Kibibyte
Encyclopedia
The kibibyte is a multiple of the unit byte
for quantities of digital information
. The binary prefix
kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission
(IEC) in 1999 and has been accepted for use by all major standards organizations. It was designed to replace the kilobyte
when used in computer science contexts to mean 1024 bytes, which conflicts with the SI definition of the prefix kilo, but it has seen little adoption by the computer industry.
The prefix kibi is derived as a portmanteau of the words kilo and binary, indicating its origin in the closeness in value to the SI prefix
kilo (1000). While the SI prefix is written with lowercase (k), the IEC prefix starts with an uppercase letter.
. The latter may be used in some contexts as a synonym for the kibibyte, but formally refers to 103 bytes = 1000 bytes, as the prefix is defined in the International System of Units
.
The binary interpretation of the metric prefixes causes relatively small differences with the smallest prefixes in the series, i.e. for kilo and mega, but grows to substantial differences beyond (see Deviation between powers of 1024 and powers of 1000).
In Introduction to MMIX, Donald Knuth
proposed that this unit be called a large kilobyte (abbreviated KKB). Other early proposals included using the Greek lowercase letter κ (kappa)
for 1024 bytes (and using k exclusively for 1000), bK, KB, and others. See Binary prefix#Early suggestions.
Adoption of the binary prefixes has been limited, primarily being used in open source software. In most cases, the kilobyte continues to be used to refer to a power of ten as well as a power of two.
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
for quantities of digital information
Information
Information in its most restricted technical sense is a message or collection of messages that consists of an ordered sequence of symbols, or it is the meaning that can be interpreted from such a message or collection of messages. Information can be recorded or transmitted. It can be recorded as...
. The binary prefix
Binary prefix
In computing, a binary prefix is a specifier or mnemonic that is prepended to the units of digital information, the bit and the byte, to indicate multiplication by a power of 2...
kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission
International Electrotechnical Commission
The International Electrotechnical Commission is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology"...
(IEC) in 1999 and has been accepted for use by all major standards organizations. It was designed to replace the kilobyte
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
when used in computer science contexts to mean 1024 bytes, which conflicts with the SI definition of the prefix kilo, but it has seen little adoption by the computer industry.
Definition
- 1 kibibyte = 210 bytes = 1024 bytes.
The prefix kibi is derived as a portmanteau of the words kilo and binary, indicating its origin in the closeness in value to the SI prefix
SI prefix
The International System of Units specifies a set of unit prefixes known as SI prefixes or metric prefixes. An SI prefix is a name that precedes a basic unit of measure to indicate a decadic multiple or fraction of the unit. Each prefix has a unique symbol that is prepended to the unit symbol...
kilo (1000). While the SI prefix is written with lowercase (k), the IEC prefix starts with an uppercase letter.
History
The kibibyte is closely related to the kilobyteKilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
. The latter may be used in some contexts as a synonym for the kibibyte, but formally refers to 103 bytes = 1000 bytes, as the prefix is defined in the International System of Units
International System of Units
The International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. The older metric system included several groups of units...
.
The binary interpretation of the metric prefixes causes relatively small differences with the smallest prefixes in the series, i.e. for kilo and mega, but grows to substantial differences beyond (see Deviation between powers of 1024 and powers of 1000).
In Introduction to MMIX, Donald Knuth
Donald Knuth
Donald Ervin Knuth is a computer scientist and Professor Emeritus at Stanford University.He is the author of the seminal multi-volume work The Art of Computer Programming. Knuth has been called the "father" of the analysis of algorithms...
proposed that this unit be called a large kilobyte (abbreviated KKB). Other early proposals included using the Greek lowercase letter κ (kappa)
Kappa
Kappa is the 10th letter of the Greek alphabet, used to represent the voiceless velar stop, or "k", sound in Ancient and Modern Greek. In the system of Greek numerals it has a value of 20. It was derived from the Phoenician letter Kaph...
for 1024 bytes (and using k exclusively for 1000), bK, KB, and others. See Binary prefix#Early suggestions.
Adoption of the binary prefixes has been limited, primarily being used in open source software. In most cases, the kilobyte continues to be used to refer to a power of ten as well as a power of two.