《Operating System Concepts》學習第 71 天，p808-p820 總結，總計 13 頁。

一、技術總結

1./proc

/proc 是一個虛擬的文件系統。

二、英語總結(生詞：2)

1.unidirectional

(1)unidirectional: uni-("one") + directional

adj. moving or operating in a single direction(單向的)。

(2)示例

Traditionally, these requests have been scheduled according to a unidirectional-elevator (C-SCAN) algorithm that exploits the order in which requests are inserted in and removed from the lists(《Operating System Concepts》第 811 頁)。

2.drawback

(1)drawback: draw("pull") + back("opposite of forward")

c. drawback literally means sth that pulls back--a disvantage or obstacle. a disvantage or the negative part of a situation(缺點，不利因素)。

(2)示例

Historically, UNIX implementations of this mechanism have had several drawbacks(《Operating System Concepts》第 816 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

第 20 章(The Linux System)簡評：從 History, Process Manage, Scheduling 等方面介紹 Linux 系統，放在整本書的末尾感覺有些畫蛇添足，因為這些內容在之前都有介過，沒有太大的不同。

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)