内存是计算机中用于存储应用程序的存储组件。内存芯片被分成相等的部分,称为“CELLS” 。每个 Cell 由称为“ADDRESS”的二进制数唯一标识。例如,内存芯片配置表示为“ 64 K x 8” ,如下图所示。
可以从上面显示的内存芯片表示中获得以下信息:
1. 芯片中的数据空间 = 64K X 8
2. Cell 中的数据空间 = 8 位
3. 芯片中的地址空间 = =16 位
现在我们可以清楚地说明字节可寻址存储器和字可寻址存储器之间的区别。
Byte Addressable Memory | Word Addressable Memory |
---|---|
When the data space in the cell = 8 bits then the corresponding address space is called as Byte Address. | When the data space in the cell = word length of CPU then the corresponding address space is called as Word Address. |
Based on this data storage i.e. Bytewise storage, the memory chip configuration is named as Byte Addressable Memory. | Based on this data storage i.e. Wordwise storage, the memory chip configuration is named as Word Addressable Memory. |
For eg. : 64K X 8 chip has 16 bit Address and cell size = 8 bits (1 Byte) which means that in this chip, data is stored byte by byte. | For eg. : For a 16-bit CPU, 64K X 16 chip has 16 bit Address & cell size = 16 bits (Word Length of CPU) which means that in this chip, data is stored word by word. |
笔记 :
i) 需要注意的最重要的一点是,无论是字节地址还是字地址,地址大小都可以是任意位数(取决于芯片中的单元数),但单元大小因情况而异.
ii) 计算机设计中的默认内存配置是 Byte Addressable 。