《Operating System Concepts》學(xué)習(xí)第 46 天，p512-p527 總結(jié)，總計(jì) 16 頁。

一、技術(shù)總結(jié)

1.front-end processor

(1)定義

Small computers that perform certain tasks in an overall system; used by some systems to manage I/O and offload the general-purpose CPU.

(2)示例

terminal concentrator。

二、英語總結(jié)(生詞：3)

1.malfunction

(1)malfunction: mal-("bad") + function

c/u. a situation in which a system stops working normally(故障)。

(2)示例

An operating system that uses protected memory can guard against many kinds of hardware and application errors, so that a complete system failure is not the usual result of each minor mechanical malfunction(《Operating System Concepts》第 511 頁)。

2.transient

(1)transitent: trans-("across, beyond") + ire("to go")

adj. lasting for only a short time; temporary(短暫的，暫時性的)。Transient means literally "go across", which implies "pass through sth rather than staying"。

(2)示例

Devices and I/O transfers can fail in many ways, either for transient reasons, as when a network becomes overloaded, or for “permanent” reasons, as when a disk controller becomes defective(《Operating System Concepts》第 512 頁)。

3.compensate

(1)compensate: com-("together, with") + pensare("weight, pay")

vt. give (sb) sth, like money, in recognition of loss, suffering or injure(補(bǔ)償)。vi. to offset an error, defect, or undesired effect(彌補(bǔ)(錯誤，缺陷，不希望的結(jié)果))。

(2)示例

示例1：His enthusiasm compensates for his lack of skil(他的熱情彌補(bǔ)了他技術(shù)上的不足)。

在這個例子中，使用 “enthusiasm” 來彌補(bǔ) “l(fā)ack of skill”。

示例2：Operating systems can often compensate effectively for transient failures. For instance, a disk read() failure results in a read() retry, and a network send() error results in a resend(), if the protocol so specifies(《Operating System Concepts》第 512 頁)。

在這個例子中，如果只看第一句“通常，操作系統(tǒng)能有效彌補(bǔ)(應(yīng)對)暫時性故障”，其實(shí)不大好理解，因?yàn)闆]有直接體現(xiàn)“使用什么來彌補(bǔ)什么”？翻譯為“彌補(bǔ)”也不大通暢。需要結(jié)合后面一句來理解。operating system 是怎么彌補(bǔ) transient failures 的呢？使用 “ read() retry” 來彌補(bǔ) “read() failure”, 使用 “resend()” 來彌補(bǔ) “send() error”。

從技術(shù)上來說不難理解，其實(shí)就是“重試機(jī)制”，但是如果不理解詞的意思，有時候就不能很好的理解作者想表達(dá)的意思。

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

第 12 章(I/O Systems)簡評：介紹 bus, controller, power management, STREAMS 等，也很抽象。

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)