Difference between revisions of "Word"
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| − | + | In the widest sense, a '''word''' is an ordered group of bits considered together. In computer architecture, a word may denote data processed by the [[Central Processing Unit|CPU]], an instruction, an address, or the unit by which [[main memory]] is accessed. In early and simple computers, these were to a large extend the same width. However, contemporary practice is to give each [[byte]] in main memory its own address; instructions are often smaller than the [[ALU]] width; virtual and physical addresses are different size, etc. | |
Words are now usually a power-of-two multiple of an 8-bit byte in size, but in early computers, other word sizes were common. 36 bits was a very popular size on early [[mainframe]]s, such as the [[IBM 704]] and its descendants, the [[Honeywell 6000 series]], and the [[PDP-10]] family. However, small word sizes were common too, e.g. the 12-bit words of the [[PDP-8 family]]. | Words are now usually a power-of-two multiple of an 8-bit byte in size, but in early computers, other word sizes were common. 36 bits was a very popular size on early [[mainframe]]s, such as the [[IBM 704]] and its descendants, the [[Honeywell 6000 series]], and the [[PDP-10]] family. However, small word sizes were common too, e.g. the 12-bit words of the [[PDP-8 family]]. | ||
Latest revision as of 10:41, 11 August 2023
In the widest sense, a word is an ordered group of bits considered together. In computer architecture, a word may denote data processed by the CPU, an instruction, an address, or the unit by which main memory is accessed. In early and simple computers, these were to a large extend the same width. However, contemporary practice is to give each byte in main memory its own address; instructions are often smaller than the ALU width; virtual and physical addresses are different size, etc.
Words are now usually a power-of-two multiple of an 8-bit byte in size, but in early computers, other word sizes were common. 36 bits was a very popular size on early mainframes, such as the IBM 704 and its descendants, the Honeywell 6000 series, and the PDP-10 family. However, small word sizes were common too, e.g. the 12-bit words of the PDP-8 family.
