《Operating System Concepts》学习第 60 天，p700-p732 总结，总计 33 页。

一、技术总结

1.Virtual machine manager (VMM)

The computer function that manages the virtual machine; also called a hypervisor.

VMM 也称为 hypervisor。

2.types of VMs

type 0 hypervisor、type 1 hypervisor、type 2 hypervisor。

3.bridging

The guests can be “directly” connected to the network by an IP address that is seen by the broader network (this is known as bridging).

二、英语总结(生词：3)

1.permeate

(1)permeate: per-("forward", hence "through") + *mei-("to go, move")

vi/vt. permeate literally means go through. to spread through and be present in every part of it(渗透)。

(2)示例

Virtualization permeates all aspects of computing(《Operating System Concepts》第 700 页)。

(3)permeate vs pervade

暂时没看到明显的区分标准，TBD。

2.illusion

(1)illusion:in-("in") + ludere("to play")

c/u. a false perception(感知，感觉) by the senses(错觉，幻觉)。

(2)示例

The fundamental idea behind a virtual machine is to abstract the hardware of a single computer (the CPU, memory, disk drives, network interface cards, and so forth) into several different execution environments, thereby creating the illusion that each separate environment is running on its own private computer(《Operating System Concepts》第 701 页)。

3.leeway

(1)leeway: lee("a nutical term meaning the sheltered side of a ship(the side away from the wind)") + way("movement")

u. originally, leeway described how much a ship drifted sideways(dowawind) due to wind or currents(最初，“leeway”描述的是由于风或洋流，船只侧向（顺风）漂移的程度)。freedom to act within particular limits()。

(2)示例

In the area of I/O, hypervisors have some leeway and can be less concerned with how they represent the underlying hardware to their guests(《Operating System Concepts》第 722 页)。

关于英语的注解同步更新汇总到 https://github.com/codists/English-In-CS-Books 仓库。

三、其它

第 18 章(Virtual Machines)简评：关于虚拟机，作为开发而言，可能相对更熟悉 example(如：VMWare Workstation, Oracle VirtualBox)。

四、参考资料

1. 编程

(1) Abraham Silberschatz，Peter Baer Galvin，Greg Gagne《Operating System Concepts》：https://book.douban.com/subject/30272539/

2. 英语

(1) Etymology Dictionary：https://www.etymonline.com

(2) Cambridge Dictionary：https://dictionary.cambridge.org

欢迎搜索及关注：编程人(a_codists)