问题 单项选择题

某计算机的时钟频率为600MHz,测试该计算机的程序使用4种类型的指令。每种指令的数量及所需指令时钟数(CPI)如表8-1所示,则该计算机的运算速度约为 (5) MIPS。
表8-1 各指令数量及其时钟数表

指令类型 指令数目(条) 每条指令需时钟数
1 140000 1
2 30000 2
3 24000 4
4 20000 6

A.106.76

B.207.32

C.308.64

D.1166.40

答案

参考答案:C

解析:[要点解析] 计算机执行指令的平均时钟数为总时钟数除以总条数,即本试题所给出的表8-1中指令的算术平均值。
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即指令的平均时钟数为1.944个时钟周期。
该计算机的速度为平均每秒钟所执行的指令条数,即其时钟在1s中有多少个1.944个时钟周期。用 MIPS表示每秒百万条指令,则:
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单项选择题 A1/A2型题
单项选择题

On the ground floor of the Federal Reserve building in Washington, DC, there is an electronic game which tests a visitor’s skill at setting interest rates. You have to decide how to respond to events such as rising inflation or a stockmarket crash. If you get all the answers right, the machine declares you the next Fed chairman. In real life, because of huge uncertainties about data and how the economy works, there is no obviously right answer to the question of when to change interest rates. Nor is there any easy test of who will make the best Fed chairman. So who would The Economist select for the job

Alan Greenspan will retire as Fed chairman on January 31st, after a mere 181/2 years in the job. So George Bush needs to nominate a successor soon. Mr. Bush has a penchant for picking his pals to fill top jobs: last week he nominated his personal lawyer Harriet Miers to the Supreme Court. But his personal bank manager really would not cut the mustard as Fed chairman. This is the most important economic-policy job in America—indeed in the whole world. The Fed chairman sets interest rates with the aim of controlling inflation, which in turn helps determine the value of the dollar, the world’s main reserve currency. It is hardly surprising that financial markets worldwide can rise or fall on his every word.

Financial markets are typically more volatile during the first year after the handover to a new chairman than during the rest of his tenure. In October 1987,barely two months after Mr. Greenspan took office, the stock market crashed. Current conditions for a handover are hardly ideal. America’s economy has never looked so unbalanced, with a negative household savings rate, a housing bubble, a hefty budget deficit, a record current-account deficit and rising inflation. Figures due on October 14th are expected to show that the 12-monthrate of inflation has risen above 4% —its highest since 1991.

Which of the following questions does the text discuss()

A. What is the content of the electronic game

B. Who could fill Alan Greenspan’s shoes

C. How to respond to events such as rising inflation

D. Who could change interest rates