《Operating System Concepts》阅读笔记：p76-p86

《Operating System Concepts》学习第 11 天，p76-p86 总结，总计 11 页。

一、技术总结

1.mechanism & policy

(1)mechanisim 定义

An operation that defi nes how something will be done.

(2)policy 定义

A rule that defi nes what will be done.

(3)mechanism 和 policy 的区别

Mechanisms determine how to do something; policies determine what will be done. For example, the timer construct (see Section 1.4.3) is a mechanism for ensuring CPU protection, but deciding how long the timer is to be set for a particular user is a policy decision.

二、英语总结(生词：3)

1.consensus

(1)consensus: con-("with, together") + entire("to feel, to think", 参考 sense)

s/u. to think or fell together, reflect agreement or harmony among a group(共识，一致意见).

示例：There is little consensus regarding which services should remain in the kernel and which should be implemented in user space(《Operating System Concepts》第 85 页)。

示例：reach a consensus(达成共识)。

2.neutrino

(1)neuter: ne-("not, no") + uter("either(of two)")

adj. a gender category that is neither masculine nor feminine(中性的)。

(2)neutral: neuter

adj. "neither the one nor the other, neither of two"(中立的)。

(3)neutrino: neutro-("neut") + -ino(diminutive suffix，indicate/denote small)

c.neutral particle smaller than a neutron(中微子)， neutron的意思是“”中子“”。这个词的意思不重要，重点是看构词法。

3.impediment

(1)impediment: im-("not, against") + *ped-("foot")

c. Literally, "to chain the foot", "to prevent movement"。Impediment refers to sth that hinders, obstructs, or slows down progress(阻碍)。

示例：

The overhead involved in copying messages and switching between processes has been the largest impediment to the growth of microkernel-based operating systems(《Operating System Concepts》第 86 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

前两天 Typora 试用结束后就不给再使用了，于是体验了下 Marktext ，发现从 Marktext 复制内容后粘贴到其它编辑器不能保持格式一致。于是决定购买 Typora，支持一下，但是，本来 14.99 刀，没想到还有 1.2 刀的税，最终 花费16.19 刀 。希望 Typora 能坚持久一点！

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

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