《Operating System Concepts》學(xué)習(xí)第 33 天，p389-p407 總結(jié)，總計 19 頁。

一、技術(shù)總結(jié)

1.virtual memeory

(1)定義

A technique that allows the execution of a process that is not completely in memory. Also, separation of computer memory address space from physical into logical, allowing easier programming and larger name space.

(2)實現(xiàn)方式

1）demand paging

demand--(on demand: when needed)。

2.page-replacement algorithm

In memory management, the algorithm that chooses which victim frame of physical memory will be replaced by a needed new (1)FIFO pagte replacement

(2)optimal page replacement

(3)LRU page replacement

二、英語總結(jié)(生詞：3)

1.precaution

(1)caution: *keu-("to see, observe")

u. great care and attention(小心, 謹慎)。

(2)precaution: pre-("before") + caution

c. an action taken in advance to prevent sth unpleasant, dangerous or inconvinient from happening(預(yù)防措施)。

(3)示例

Dynamic linking can help to ease this restriction, but it generally requires special precautions and extra work by the programmer(《Operating System Concepts》第 390 頁)。

2.confer

(1)confer: con-("together") + fere("to bear, carry")

vi/vt. to give sth(a title, degree, benefit or right)(給予)。

(2)示例

The ability to execute a program that is only partially in memory would confer many benefits(《Operating System Concepts》第 390 頁)。

3.perceive

(1)perceive: per-("thoroughly, completely, entirely") + capere("to take, to grasp")

Perceive literally means "to take entirely", figuratively, means "to grasp with the mind(to view(看待)， to understand(理解)，to comprehend)"；

vt. be come aware of sth。

(2)示例

1.Virtual memory involves the separation of logical memory as perceived by developers from physical memory(《Operating System Concepts》第 390 頁)。

在上面這個例子中，整句話的意思是“虛擬內(nèi)存涉及將開發(fā)者所感知的邏輯內(nèi)存與物理內(nèi)存分離”。

2.His mouth fell open as he perceived the truth(當他意識到真相時，他的嘴張得大大的)。

之前一直不能很好的理解 perceive 的意思，大概是因為對 aware/awareness 的理解一直局限于“意識”，其實也可以擴展為為“對......的認識，感知，理解，明白”。

關(guān)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

今天沒有什么想說的。

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

(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)