《Operating System Concepts》學習第 48 天，p552-p579 總結，總計 28 頁。

一、技術總結

1.file descriptor/file handle

(1)file descriptor(fd)

UNIX open-file pointer, created and returned to a process when it opens a file.

(2)file handle

Windows name for the open-file file descriptor.

2.allocation methods

(1)contiguous allocation

(2)linked allocation

(3)indexed allocation

3.Free-Space management

(1)bitmap/bit vector

Frequently, the free-space list is implemented as a bitmap or bit vector——bitmap/bit vector是實現(xiàn) free-space list 的一種方式。

1)定義：A string of n binary digits that can be used to represent the status of n items. The availability of each item is indicated by the value of a binary digit: 0 means that the resource is available, while 1 indicates that it is unavailable (or vice versa).

2)示例：001111001111110001100000011100000 ...

3)linked list

二、英語總結(生詞：1)

1.sacrifice

(1)sacrifice: sacr-("sacred, holy, 神圣的") + -fice("to do, to make")

vt. sacrifice literally means "to make sacred, to make holy", over time, it evolves to mean "give up sth valuable for a higher purpose(犧牲)"。

(2)示例

For example, a temporary file system is used for fast storage and retrieval of nonpersistent files, while the default secondary storage file system (such as Linux ext4) sacrifices performance for reliability and features(《Operating System Concepts》第 563 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

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

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