Worksheetsosg202
Total questions: 101
Worksheet time: 51mins
Name
Class
Date
1.
Which is a advantage of implementing threads in the kernel? *
a)
None of the other choices
b)
Is good for multiprocessor architecture and if one thread is blocked does not cause the other thread to be blocked
c)
If one thread is blocked does not cause the other thread to be blocked
d)
Is good for multiprocessor architecture
2.
Critical Region (Section) concept used in interprocess communication is: *
a)
A part of shared memory
b)
None of the other choices
c)
A part of the program where the shared memory is accessed
d)
A part of shared data
3.
OS Win32 use system call_____, while OS Unix use system call______ to create a new process *
a)
fork, CreateProcess
b)
CreateProcess; fork
c)
copy, CreateProcess
d)
CreateProcess; copy
4.
Which statement about disabling interrupts to resolve race conditions is wrong? *
a)
Disabling/enabling interrupts may negatively affect the I/O system
b)
User-mode programs are the best place to invoke disableInterrupt()
c)
In theory, a program can disable interrupts when it enters a critical section, and re-enable interrupts when finished with a critical section, to eliminate race conditions
d)
Programs with infinite loops in their critical sections are a significant problem with the interrupt-based approach
5.
Which of the events that causes the processes to be created, when an operation system is booted? *
a)
System initialization
b)
Execution of a process creation system call
c)
User request to create a new process
d)
Initiation of a batch job
6.
Which of the following process state transitions is legal? *
a)
Blocked (waiting) -> running
b)
Ready -> Blocked (waiting)
c)
None of the other choices
d)
Running -> ready
7.
Which of the following process state transitions is correct, when the external event for which a process was waiting happens? *
a)
Running -> Blocked (waiting)
b)
Running -> ready
c)
Ready -> running
d)
Blocked (waiting) -> ready
8.
Which of the following process state transitions is correct, when the operating system discovers that process can not continue right now because of is not enough resource? *
a)
Running -> ready
b)
Blocked (waiting) -> ready
c)
Ready -> running
d)
Running -> Blocked (waiting)
9.
Which of the following statements about semaphores is true? *
a)
If several processes attempt a P(S) operation simultaneously, only one process should be allowed to proceed.
b)
A semaphore implementation should guarantee that processes do not suffer indefinite postponement.
c)
All of the other choices
d)
P and V (Down and Up) operations should be indivisible operations
10.
Which of the following conditions must be held to provide good solution for mutual exclusion? *
a)
No process running outside its critical region may block another process
b)
No process must wait forever to enter its critical region
c)
No two processes simultaneously in critical region
d)
All of the other choices
e)
No assumptions made about speeds or numbers of CPUs
11.
In terms of disk storage efficiency, the method of "Backing up pages dynamically" in comparison with the method of "Paging to a static swap area" is *
a)
Nearly equal
b)
Better
c)
Equal
d)
Worse
12.
A well-known operating system for Handheld Computer is: *
a)
e-COS
b)
TinyOS
c)
Symbian OS and Palm OS
d)
MS-DOS
13.
Critical Region (Section) concept used in interprocess communication is: *
a)
None of the other choices
b)
A part of shared data
c)
A part of shared memory
d)
A part of the program where the shared memory is accessed
14.
When there is an excessive amount of page swapping between main memory and secondary storage, the operation becomes inefficient, which is called ____. *
a)
excessive demand paging
b)
over swapping
c)
hot swapping
d)
thrashing
15.
Suppose a virtual address space of 2^24 words and the page size is 2^12 words. If the virtual address is 123456 in Hexadecimal, what would be the page number in Hexadecimal? *
a)
12345
b)
1234
c)
123456
d)
123
16.
A system with 32 bit virtual address. If the page size is 4 KB and each table entry occupies 4 bytes, what is the size of the page table? *
a)
4 MB
b)
8 MB
c)
2 MB
d)
1 MB
17.
Which of these statements about the Inverted Page Table are true? *
a)
An entry contains the pair (process, offset) mapped into the corresponding page frame
b)
An entry contains the pair (segment, virtual page) mapped into the corresponding page frame
c)
An entry contains the pair (process, virtual page) mapped into the corresponding page frame
d)
An entry contains the pair (segment, offset) mapped into the corresponding page frame
18.
In terms of speed the best method of Dynamic Storage-Allocation is: *
a)
Worst fit
b)
Best fit
c)
Next fit
d)
First fit
19.
A process where no concurrency inside process; everything happens sequentially is called : *
a)
None of the other choices
b)
Sequential access process
c)
Sequential process
d)
Random access process
20.
What is not a field in the process table that relates process management? *
a)
CPU time used
b)
PC, PSW, SP
c)
User ID, Group ID
d)
Process ID
21.
Which of the following process state transitions is correct, when the external event for which a process was waiting happens? *
a)
Ready -> running
b)
Running -> Blocked (waiting)
c)
Blocked (waiting) -> ready
d)
Running -> ready
22.
Which is the maximum partition size, if the FAT type is FAT-32 and the block size is 4 KB? *
a)
256 MB
b)
1 TB
c)
512 MB
d)
128 MB
23.
Where should be put the page replacement algorithm In Mach model of Page fault handling with an external pager? *
a)
In the page fault handler that is part of the kernel
b)
In the external pager running in user space
c)
All of the other choices
d)
In the low-level MMU handler
24.
Consider a computer system that has cache memory, main memory (RAM) and disk, and OS uses virtual memory. It takes 1 nsec to access a byte from the cache, 10 nsec to access a byte from RAM, and 5 msec to access a block of 1000 bytes from the disk. If a book has 1000 pages, each with 25 lines of 80 characters each, How long it will take to electronically scan the text for the case of the master copy being in each of the level as one proceeds down the memory hierarchy (from inboard memory to offline storage)? *
a)
4 msec, 40 msec, 20 sec
b)
1 msec, 10 msec, 5 sec
c)
2 msec, 20 msec, 10 sec
d)
1 msec, 10 msec, 10 sec
25.
What is correct about trap instructions and interrupts? *
a)
An interrupt is caused by an external event
b)
Trap instruction switches the execution mode of a CPU from the user mode to the kernel mode.
c)
A trap instruction is caused by a user program to invoke functions in the OS kernel
d)
All of the other choices
26.
Which of the following operating system has the concept of a process hierarchy? *
a)
Win32
b)
CP/M
c)
Unix
d)
MS-DOS
27.
As one proceeds down the memory hierarchy (from inboard memory to offline storage), which of the following conditions is correct? *
a)
Decreasing access time
b)
Increasing capacity
c)
Increasing cost per bit
d)
None of the other choices
28.
Assume that the Page Table below is in effect: Page Number: 0 1 2 3; Page Frame Number: 8 10 5 11. The number of lines per page is 400. The actual memory location for line 1634 is ____. *
a)
None of the other choices
b)
1634
c)
3
d)
4434
29.
How many percent of the CPU time is wasted, when a computer system has enough room to hold two program and these programs are idle waiting for I/O half the time? *
a)
25%
b)
75%
c)
None of the other choices
d)
50%
30.
Working set model is used for: *
a)
Determining whether page replacement is needed
b)
Finding the average number of frames a job will need to run smoothly
c)
All of the other choices
d)
Finding the minimum number of frames necessary for a job so that jobs can be run without "thrashing"
31.
An arrival message causes the system to create a new thread to handle this message. This new thread is call______ *
a)
Activator
b)
Upcall
c)
Pop-up
d)
Distributed
32.
What is Higher-level proposal in the solution of Mutual exclusion and Synchronization? *
a)
Monitors
b)
Message passing
c)
Disable Interrupts
d)
Peterson's Solution
33.
What is the characteristic of the second generation of operating system? *
a)
ICs and multiprogramming
b)
Transistors, batch systems
c)
Vacuum tubes, plug boards
d)
Personal computers, single user, multitasking
34.
What is the main characteristic of real-time operating system? *
a)
Multiple CPU
b)
Time-sharing
c)
Time is key parameter
d)
Many I/O devices
35.
LRU replaces the page that has spent the *
a)
longest time in memory
b)
shortest time in memory
c)
longest time in memory without being referenced
d)
shortest time in memory without being referenced
36.
Which of the following is not correct about user-level threads? *
a)
User-level threads are more efficient than kernel threads, in the sense that they do not need kernel calls to switch among threads
b)
With user-level threads, customized scheduling algorithms cannot be implemented
c)
User-level threads cannot be preempted by clock interrupts unless the whole process' quantum has been used up
d)
If one user-level thread makes a blocking system call, the system will block the entire process (which contains that user-level thread)
37.
A computer has four page frames. The time of loading, time of last access, and the R and M bits for each page are as shown below (the times are in clock ticks). Which page will NRU replace?
a)
0
b)
1
c)
2
d)
3
38.
A computer with a 32-bit address uses a two-level page table. Virtual addresses are split into a 9-bit top-level page table field, an 11-bit second-level page table field, and an offset. How many pages are there in the address space? *
a)
2^23 pages
b)
2^20 pages
c)
2^22 pages
d)
2^21 pages
39.
Which is not true about "Backing up pages dynamically"? *
a)
Requires a disk map in memory
b)
Pages do not have fixed swap area on the disk
c)
When a page is swapped out, an empty disk page is chosen on the fly and disk map is updated accordingly
d)
Needs less main memory than the method "Paging to a static swap area"
40.
What is not the technique of implementation for Virtual Memory? *
a)
Partition
b)
Segmentation
c)
Paging
d)
All of the other choices
41.
As one proceeds down the memory hierarchy (from inboard memory to offline storage), which of the following conditions is correct? *
a)
None of the other choices
b)
Decreasing cost per bit
c)
Decreasing access time
d)
Decreasing capacity
42.
Which of the following actions generates an external interrupt? *
a)
A page that does not exist in the main memory is accessed by the virtual storage management.
b)
A system call instruction is executed.
c)
Division by zero occurs.
d)
An input/output operation is completed.
43.
Which is not true about the method of backing store: "Paging to a static swap area"? *
a)
The swap area on the disk is as large as the process virtual address space
b)
Calculating the address in swap area requires knowing only where the process' paging area begins
c)
A page that is in memory always have shadow copy on disk
d)
Requires a disk map in memory
44.
The page size that is too small will generate ____ *
a)
More difficult to calculate actual position
b)
Very long Page tables
c)
Excessive internal fragmentation
d)
Excessive external fragmentation
45.
Assume jobs A-D arrive in quick succession in the READY queue. Using round robin scheduling (quantum=4), the turnaround time for job B is ____. Arrival time: 0 1 2 3; Job: A B C D; CPU cycle: 8 4 9 5 *
a)
24
b)
20
c)
22
d)
7
46.
Which of the following is true about Atomic action on semaphores? *
a)
Changing the value
b)
Possibly going to sleep
c)
Checking the value
d)
All of the other choices
47.
Which of the following statements is a hardware solution to the critical region problem? *
a)
None of the other choices
b)
Semaphore
c)
Shared memory
d)
TSL
48.
Five batch jobs A through E, arrive at a computer center at almost the same time. They have estimated running times of 8, 6, 2, 10, and 4 minutes. Their (externally determined) priorities are 3, 5, 2, 1, and 4, respectively, with 5 being the highest priority. Determine the average waiting time for Priority scheduling. Ignore process switching overhead. *
a)
12,8 minutes
b)
10,8 minutes
c)
54 minutes
d)
16,8 minutes
49.
If there are 128 pages and the page size is 32 K words, what is the length of logical address? *
a)
24 bits
b)
26 bits
c)
30 bits
d)
22 bits
50.
Which of the following information bits in the entry of page table is used to indicate locked page? *
a)
Modified bit
b)
Caching disabled
c)
Present/absent bit
d)
Referenced bit
51.
The modified/dirty bit is used for the purpose of: *
a)
Dynamic allocation of memory used by one process to another
b)
Reduce the average time required to service page faults
c)
None of the other choices
d)
Implementing FIFO page replacement algorithm
52.
What is not a main function of an operating system? *
a)
Manage the I/O devices
b)
Provide the users with an extended (virtual) machine
c)
Provide user interfaces
d)
Support virtual memory
53.
Which of following statements about the memory hierarchy is false? *
a)
Gigabytes of slow cheap disk storage
b)
None of the other choices
c)
Some medium-speed medium price main memory
d)
Small amount of fast expensive memory-cache
54.
A simple structuring model for monolithic system includes: *
a)
All of the other choices
b)
A main program that invokes the requested service procedure
c)
A set of service procedures that carry out the system calls
d)
A set of utility procedures that help the service procedures
55.
Which kind of tables is used in the segmentation? *
a)
Local Descriptor Table (LDT )
b)
None of the other choices
c)
Both Global Descriptor Table (GDT) and Local Descriptor Table (LDT )
d)
Global Descriptor Table (GDT)
56.
Consider a swapping system in which the memory consists of the following hole sizes: 10K, 4K, 20K, 15K, 9K. Assume best fit algorithm is used. Which holes are taken for successive segment requests of 8K, 12K, 10K? *
a)
10K, 15K, 20K
b)
10K, 20K, 15K
c)
20K, 15K, 10K
d)
9K, 15K, 10K
57.
In some thread systems, a thread want be blocked until an other thread has exited. It can establish this goal by calling______ *
a)
thread_yield
b)
thread_wait
c)
thread_create
d)
thread_exit
58.
Consider a computer system that has cache memory, main memory (RAM) and disk, and OS uses virtual memory. It takes 1 nsec to access a byte from the cache, 10 nsec to access a byte from RAM, and 5 msec to access a block of 1000 bytes from the disk. If a book has 1000 pages, each with 50 lines of 80 characters each, How long it will take to electronically scan the text for the case of the master copy being in each of the level as one proceeds down the memory hierarchy (from inboard memory to offline storage)? *
a)
4 msec, 40 msec, 20 sec
b)
1 msec, 10 msec, 10 sec
c)
2 msec, 20 msec, 10 sec
d)
1 msec, 10 msec, 5 sec
59.
Which of the following is a preemptive scheduling algorithm *
a)
Round Robin
b)
None of the other choices
c)
Shortest Job First
d)
FCFS
60.
Which of the following instructions should be allowed in user mode? *
a)
Disable all interrupts
b)
Read the time-of-day clock
c)
Change the memory map
d)
Set the time-of-day clock
61.
Examples of general purpose stored program computers include the following except *
a)
Network servers
b)
Workstations
c)
MP3 player
d)
Personal computers
62.
When a virtual memory system manages memory in fixed length units, which of the following terms correctly represents its unit? *
a)
Segment
b)
Block
c)
Frame
d)
Page
63.
At which level in Protection Rings on the Pentium the System calls reside *
a)
0
b)
2
c)
1
d)
3
64.
The Mach model of Page fault handling with an external pager includes *
a)
All of the other choices
b)
An external pager running in user space
c)
A low-level MMU handler
d)
A page fault handler that is part of the kernel
65.
Which of the following information bits in the entry of page table is used to indicate that page is changed since it was loaded in memory? *
a)
Modified bit
b)
Status bit
c)
Present/absent bit
d)
Referenced bit
66.
Which strategy is a simplest design for speeding up Paging? *
a)
Page table is loaded into TLB
b)
Page table is loaded into main memory
c)
Page table is loaded into registers
d)
Page table is loaded into disk
67.
How many level of scheduling are used in computer *
a)
2
b)
4
c)
3
d)
1
68.
If there are 256 pages and the page size is 4K words, what is the length of logical address? *
a)
20 bits
b)
14 bits
c)
17 bits
d)
15 bits
69.
Which of the following is not correct about hard links? *
a)
Hard links require to increase the link count in the i-node for each linking
b)
Hard links can point to files in the network
c)
Hard links do not require extra disk space
d)
Hard links can only point to files on the same machines
70.
____ is a specialized WRITE command for existing data files that allows for adding records to end of the file. *
a)
UPDATE
b)
REWRITE
c)
APPEND
d)
MODIFY
71.
Which of the following is correct about symbolic links? *
a)
Symbolic links need not space to store the name and the file pointed to
b)
Symbolic links can only point to files on the same machines
c)
Symbolic links can point to files in the network
d)
None of the other choices
72.
The primary disadvantage of contiguous storage is that ____. *
a)
It is difficult to find information in files
b)
It is hard to implement and manage
c)
File can't be expanded unless there is empty space available immediately following it
d)
It is an inefficient use of space
73.
Which solution is used to solve the "missing block" problem in file system consistency? *
a)
The file system checker adds the missing blocks to the free list
b)
The file system checker rebuilds the free list
c)
The file system checker allocate the free block, then copy the duplicate block in used to there
d)
None of the other choices
74.
A ____ is a group of related records that contains information to be used by specific application programs to generate reports. *
a)
Record group
b)
Field
c)
Directory
d)
File
75.
A directory in UNIX/Linux consists of the following *
a)
None of the other choices
b)
File name, file size, location of the file on disk, date created, owner ID
c)
Inode number and file name
d)
File name, file size, location of the file on disk
76.
Which of the following is not a well-known technique for organizing the physical storage blocks for a file? *
a)
Contiguous block allocation
b)
Linked list block allocation
c)
Sparse block allocation
d)
Indexed block allocation
77.
____ allocation allows files to use any storage space available on the disk. *
a)
Noncontiguous storage
b)
Add-on storage
c)
Contiguous storage
d)
Fragmented storage
78.
What is incorrect about contiguous allocation of files? *
a)
It leads to excellent read performance
b)
It is simple to implement
c)
It is widely used on CD-ROMs
d)
It does not cause disk fragmentation
79.
Which of the following is not file structure? *
a)
Byte sequence
b)
Record sequence
c)
Ring
d)
Tree
80.
____ is a specialized WRITE command for existing data files that allows for appending records or for rewriting selected records in their original place in the file. *
a)
REWRITE
b)
UPDATE
c)
APPEND
d)
MODIFY
81.
How many is maximum number of partition that most disk can be divided up into? *
a)
4
b)
3
c)
5
d)
2
82.
The disk block in a partition that includes a magic number, the number of blocks in the file system and other key administrative information is called: *
a)
Superblock
b)
MBR
c)
Free block
d)
Boot block
83.
Which of the following is not special file? *
a)
Block special file
b)
Character special file
c)
None of the other choices
d)
Stream special file
84.
Which of the following is true about the block size in disk space management *
a)
the larger the block size is the worse the disk space utilization is
b)
the larger the block size is the lower the data rate is
c)
the larger the block size is lesser the disk space is
d)
None of the other choices
85.
The absolute pathname of a file in Linux is with respect to the *
a)
Login directory
b)
Root directory on the system
c)
Home directory
d)
All of the other choices
86.
Which is the maximum partition size, if the FAT type is FAT-16 and the block size is 2 KB? *
a)
256 MB
b)
512 MB
c)
8 MB
d)
128 MB
87.
Which of a system callI is to allow the file to appear in more than one directory? *
a)
OPEN
b)
CREATE
c)
LINK
d)
SEEK
88.
____ are special files with listings of filenames and their attributes. *
a)
Databases
b)
Programs
c)
Data files
d)
Directories
89.
How large is the block size, if the maximum partition size is 128 MB and the FAT type is FAT-16? *
a)
8 KB
b)
2 KB
c)
1 KB
d)
4 KB
90.
The disk blocks in a partition that contains the top of the file system tree is called: *
a)
Free space management blocks
b)
Superblock
c)
Root directory
d)
Boot block
91.
The special files are: *
a)
none of the other choices
b)
character special file and block special file
c)
character special file
d)
block special file
92.
Which of a system callI is to allow the system free up internal table space? *
a)
OPEN
b)
DELETE
c)
SEEK
d)
CLOSE
93.
Which method is used to implement files to keep each file as a linked list of disk blocks? *
a)
File Allocation Table
b)
Linked List Allocation
c)
i-node
d)
Contiguous Allocation
94.
Which of the following is not correct about hard links and symbolic links? *
a)
Hard links can point to files on other machines
b)
Hard links do not require extra disk space
c)
Symbolic links need space to store the name and the file pointed to
d)
Symbolic links can point to files in the network
95.
Which are allocation methods of disk blocks for files: *
a)
Contiguous allocation
b)
All of the other choices
c)
Indexed allocation
d)
Linked allocation
96.
How large is the block size, if the maximum partition size is 8 MB and the FAT type is FAT-12? *
a)
1 KB
b)
8 KB
c)
2 KB
d)
4 KB
97.
Increasing file system performance is implemented by _____ *
a)
Block Read Ahead
b)
All of the other choices
c)
Defragmenting Disks
d)
Buffer cache
98.
Which of a system callI is to allow the system fetch the attributes and list of disk addresses into main memory for rapid access on later call? *
a)
RENAME
b)
CLOSE
c)
OPEN
d)
SEEK
99.
The File Manager writes the volume name and other descriptive information on an easy-to-access place on each unit: ____ of the magnetic disk *
a)
the innermost part
b)
the outermost part
c)
stored at the beginning of the volume
d)
immediately following the master file directory
100.
Strategy used for dumping a disk to tapes is: *
a)
Physical dump and Logical dump
b)
Physical dump
c)
None of the other choices
d)
Logical dump
101.
Which of the following information contain in the entry of the partition tables ? *
a)
Starting and ending address of each partition
b)
None of the other choices
c)
Marking a partittion as active
d)
Starting and ending address of each partition and Marking a partittion as active
100 %
