问题 单项选择题

某计算机主存按字节编址,主存与高速缓存Cache的地址变换采用组相联映像方式(即组内全相联,组问直接映像)。高速缓存分为2组,每组包含4块,块的大小为512B,主存容量为1MB。构成高速缓存的地址变换表相联存储器容量为 (31) bit。每次参与比较的存储单元为 (32) 个。

A.1

B.2

C.4

D.8

答案

参考答案:C

解析:[要点解析]
本试题的解答思路如下。①由于主存容量为1MB=220,高速缓存分为2=21组(即区内组号为1位),每组包含4=22块(即组内块号为2位),块的大小为512B=29(即块内地址为9位),因此主存区号=20-1-2-9=8位。
②主存与高速缓存(Cache的地址变换采用组相联映像方式(即组内全相联,组间直接映像),在高速缓存的地址变换表的相联存储器中,存放的用于比较的是8位的主存区号和2位的组内块号,因此相联存储器的一个单元应存放10位二进制数。
③由于高速缓存共有8块,则高速缓存的地址变换表的相联存储器的容量应为8×10位。
④由于组问采用直接映像,不需要进行比较,但组内采用全相联映像,需要在一组的4块内进行比较,故每次参与比较的存储单元为4个。

阅读理解

Are You Ready for College?

Before you send in your college applications, keep this in mind: it’s not the norm (准则) in every culture for students to go to college right out of high school.

 小题1:So if you find yourself applying for college simply because it’s the thing to do after high school, think again. Going to college right after high school may be the norm in your community, but it’s not the norm everywhere and it may not be the best decision for you.

 小题2: Yes, higher education often gives young people a big advantage in the working world, but not always. A solid technical or business school application can give you an advantage as well, and if the environment seems like a better one for you than a traditional college campus, this might be your best choice. A lot of people lead successful lives with a high school education and years of work experience.

The price of a college or university education has become a serious burden for young people and their families.  小题3: In some cases, putting off college for a year or two while a student earns money full time can make sense.  小题4:

 小题5: Almost all students suffer from homesickness, but for some students, the transition may be too much to deal with.

A.Is going to college always the best choice for high school graduates?

B.Spend some time considering your choices before sending in your applications.

C.Besides, it’s quite possible that going to college is not the right choice for you.

D.During this time, the student can take a few inexpensive classes at a community college.E. So students take massive amounts of loans, which can take decades to pay off.

F. Many young people have other choices, like military service, work experience, community service or travel.

G. The transition from high school to college is an emotional challenge for almost everybody, especially if you move away from home.

单项选择题 A1型题