Computer science 学习笔记操作系统(1)

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)