Kilobyte
The kilobyte (symbol KB)[1] is a multiple of the unit byte for digital information. Historically and in common usage, a kilobyte refers to 1024 (210) bytes in most fields of computer science and information technology.[2][3][4] However, hard disk drives measure capacity in strict accordance with the rule of the International System of Units’ unit prefixes (prefixes like kilo- and mega-) that are based on decimal math.[5][6] In such mass storage contexts, megabyte equals precisely 1,000,000 bytes and gigabyte is precisely 1,000 times greater than a megabyte. This association suggests that kilobyte can also denote 1,000 bytes in the context of mass storage. Thus, “kilobyte” and its symbol “KB” can be ambiguous, their exact value (1,024 or 1,000) dependent upon context.
In December 1998, an international standards organization attempted to address these dual definitions of the conventional prefixes by proposing unique binary prefixes and prefix symbols to denote multiples of 1024, such as “kibibyte (KiB)”, which exclusively denotes 210 or 1024 bytes.[7] Had this proposal been widely and consistently adopted, it would have liberated the standard unit prefixes to unambiguously refer only to their strict decimal definitions wherein kilobyte would be understood to represent only 1000 bytes. However, in the over‑12 years that have since elapsed, the proposal has seen little adoption by the computer industry.[8][9][10][11]
See also
References
- ^ Note that lowercase “k” is the proper unit symbol for the prefix kilo. Uppercase “K” is properly the unit symbol for the unit of thermodynamic temperature kelvin. Moreover, the rule of the International System of Units (the SI) is that when describing the magnitude of a measure, a space always separates the numeric value of a quantity and its unit symbol, e.g. “1 kB”. Nonetheless, it is exceedingly common within the computing industry when denoting binary capacity—particularly in marketing literature and product packaging—to use uppercase K and no space (1KB), although “1 KB” is not incorrect and is often considered more suitable in technical writing.
- ^ definition of kilobyte from Oxford Dictionaries Online. Askoxford.com. Retrieved on 2011-01-07.
- ^ Kilobyte – Definition and More from the Free Merriam-Webster Dictionary. Merriam-webster.com (2010-08-13). Retrieved on 2011-01-07.
- ^ Kilobyte | Define Kilobyte at Dictionary.com. Dictionary.reference.com (1995-09-29). Retrieved on 2011-01-07.
- ^ Drive displays a smaller capacity than the indicated size on the drive label
- ^ i.e. see HGST, Samsung, Seagate, Toshiba and Western Digital websites
- ^ National Institute of Standards and Technology. "Prefixes for binary multiples". http://physics.nist.gov/cuu/Units/binary.html. "In December 1998 the International Electrotechnical Commission (IEC) [...] approved as an IEC International Standard names and symbols for prefixes for binary multiples for use in the fields of data processing and data transmission."
- ^ Upgrading and Repairing PCs, Scott Mueller, Pg. 596, ISBN 0789729741
- ^ The silicon web: physics for the Internet age, Michael G. Raymer, Pg. 40, ISBN 9781439803110
- ^ Knuth: Recent News. Cs-staff.stanford.edu. Retrieved on 2011-01-07.
- ^ Atwood, Jeff. (2007-09-10) Gigabyte: Decimal vs. Binary. Coding Horror. Retrieved on 2011-01-07.
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