在有一台处理机CPU和两台输入输出设备IO1和IO2,且能够实现抢先式多任务并行工作

题型:单项选择题

问题:

在有一台处理机CPU和两台输入输出设备IO1和IO2,且能够实现抢先式多任务并行工作的多道程序内,投入运行优先级由高到低的P1,P2,P3三个作业。它们使用设备的先后顺序和占用设备时间分别是:

作业P1:IO2(30毫秒) CPU(10毫秒) IO1(30毫秒) CPU(10毫秒)

作业P2:IO1(20毫秒) CPU(20毫秒) IO2(40毫秒)

作业P3:CPU(30毫秒) IO1(20毫秒)

在对于其他辅助操作时间可以忽略不计的假设下,作业P1,P2,P3从投入到完成所用的时间分别是 (55) 毫秒, (56) 毫秒和 (57) 毫秒。三个作业从投入运行到全部完成,CPU的利用率约为 (58) %,IO1的利用率约为 (59) %。

假定在系统中仅有这三个作业投入运行,各设备的利用率是指该设备的使用时间同作业进程全部完成所占用最长时间的比率。

(55)处填()。

A.60

B.67

C.70

D.78

E.80

F.89

G.90

H.100

I.110

J.120

考点:计算机软件水平考试中级软件设计师中级软件设计师上午试题
题型:单项选择题

Mrs. Black lives on Second Avenue. New Year is coming. She wants to send (寄) a card to her friend in Toronto, but she doesn’t know where the post office is. She asks her neighbor (邻居) Mary, “ Is there a post office near here? I want to send a card.”

“The post office is not near from here,” answers Mary, “but you don’t need to go to the post office to post the card. There is a mailboxin front of the supermarket. You can put your card into the mailbox”

小题1:Where does Mrs. Black live?

A.In New York.

B.In Toronto.

C.On Second Avenue.

D.On Green Street.小题2:What does Mrs. Black want to do?

A.She wants to go to the post office.

B.She wants to go to the supermarket.

C.She wants to send a card to Mary.

D.She wants to visit her friend.小题3:The post office is ________.

A.next to Mary’s house

B.not near Mrs. Black’s house

C.across from the supermarket

D.in front of Mary’s house.小题4:Mrs. Black and Mary are ________.

A.friends

B.sisters

C.mother and daughter

D.neighbors.小题5:What’s the meaning (意思) of mailbox

A.电子邮件

B.信箱

C.邮局

D.信封

题型:单项选择题

I think physics is _____ interesting subject.        [ ]

A. /

B. a

C. an

D. the

题型:单项选择题

Helen had to shout ________ above the sound of the music. [ ]

A. making herself hear    

B. to make herself hear  

C. making herself heard    

D. to make herself heard

题型:单项选择题

与他人交往的需要属于()。

A.遗传性需要

B.社会性需要

C.获得性需要

D.生理性需要

题型:单项选择题

起讫点中不包含广州市的高速有哪些:()

A、S1

B、S10

C、S28

D、S81

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