kilobyte
Pluralkilobytes
- 1A unit of digital information equal to one thousand (1,000) bytes.
Roughly the amount of data in a short paragraph of plain text.
The configuration file was barely a kilobyte in size.
Early home computers shipped with storage measured in kilobytes.
Note
The reading that takes the prefix at its word: kilo- means "thousand," so this kilobyte is 10³ bytes exactly, the decimal convention of SI units. It is the sense networking favors, where data moves at rates per second. Harold R. Dell's 1969 patent already speaks of 500 kilobytes per second. When the size must be unambiguous, keep it distinct from the 1,024-byte memory sense, which uses the same word.
- 2A unit of digital information equal to 1,024 bytes, used especially when describing computer memory such as RAM.
Like rounding 1,024 down to "about a thousand" for everyday convenience.
Each kilobyte of RAM in those early systems actually contained 1,024 bytes.
The vintage console advertised its memory as sixteen kilobytes.
Note
Memory specifications count in the binary convention, so the round figure here is 2¹⁰, or 1,024 bytes, rather than a clean thousand. Strictly, that quantity is a kibibyte. Kilobyte in this sense is informal and survives mostly in RAM capacities. Hisashi Horikoshi's 1969 patent for a memory control system counts this way, with 1-kilobyte sectors and a 4-kilobyte buffer. In careful technical writing, prefer kibibyte when 1,024 is meant.
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Origin
Coined in the 1960s from the prefix kilo- ("thousand") combined with byte.