3.1 存储系统概念

3.1.1 存储器的层次化结构

![Pasted image 20251130143511](../../../_assets/9aa4ba7-Pasted image 20251130143511.png)

介质

主存与Cache使用半导体作为存储介质，磁盘磁带通过磁性材料存储

存取方式

![Pasted image 20251130144643](../../../_assets/9b94b57-Pasted image 20251130144643.png)

读写方式

![Pasted image 20251130144805](../../../_assets/443e4e6-Pasted image 20251130144805.png)

易失性与破坏性

![Pasted image 20251130145003](../../../_assets/ed099c1-Pasted image 20251130145003.png)

3.1.2 存储器的性能指标

![Pasted image 20251130145251](../../../_assets/6e7c247-Pasted image 20251130145251.png)

3.2 主存储器

3.2.1 主存储器基本组成

![Pasted image 20251130150625](../../../_assets/6656d8e-Pasted image 20251130150625.png)

![Pasted image 20251130150551](../../../_assets/9b24cc5-Pasted image 20251130150551.png)

![Pasted image 20251130151049](../../../_assets/7fa083d-Pasted image 20251130151049.png)

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寻址

![Pasted image 20251130152107](../../../_assets/789c92d-Pasted image 20251130152107.png)

3.2.2 SRAM与DRAM

Dynamic Random Access Memory，动态RAM，DRAM用于主存。 Static Random Access Memory，静态RAM，SRAM用于Cache。

存储元

SRAM使用双稳态触发器，DRAM使用栅极电容 ![Pasted image 20251130153823](../../../_assets/7fe1436-Pasted image 20251130153823.png)

对比

![Pasted image 20251130153957](../../../_assets/9b7b56f-Pasted image 20251130153957.png)

刷新

刷新指在规定的时间内更新，因为电容中的电荷只能维持2ms，必须要充电

![Pasted image 20251130154533](../../../_assets/7715170-Pasted image 20251130154533.png) 通过这种行列分开的形式，能够减少选通信的数量，简化电路

![Pasted image 20251130155132](../../../_assets/99a8d27-Pasted image 20251130155132.png)

地址线复用

![Pasted image 20251130155310](../../../_assets/c52e08e-Pasted image 20251130155310.png)

3.2.3 ROM

![Pasted image 20251130160321](../../../_assets/022023c-Pasted image 20251130160321.png)

BIOS

![Pasted image 20251130160752](../../../_assets/f8fa871-Pasted image 20251130160752.png)

3.2.4 多模块存储器

双端口RAM已从2025年408大纲删除

多体并行存储器

每个存储器独立，具有相同的容量和读取速度

地位交叉编制实现了在连续读取时读取不同的存储体 ![Pasted image 20251130164045](../../../_assets/9a5a8f9-Pasted image 20251130164045.png)

![Pasted image 20251130164450](../../../_assets/11a1851-Pasted image 20251130164450.png)

单体多字存储器

![Pasted image 20251130164754](../../../_assets/0a02a4a-Pasted image 20251130164754.png)

3.3 主存储器与CPU的链接

位扩展

![Pasted image 20251130174747](../../../_assets/90f5777-Pasted image 20251130174747.png) ![Pasted image 20251130174659](../../../_assets/846b581-Pasted image 20251130174659.png)

字扩展

![Pasted image 20251130180647](../../../_assets/02470ad-Pasted image 20251130180647.png)

译码器

![Pasted image 20251130181239](../../../_assets/bfdd9a2-Pasted image 20251130181239.png)