In some computer, individual address is assigned for each byte of information, and it is called byte-addressable computer. In this computer, one memory word contains one or more memory bytes which can be addressed individually.

A byte addressable 32-bit computer, each memory word contains 4 bytes. A possible way of address assignment is shown in figure3.1. The address of a word is always integer multiple of 4.

The main memory is usually designed to store and retrieve data in word length quantities. The word length of a computer is generally defined by the number of bits actually stored or retrieved in one main memory access.

Consider a machine with 32 bit address bus. If the word size is 32 bit, then the high order 30 bit will specify the address of a word. If we want to access any byte of the word, then it can be specified by the lower two bit of the address bus.