Quizzes 4, 5, 6

Question 1

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

Answer 1

inverted

Question 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

Answer 2

best fit

Question 3

How many page table for the whole OS?

Answer 3

one for each process

Question 4

T/F:

TLB is a special hardware to speed up page table search.

Answer 4

T

Question 5

T/F:

There is a separate TLB for each process.

Answer 5

F

Question 6

T/F:

Segmentation memory management is much faster than paging memory management.

Answer 6

F

Question 7

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

Answer 7

2

Question 8

The leftover hole in segmentation memory management is called

Answer 8

external fragmentation

Question 9

The leftover within a page is called

Answer 9

internal Fragmentation

Question 10

T/F:

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

Answer 10

F

Question 11

A RAID structure is ___

Answer 11

primarily used to ensure higher data reliability

Question 12

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

Answer 12

memory-management-unit (MMU)

Question 13

T/F:

The allocated portions of memory using a buddy system are all the same size.

Answer 13

F

Question 14

T/F:

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

Answer 14

F

Question 15

T/F:

Increase page size will increase the chance of TLB hit.

Answer 15

T

Question 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

Answer 16

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

Question 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

Answer 17

contiguous allocation

Question 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.

Answer 18

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

Question 19

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

Answer 19

spool

Question 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

Answer 20

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

Question 21

Direct memory access is a technique that___

Answer 21

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

Question 22

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

Answer 22

device queue

Question 23

T/F:

Starvation may occur in the FCFS disk-scheduling discipline.

Answer 23

F

Question 24

T/F:

In symbolic link, two i-nodes will be created for a file.

Answer 24

F

Question 25

T/F:

SSDs often use an FCFS disk-scheduling algorithm.

Answer 25

T