问题 问答题

设某计算机系统有一个CPU,一台输入设备、一台打印机。现有两个进程同时进入就绪状态,且进程A先得到CPU运行,进程B后运行。进程A的运动轨迹为:计算50ms,打印信息100ms,再计算50ms,打印信息100ms结束。进程B的运行轨迹为:计算50ms,输入数据80ms,再计算100ms结束。试画出它们的时序关系图,并说明开始运行后,CPU有无空闲等待计算CPU的利用率。

答案

参考答案:运行次序为:
0~50ms A计算
50~100ms B计算,A打印
100~150ms A打印,B输入
150~200ms A计算,其中150~180ms B继续输入
200~300ms A打印,B计算
运行开始后,在100~150ms时,CPU空闲等待。CPU利用率为:
250/300=83.3%。

完形填空

A green life sometimes just needs a good idea like sharing cars.It’s a new way of thinking.You can use a car but you don’t need to own it Now the idea of “car sharing” has become       in many countries.

As we know ,most cars       in garages for much time.In fact,we drive our own cars          one or two hours a day on average(平均).    When we don’t use them,we have to pay for parking and        things.That costs too much money.To       money,some people come up with the idea of “car sharing”.If we share a car, we’ll only        when we use it.

Now many people are starting to do car sharing.In Switzerland,almost 40,000 people have          it.Japan is also trying to make       popular around the country.

Car sharing is the beginning of a new idea in      .It is also very nice for us to travel everywhere    buying a car.Do you love to share a car with others?                                                                         

小题1:A.popular            B.interesting         C.funny          

小题2:A.are washed         B.are driven         C.are parked      

小题3:A.as far as            B.as long as          C.as much as      

小题4:A.the other           B.others             C.other        

小题5:A.make              B.save              C.find            

小题6:A.spend              B.cost              C.pay

小题7:A.joined             B.covered            C.take part

小题8:A.time saving         B.money saving       C.car sharing   

小题9:A.fashion           B.transportation       C. the world

小题10:A.without          B.with              C.by 

判断题