 | This article includes a list of general references, but it lacks sufficient corresponding inline citations. (October 2009) |
| Computer architecture bit widths |
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| Binary floating-point precision |
| Decimal floating-point precision |
In computer architecture, 18-bit integers, memory addresses, or other data units are those that are 18 bits (2.25 octets) wide. Also, 18-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers, address buses, or data buses of that size.
Eighteen binary digits have 262,144 (1000000 octal, 40000 hexadecimal) distinct combinations.
Eighteen bits was a common word size for smaller computers in the 1960s, when large computers often using 36 bit words and 6-bit character sets, sometimes implemented as extensions of BCD, were the norm. There were also 18-bit teletypes experimented with in the 1940s.