小半年后将迎来一次重要的考试，从现在开始把以前学习的内容和新学到的内容做一个系统的整理。
Operating Systems - Internals and Design Principles
1 Computer System Overview
1.1 Basic Elements
Processor, Main memory, I/O modules, System bus
1.2 Processor Registers
PC - Program counter IR - Instruction register
MAR - Memory address register MBR - Memory buffer register
I/O AR - I/O address register I/O BR - I/O buffer register
User-visible registers - Data, Address, Index, Segment pointer, Stack pointer
Control ans status registers - PC, IR, Condition codes(flags)
1.3 Instruction execution
Fetch and Execute
1.4 Interrupts
Short and long I/O wait
1.5 The memory hierarchy
As one goes down the hierarchy, occur:
a. Decreasing cost per bit
b. Increasing capacity
c. Increasing access time
d. Decreasing frequency of access to the memory by the processor
1.6 Cache memory
Cache size, Block size, Mapping function, Replacement algorithm, Write policy.
Hit ratio increases then decreases when the block size keeps increasing.
Replace the block that is least likely to be needed in the near future.
least-recently-used (LRU) is a hardware mechanism.
1.6 I/O communication techniques
Programmed I/O, Interrupt-driven I/O, Direct memory access (DMA).
Review
In general, what are the strategies for exploiting spatial locality and temporal locality?
http://www.cnblogs.com/yanlingyin/archive/2012/02/11/2347116.html (局部性原理浅析)