问题 单项选择题

某系统采用请求页式存储管理方案,假设某进程有6个页面,系统给该进程分配了4个存储块,其页面变换表如下表所示,表中的状态位等于I/O分别表示页面在内存/不在内存。当该进程访问的页面2不在内存时,应该淘汰表中页号为 (1) 的页面。假定页面大小为4K,逻辑地址为十六进制3C18H,该地址经过变换后的页帧号为 (2)

(2)处填()。

A.2

B.5

C.8

D.12

答案

参考答案:A

解析:

[分析]: 本题考查操作系统存储管理方面的基础知识。

在请求页式存储管理方案中,当访问的页面不在内存时需要置换页面,置换页面的原则如下表,即最先置换访问位和修改位为00的页,其次是访问位和修改位为01的页,然后是访问位和修改位为10的页,最后才置换访问位和修改位为11的页。因此本题当该进程访问的页面2不在内存时,应该淘汰表中页号为5的页面。

由于3C18H=3000+0C18,因此该地址对应的页号为3,根据页面变换表,经变换后的页帧号为2。

单项选择题
阅读理解

阅读理解。

     There were smiling children all the way. Charily they knew at what time the train passed their homes and

they made it their business to stand along the railway, wave to complete strangers and cheer them up as they

rushed towards Penang. Often whole families stood outside their homes and waved and smiled as if those on

the trains were their favorite relatives. This is the simple village people of Malaysia. I was moved.

     I had always traveled to Malaysia by plane or car, so this was the first time I was on a train. I did not

particularly relish the long train journey and had brought along a dozen magazines to read and reread. I looked

about the train. There was not one familiar face. I sighed and sat down to read my Economics.

     It was not long before the train was across the Causeway and in Malaysia. Johore Baru was just another

city like Singapore, so I was tired of looking at the crowds of people as they hurried past. As we went beyond

the city, I watched the straight rows of rubber trees and miles and miles of green. Then the first village came

into sight, Immediately I came alive; I decided to wave hack.

     From then on my journey became interesting. I threw my magazines into the waste basket and decided to

join in Malaysian life. Then everything came alive. The mountains seemed to speak to me. Even the trees were

smiling. I stared at everything as if I was looking at it for the first time.

     The day passed fast and I even forgot to have my lunch until I felt hungry. I looked at my watch and was

surprised that it was 3:00 pm. Soon the train pulled up at Butterworth. I looked at the people all around me.

They all looked beautiful. When my uncle arrived with a smile, I threw my arms around him to give him a

warm hug (拥抱). I had never done this before. He seemed surprised and then his weather-beaten face warmed

up with a huge smile. We walked arm in arm to his car.

     I looked forward to the return journey.

1. The author expected the train trip to be _____. [ ]

A. adventurous

B. pleasant

C. exciting

D. dull

2. What did the author remember most fondly of her train trip? [ ]

A. The friendly country people.

B. The mountains along the way.

C. The crowds of people in the streets.

D. The simple lunch served on the train.

3. What did the author remember most fondly of her train trip? [ ]

A. The friendly country people.

B. The mountains along the way.

C. The crowds of people in the streets.

D. The simple lunch served on the train.

4. Where was the writer going? [ ]

A. Johore Baru.

B. The Causeway.

C. Butterworth.

D. Singapore.

5. What can we learn from the story? [ ]

A. Comfort in traveling by train.

B. Pleasure of living in the country.

C. Reading gives people delight.

D. Smiles brighten people up.