《Operating System Concepts》學習第 25 天，p228-p257 總結，總計 30 頁。

一、技術總結

1.algorithm evaluation

評估 CPU 調度算法需要考慮的因素有：CPU utilization, response time 或者 throughput。

基于以上幾個因素，選擇依據為：

(1)Maximizing CPU utilization under the constraint that the maximum response time is 300 milliseconds.

(2)Maximizing throughput such that turnaround time is (on average) linearly proportional to total execution time.

二、英語總結(生詞：2)

1.monotonic

(1)monotonic: mono-("one, single, along") + tonic("relating to tone")

adj. 1.monotonic literally means speaking in such a way that the sounds stays on the same note without going higher or lower(單調的，這里主要指聲音方面的)。2.varying in such a way that it either never decreases or never increases.

(2)示例

The rate-monotonic scheduling algorithm schedules periodic tasks using a static priority policy with preemption(《Operating System Concepts》第 230 頁)。

2.processing

(1)adjective 用法

In fact, a process may be interrupted at any point in its instruction stream, and the processing core may be assigned to execute instructions of another process(《Operating System Concepts》第 257 頁)。

在上面這個例子中，processing 用于修飾 core, 表示“ core is used for processing”。

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 5 章(CPU Scheduling)簡評：介紹 CPU 調度：調度算法，算法評估。再次感嘆，作者能把每個概念都介紹得清楚明了。

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)