Microprocessors, and Memory Integrated Circuits
  | journal = Jesd 100B.01
  | date = December 2002
  | url = http://www.jedec.org/download/search/JESD100B01.pdf
  }}</ref>

The difference between units based on decimal and binary prefixes increases as a [[Semilog|semi-logarithmic]] (linear-log) function—for example, the decimal kilobyte value is nearly 98% of the kibibyte, a [[megabyte]] is under 96% of a mebibyte, and a gigabyte is just over 93% of a gibibyte value. This means that a 300&nbsp;GB (279&nbsp;GiB) hard disk might be indicated variously as "300 GB", "279&nbsp;GB" or "279 GiB", depending on the operating system. As storage sizes increase and larger units are used, these differences become more pronounced.

===US lawsuits===
A lawsuit decided in 2019 that arose from alleged breach of contract and other claims over the binary and decimal definitions used for "gigabyte" have ended in favour of the manufacturers, with courts holding that the legal definition of gigabyte or GB is 1&nbsp;GB = 1,000,000,000 (10<sup>9</sup>) bytes (the decimal definition). Specifically, the courts held that "the U.S. Congress has deemed the decimal definition of gigabyte to be the 'preferred' one for the purposes of 'U.S. trade and commerce' .... The California Legislature has likewise adopted the decimal system for all 'transactions in this state'."<ref name="Order Granting Motion to Dismiss"/>

Earlier lawsuits had ended in settlement with no court ruling on the question, such as a lawsuit against drive manufacturer [[Western Digital]].<ref name="WesternDigital">{{cite web
  | last = Mook
  | first = Nate
  | date = 2006-06-28
  | url = http://www.betanews.com/article/Western-Digital-Settles-Capacity-Suit/1151510648
  | title = Western Digital Settles Capacity Suit
  | publisher = betanews
  | access-date = 2009-03-30
}}</ref><ref name="Baskin-2006-02-01">{{cite web
  | last = Baskin
  | first = Scott D.
  | date = 2006-02-01
  | url = http://www.wdc.com/settlement/docs/document20.htm
  | title = Defendant Western Digital Corporation's Brief in Support of Plaintiff's Motion for Preliminary Approval
  | work = Orin Safier v. Western Digital Corporation
  | publisher = [[Western Digital Corporation]]
  | access-date = 2009-03-30
}}</ref> Western Digital settled the challenge and added explicit disclaimers to products that the usable capacity may differ from the advertised capacity.<ref name="WesternDigital"/>
Seagate was sued on similar grounds and also settled.<ref name="WesternDigital"/><ref name="Seagate">{{cite news
  | last = Judge
  | first = Peter
  | date = 2007-10-26
  | url = https://www.zdnet.com/article/seagate-pays-out-over-gigabyte-definition/
  | title = Seagate pays out over gigabyte definition
  | work = ZDNet
  | access-date = 2014-09-16
}}</ref>

===Other contexts===
Because of their physical design, the capacity of modern computer random-access memory devices, such as [[DIMM]] modules, is always a multiple of a power of 1024. It is thus convenient to use prefixes denoting powers of 1024, known as [[binary prefixes]], in describing them. For example, a memory capacity of {{gaps|1|073|741|824|bytes}} (1024<sup>3</sup> B) is conveniently expressed as 1&nbsp;[[gibibyte|GiB]] rather than as 1.074&nbsp;GB. The former specification is, however, often quoted as "1&nbsp;GB" when applied to random-access memory.<ref name=TS-GiB>{{cite web|last1=Percival|first1=Colin|title=Why is 1 GB equal to 10^9 bytes instead of 2^30?|url=http://www.tarsnap.com/GB-why.html|publisher=tarsnap.com|access-date=1 November 2015}}</ref>

Software allocates memory in varying degrees of granularity as needed to fulfill data structure requirements and binary multiples are usually not required. Other computer capacities and rates, like [[Computer storage|storage]] hardware size, [[data transfer rates]], [[clock speed]]s, [[FLOPS|operations per second]], etc. are usually presented in decimal units. For example, the manufacturer of a "300&nbsp;GB" hard drive is claiming a capacity of {{gaps|300|000|000|000|bytes}}, not 300&nbsp;×&nbsp;1024<sup>3</sup> (which would be {{gaps|322|122|547|200}}) bytes.