《Operating System Concepts》學習第 11 天，p76-p86 總結，總計 11 頁。

一、技術總結

1.mechanism & policy

(1)mechanisim 定義

An operation that defi nes how something will be done.

(2)policy 定義

A rule that defi nes what will be done.

(3)mechanism 和 policy 的區別

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、英語總結(生詞：3)

1.consensus

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

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

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 頁)。

示例：reach a consensus(達成共識)。

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“”。這個詞的意思不重要，重點是看構詞法。

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(阻礙)。

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 頁)。

關于英語的注解同步更新匯總到 https://github.com/codists/English-In-CS-Books 倉庫。

三、其它

前兩天 Typora 試用結束后就不給再使用了，于是體驗了下 Marktext ，發現從 Marktext 復制內容后粘貼到其它編輯器不能保持格式一致。于是決定購買 Typora，支持一下，但是，本來 14.99 刀，沒想到還有 1.2 刀的稅，最終 花費16.19 刀 。希望 Typora 能堅持久一點！

四、參考資料

1. 編程

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

2. 英語

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

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

歡迎搜索及關注：編程人(a_codists)