Quizzes 4, 5, 6 Flashcards Preview

OS Final Exam > Quizzes 4, 5, 6 > Flashcards

Flashcards in Quizzes 4, 5, 6 Deck (25)
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1

A(n) ____ page table has one page entry for each real frame of memory.

inverted

2

Which of the following dynamic storage-allocation algorithms results in the smallest leftover hole in memory?

best fit, worst fit, first fit, none of them

best fit

3

How many page table for the whole OS?

one for each process

4

T/F:
TLB is a special hardware to speed up page table search.

T

5

T/F:
There is a separate TLB for each process.

F

6

T/F:
Segmentation memory management is much faster than paging memory management.

F

7

Without TLB, for each memory address, considering page table, how many times do we need to really access memory?

2

8

The leftover hole in segmentation memory management is called

external fragmentation

9

The leftover within a page is called

internal Fragmentation

10

T/F:
When page fault happens, if there is no free frame available, the OS will report an error.

F

11

A RAID structure is ___

primarily used to ensure higher data reliability

12

The mapping of a logical address to a physical address is done in hardware by the ______.

memory-management-unit (MMU)

13

T/F:
The allocated portions of memory using a buddy system are all the same size.

F

14

T/F:
If the page-fault rate is too high, the process may have too many frames.

F

15

T/F:
Increase page size will increase the chance of TLB hit.

T

16

The free-space list can be implemented using a bit vector approach. Which of the following is a drawback of this technique?

This technique is not feasible for small disks.
It is not feasible to keep the entire list in main memory for large disks
The technique is more complicated than most other techniques.
To traverse the list, each block must be read on the disk

It is not feasible to keep the entire list in main memory for large disks

17

Which of the following allocation methods ensures that only one access is needed to get a disk block using direct access?

contiguous allocation
indexed allocation
linked allocation
hashed allocation

contiguous allocation

18

In an environment where several processes may open the same file at the same time, which one is true?

the operating system typically uses two internal tables called the system-wide and per-process tables to keep track of open files.
the operating system typically uses two internal tables called the system-wide and per-disk tables to keep track of open files.
the operating system typically uses three internal tables called the system-wide, per-disk, and per-partition tables to keep track of open files.
the operating system typically uses only one internal table to keep track of open files.

the operating system typically uses two internal tables called the system-wide and per-process tables to keep track of open files.

19

A(n) ____ is a buffer that holds output for a device that cannot accept interleaved data streams.

spool

20

Which of the following is a principle that can improve the efficiency of I/O and reduce CPU usage?

Move processing primitives into hardware, e.g., DMA
Decrease concurrency using DMA controllers
Increase the number of context switches.
Use small data transfers

Move processing primitives into hardware, e.g., DMA

21

Direct memory access is a technique that___

enables the associated controller to read and write data directly from/to primary memory with no CPU intervention during data transfer.

22

The list of processes waiting for a particular I/O device is called a(n) ____.

device queue

23

T/F:
Starvation may occur in the FCFS disk-scheduling discipline.

F

24

T/F:
In symbolic link, two i-nodes will be created for a file.

F

25

T/F:
SSDs often use an FCFS disk-scheduling algorithm.

T