《Operating System Concepts》學(xué)習(xí)第 18 天，p177-p178 總結(jié)，總計(jì) 2 頁(yè)。

一、技術(shù)總結(jié)

1.implicit thread

A programming model that transfers the creation and management of threading from application developers to compilers and run-time libraries.

2.thread pool

Unlimited threads could exhaust system resources, such as CPU time or memory. One solution to this problem is to use a thread pool.

thread pool 是一種解決方案(solution)：A thread pool is a solution where a number of threads are created at process startup and placed in a pool, waiting for work.

二、英語(yǔ)總結(jié)(生詞：3)

1.trivial

(1)trivial: ("three") + via("road")

adj. Trivial is from trivialis("a place three roads meet"), over time, trivial means "havingf little value and importance(微不足道的)"。

(2)示例

Designing such applications is not a trivial undertaking: programmers must address not only the challenges outlined in Section 4.2 but additional difficulties as well(《Operating System Concepts》第 177 頁(yè))。

2.discard

(1)discard: dis("away") + card

vt. Historically, "discard" meant "remove a card from one's hand" in a card game. Over time, discard means "to throw away sth(拋棄，丟棄)", "to get rid of sth(擺脫)" when sth is no longer useful or needed(這是 discard 的使用語(yǔ)境)。

(2)示例

he first issue concerns the amount of time required to create the thread, together with the fact that the thread will be discarded once it has completed its work(《Operating System Concepts》第 177 頁(yè))。

在這個(gè)例子中， “discard the thread” 意思是 "terminate the thread, destroy the thread"。

3.resume

(1)resume: re-("again") + sumere("to take")

vi/vt. Resume literally means "to take again", over time, it envolve to mean "continue doing sth after a pause"。

(2)示例

When a server receives a request, rather than creating a thread, it instead submits the request to the thread pool and resumes waiting for additional requests(《Operating System Concepts》第 177 頁(yè))。

在上面這個(gè)句子中，resume 也是“continue doing sth after a pause”的意思。當(dāng)然，英語(yǔ)中有時(shí)候?yàn)榱撕?jiǎn)潔，往往會(huì)省略一些內(nèi)容，為了更好的理解，這里句子可以改成：

When a server receives a request, rather than creating a thread, it instead stop waiting to submit the request to the thread pool. After submitting the request, server resumes waiting for additional requests.

總之，要理解resume的在具體上下文中的含義，就要把握住“continue doing sth after a pause”的思想。如果句子不全不好理解，就先把句子補(bǔ)全去理解。

關(guān)于英語(yǔ)的注解同步更新匯總到 https://github.com/codists/English-In-CS-Books 倉(cāng)庫(kù)。

三、其它

今天沒(méi)有什么想說(shuō)的。

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(yǔ)

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

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

歡迎搜索及關(guān)注：編程人(a_codists)