操作系统复习题 (7)

Operating Systems, 5th ed. Test Bank Chapter 8

Chapter 8 – Virtual Memory

True / False Questions:

1. T / F – In a system employing a memory management strategy that doesn’t require an entire

process to be in main memory at one time, the portion of a process that is actually in main

memory at any given time is defined to be the resident set of the process. 在一个使用一个不需要整个的程序以一个次是在主存中的存储器管理系统中, 程序的部分实际上是在任何的给定时间是在主记忆中定义当程序的居留组。

ANS: T

2. T / F – The condition known as thrashing occurs when the majority of the processes in main

memory require repetitive blocking on a single shared I/O device in the system.在一个系统中，当大量的主存中的进程要求重复阻断一个单独共享的I/O设备的情况称之为系统抖动

ANS: F (processor spends most of its time swapping rather than executing) 错。是处理器花费大量时间不断进行交换块，而不是去执行指令

3. T / F – The modify (M) bit is a control bit in a page table entry that indicates whether the

contents of the corresponding page have been altered since the page was last loaded into memory.修改位（M）是一个控制位，他表示相应页的内容从上一次装入主存中到现在是否已经发生变化。

ANS: T对

4. T / F – A Page Fault occurs when the desired page table entry is not found in the Translation

Lookaside Buffer (TLB).一个页错误的发生是在转移后备缓冲器中不存在所需要的页

ANS: F (when the desired page is not found in main memory)错误，是发生在主存中不存在所需页表

5. T / F – One of the advantages to the programmer of virtual memory using segmentation is that it

simplifies the handling of growing data structures by allowing the segment to grow or shrink as

necessary.对程序员而言，使用虚拟内存的一个优点是它简化了处理增加的数据结构，这是通过允许段进行必要的增加或者缩小的操作

ANS: T对

6. T / F – In a combined paging/segmentation system, a user’s address space is broken up into a

number of fixed-size pages, which in turn are broken up into a number of segments.在一个段页复用的系统中，一个用户的地址空间被划分程序多固定大小的页，这些也有被划分成许多段

ANS: F (opposite – segments/pages)错误的，先分成段，在进行分页

7. T / F – To achieve sharing in a segmentation system, it is possible for a segment to be

referenced in the segment tables of more than one process. 为了实现在一个段系统的共享，一个段有可能再多共和进程的段表中被使用

Page of 8

1

Operating Systems, 5th ed.

ANS: T

Test Bank Chapter 8

8. T / F – Linux is an example of an operating system that does not provide virtual 就是一个没有提供虚拟内存的操作系统。

ANS: F (early UNIX or MS-DOS)错，早期的unix和ms－dos

9. T / F – The fetch policy determines when a page should be brought into main memory.读取策略确定一页何时取入主存

ANS: T对

10. T / F – The Least Recently Used (LRU) replacement policy replaces the page in memory that has

been referenced most 替换策略是替换最常用的页

ANS: F错 (that has not been referenced in the longest amount of time) .LRU替换策略是替换距离当前时间最远的页

11. T / F – A global replacement policy considers all unlocked pages in main memory as candidates

for replacement, regardless of which process owns a particular page.全局替换策略是把主存中所有的未被锁定的页都作为替换的候选页，而不管他们属于那个进程

ANS: T对

12. T / F – In a precleaning policy, modified pages are written to secondary memory once they have

been selected for replacement.在预约式清除策略中，被修改的页一旦被选中作为替换，将会被写入辅存中

ANS: F (written before that, so they can be batched)错

13. T / F – SVR4 and Solaris systems use two separate schemes for memory management, one for user

processes and disk I/O, and another for kernel memory 4和Solaris系统使用了两套独立的内存管理方案，一个是对用户进程和磁盘的I/O接口，而另一个则是为微内核内存分配管理

ANS: T

14. T / F – Linux makes use of a two-level page table structure, consisting of a page directory and

a page 利用两级分页结构组成页目录和页表

ANS: F (three-level, also a page middle directory)错误，应用了三级，还包括页中间目录

15. T / F – Every W2K user process sees a separate 32-bit address space, allowing 4 GB of memory

per process.每一个win2000的用户进程看到的是一个独立的32位地址空间，每个进程允许有4GB存储空间

ANS: T对

Page of 8

2

Operating Systems, 5th ed.

Multiple Choice Questions:

Test Bank Chapter 8

1. The type of memory that allows for very effective multiprogramming and relieves the user of

memory size constraints is referred to as:哪一种类型的存储器允许更有效的多道程序设计，并且解除了用户与主存大小之间的约束

a.

b.

c.

d.

ANS: B

2. The situation where the processor spends most of its time swapping process pieces rather than

executing instructions is called: 处理器花费大量时间不断进行交换块，而不是去执行指令的现象称为

a.

b.

c.

d.

ANS: C

3. The situation that occurs when the desired page table entry is not found in the Translation

Lookaside Buffer (TLB) is called a: 在转移后备缓冲器中不存在所需要的页的情况叫做

a.

b.

c.

d.

ANS: A

4. The real address of a word in memory is translated from the following portions of a virtual

address:一个字的在主存中的真实地址从下列虚拟地址的哪一部分转送的

a.

b.

c.

d.

ANS: B

5. Segmentation has a number of advantages to the programmer over a non-segmented address space,

including:分段组织和非段式地址空间想必有很多优点，包括

Page number and frame number页号和帧号

Page number and offset页号和偏移地址

Frame number and offset帧号和偏移地址

None of the above都不是

TLB miss TLB未命中

TLB hit TLB命中

Page fault 页错误

None of the above都不是

Paging分页

The Principle of Locality局部性原理

Thrashing系统抖动

None of the above都不是

Real memory真实内存

Virtual memory虚拟内存

Main memory主存

All of the above三者皆是

Page of 8

3

Operating Systems, 5th ed.

a.

b.

c.

d.

ANS: D

Test Bank Chapter 8

Simplifying the handling of growing data structures简化不断增长的数据结构的处理

Sharing among processes进程间的共享

Protection 保护机制

All of the above以上皆是

6. In a combined paging/segmentation system, a user’s address space is broken up into a number of:在一个段页结合的系统里，用户的地址空间被分成

a. Segments or pages, at the discretion of the programmer段或者页，根据程序员的想法

b. Fixed-size pages, which are in turn broken down into variable-sized segments固定的页，这些页被分成大小变化的段

c. Variable-sized Segments, which are in turn broken down into fixed-size pages 大小变化的段，，这些段有被分成大小固定的页

d. All of the above以上皆是

ANS: C

7. Sharing is achieved in a segmentation system by:分段系统实现共享是通过

a. Referencing a segment in the segment tables of more than one process再多个相关进程的段表中引用同一个段

b. Each process segment table having a reference to the dispatcher main memory area每一个进程的段表都涉及到主存区域的调度器

c. Having a common data area that all processes can share拥有一个所有进程都能共享的数据区

d. All of the above以上皆是

ANS: A

8. A fundamental choice in the design of the memory-management portion of an O/S is: 操作系统的内存管理设计的一个基本选择是

a. Whether or not to use virtual memory techniques 是否使用虚拟技术

b. Whether to use paging, segmentation of a combination of the two使用分页还是分段还是二者的组合

c. The algorithms employed for various aspects of memory management为各种存储管理特征采用的算法

d. All of the above以上皆是

ANS: D

9. The fetch policy that exploits the characteristics of most secondary memory devices, such as

disks, which have seek time and rotational latency is called:利用了大多数辅存设备的特性，这些设备有寻道时间和合理的延迟，这种读取策略

a. Demand paging 请求式分页

b. Prepaging 预约式分页

Page of 8

4

Operating Systems, 5th ed. Test Bank Chapter 8

c. Swapping 交换式分页

d. None of the above都不是

ANS: B

10. The replacement policy that is impossible to implement because it would require the O/S to have

perfect knowledge of future events is called the:由于要求操作系统必须知道将来的世界安而无法实现的替换策略是

a.

b.

c.

d.

ANS: A

11. The replacement policy that chooses only among the resident pages of the process that generated

the page fault in selecting a page to replace is referred to as a：仅仅在产生这次页错误的进程的驻留页中进行选择的替换策略是

a.

b.

c.

d.

ANS:

12. The concept associated with determining the number of processes that will be resident in main

memory is referred to as:与决定留在主存中进程数的概念是

a.

b.

c.

d.

ANS: C

13. In SVR4 and Solaris systems, the memory management scheme that manages user processes and disk

I/O is called the:在SVR4和Solaris系统中，对用户进程和磁盘I/O的内存管理方案是

a.

b.

c.

d.

ANS: A

Paging system 分页系统

Virtual memory manager虚拟内存管理

Kernel memory allocator内核内存分配器

None of the above都不是

A cleaning policy 清除策略

The page fault frequency页错误策略

Load Control加载控制

None of the above都不是

B

Global replacement policy 全局替换策略

Local replacement policy局部替换策略

Variable replacement policy可变替换策略

None of the above都不是

Optimal policy 最佳策略

Least recently used (LRU) policy最近最少使用策略

Clock policy时钟策略

None of the above都不是

Page of 8

5

Operating Systems, 5th ed. Test Bank Chapter 8

14. The multi-level memory management scheme implemented in Linux was designed to minimize large page

tables and directories in which of the following line of processors:适合于Linux中使用的多级内存管理系统

a.

b.

c.

d.

ANS: C

15. The Windows 2000 virtual memory manager can use page sizes ranging from:WIN2000中使用的页尺寸的范围是

a. 4 KB to 64 KB

b. 64 KB to 4 GB

c. 4 GB to 4 TB

d. None of the above都不是

ANS: A

Fill-In-The-Blank Questions:

I

1. n a system employing a memory management strategy that doesn’t require an entire process to be

in main memory at one time, the portion of a process that is actually in main memory at any

given time is defined to be the _______________ of the process. 在一个使用不需要整个进程都在中的存储器管理的系统中,进程执中的任何时候都在主存中的部分被定义为常驻集

ANS: resident set

2. The situation where the processor spends most of its time swapping process pieces rather than

executing instructions is called _______________.处理器的大部分时间都在进行交换块，而没有去执行指令的情况被称为系统抖动

ANS: thrashing

3. Most virtual memory schemes make use of a special high-speed cache for page table entries,

called a _______________. 大部分虚拟内存机制为页表项使用了一种特殊的高速缓存，被叫做转移后备缓冲器

ANS: translation lookaside buffer (TLB)

4. Each entry in a _______________ contains control bits and the corresponding frame number if the

page is resident in memory. 如果页在主存的时候，每一个页表项包含控制位和与之相对应的帧号

ANS: page table

16-bit X86 architecture

32-bit Pentium/X86 architecture

64-bit Alpha architecture

None of the above都不是

Page of 8

6

Operating Systems, 5th ed. Test Bank Chapter 8

5. In a segmentation system, each entry in a _______________ contains control bits and the starting

address and the length of the segment. 在一个分段系统中，每一个段表项 包含控制位和段的起始地址及长度

ANS: segment table

6. ______________, which is transparent to the programmer, eliminates external fragmentation,

provides efficient use of main memory, and has pieces of fixed, equal size. 分页机制对程序员来说可以除去外部碎片，提高主存使用效率，它的大小是固定和相等的

ANS: paging

7. ______________, which is visible to the programmer, has the ability to handle growing data

structures, modularity, and support for sharing and protection. 分段机制对程序员而言，是可见的，它能够简化不断增长的数据结构的处理，模块化，支持共享以及保护机制

ANS: segmentation

8. An example of an O/S that doesn’t provide virtual memory is _______________. 不提供虚拟内存的操作系统的例子是MS-DOS或者早期的UNIX

ANS: MS-DOS or early UNIX

9. The fetch policy where a page is brought into main memory only if a reference is made to a

location on that page is called _______________. 只有当访问到某页中的一个单元时才将该页取入主存的读取策略是请求式分页

ANS:

10. The replacement policy that treats the page frames allocated to a process as a circular buffer

is called _______________. 替换策略中把分配给进程的页帧看作是一个循环缓冲区的策略是FIFO

ANS: FIFO

11. A _______________ replacement policy chooses only among the resident ages of the process that

generated the page fault in selecting a page to replace. 仅仅在产生这次页错误的进程驻留页中选择的替换策略是局部替换

ANS: local

12. A _______________ policy writes modified pages before their page frames are needed so that pages

can be written out in batches. 将被修改的多个页在需要用到它们所占据的页帧之前成批的写回辅存的清除策略是预约式清除

ANS: precleaning

demand paging

Page of 8

7

Operating Systems, 5th ed. Test Bank Chapter 8

13. In SVR4 and Solaris systems, the memory management scheme that manages memory allocation for the

kernel is called the _________________________ . 在SVR4和Solaris系统中，为内核分配内存的内存管理机制是内核内存分配器

ANS: kernel memory allocator

14. Linux systems use a ___________-level page table structure in its memory management scheme to

accommodate large 系统在它的内存管理机制中使用三级页表结构来处理比较大的地址

ANS: three

15. In a W2K system, although each user sees a 32-bit address space, allowing 4 GB of memory per

process, a portion of this memory is reserved for O/S use, so a user process actually has access

to ___________ of virtual address space. 在win2000系统中，尽管每一个用户看到一个32位地址空间，允许每个进程有4GB，但是一部分存储空间默认为操作系统，因此每个用户事实上只能使用2GB的虚拟地址空间

ANS: 2 GB

Page of 8

8