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n1
When a reference occurs to a page that is not in memory called?
1) API
2) host
3) Page Fault
4) Digital Certificate
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12:06 PM
Score
1
/ 1(graded bySarah North)
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Question 2
When clusters are scattered around the disk is?
1) Race Condition
2) Parallel Computing
3) Interrupt
4) Fragmentation
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12:06 PM
Score
1
/ 1(graded bySarah North)
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Question 3
Causes a temporary halt to the normal execution of a program is refer to?
1) The Kernel
2) Ethernet
3) Interrupt
4) Starvation
Save Time
10:26 AM
Score
1
/ 1(graded bySarah North)
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Question 4
System Call Interface are called API
1) True
2) False
Save Time
10:27 AM
Score
0
/ 1(graded bySarah North)
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Question 5
A Bus Topology is most widely used network with?
1) The Kernel
2) Ethernet
3) Interrupt
4) Starvation
Save Time
10:27 AM
Score
1
/ 1(graded bySarah North)
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Question 6
When processes are not synchronized and they attempt to access and manipulate the same
data item
1) Race Condition
2) Parallel Computing
3) Interrupt
4) Fragmentation
Save Time
10:28 AM
Score
1
/ 1(graded bySarah North)
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Question 7
A High Level Protocol
1) TCP-IP
2) HTTP
3) MAC
4) NIC
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10:28 AM
Score
0
/ 1(graded bySarah North)
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Question 8
The core OS processes that must always be resident in memory
1) The Kernel
2) Ethernet
3) Interrupt
4) Starvation
Save Time
10:29 AM
Score
1
/ 1(graded bySarah North)
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Question 9
Every Ethernet device has a unique _________ address.
1) IP
2) MAC
3) broadcast
4) ARP
Save Time
10:29 AM
Score
1
/ 1(graded bySarah North)
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Question 10
Which of the following layers of a communications network in the OSI protocol is used
to handle frames, or fixed-length parts of packets?
1) network layer
2) physical layer
3) data-link layer
4) transport layer
Save Time
10:31 AM
Score
1
/ 1(graded bySarah North)
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Question 11
When indefinite waiting causes a low-priority process to never execute
1) The Kernel
2) Ethernet
3) Interrupt
4) Starvation
Save Time
10:31 AM
Score
1
/ 1(graded bySarah North)
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Question 12
Number of jobs completed in some specified time interval
1) Throughput
2) Waiting Time
3) Turnaround Time
4) Round Robin
Save Time
10:32 AM
Score
1
/ 1(graded bySarah North)
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Question 13
Identifies the author of a signed component that provides comprehensive support for the
authentication is?
1) PKI
2) Digital Certificate
3) Third-Party developer
4) All of the above
Save Time
10:32 AM
Score
1
/ 1(graded bySarah North)
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Question 14
A program that appears to be legitimate, but that is designed to actually behave in an
illegitimate manor called?
1) Virus
2) Worm
3) Trojan Horse
4) Code Red
Save Time
10:32 AM
Score
1
/ 1(graded bySarah North)
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Question 15
Combining processors together to improve system performance is:
1) Distrubuted Systems
2) Parallel Computing
3) Context Switch
4) Virtual Systems
Save Time
10:33 AM
Score
1
/ 1(graded bySarah North)
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Question 16
Saving the state of the current process and loading the state of a new process refer to?
1) Distrubuted Systems
2) Parallel Computing
3) Context Switch
4) Virtual Systems
Save Time
12:06 PM
Score
1
/ 1(graded bySarah North)
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Question 17
The Operating System is software that provides other software access to the hardware?
1) True
2) False
Save Time
10:36 AM
Score
1
/ 1(graded bySarah North)
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Question 18
What type of time is Context Switch Time?
1) Virtual Time
2) Throughput Time
3) Overhead Time
4) Deadlock Time
Save Time
10:40 AM
Score
1
/ 1(graded bySarah North)
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Question 19
Which of the following is true?
1) The interarrival period is the reciprocal (1 divided by) of the arrival rate
2) Fairness is not one of the performance metrics
3) Average turnaround time is not one of the performance metrics
4) A stochastic model does not involve random variables
Save Time
10:42 AM
Score
0
/ 1(graded bySarah North)
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Question 20
Which of the following scheduling algorithms requires knowing or estimating the length
of the next CPU burst?
1) FCFS
2) SPN
3) RR
4) LRU
Save Time
10:45 AM
Score
0
/ 1(graded bySarah North)
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Question 21
Which of the following is the appropriate one to use when you require only mutually
exclusive access to a resource?
1) Binary Semaphore
2) Counting Semaphore
3) Mutual Exclusion
4) Cirtical Sections
Save Time
10:47 AM
Score
0
/ 1(graded bySarah North)
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Question 22
Which of the following is not a Directory function?
1) Search for a file
2) Delete a file
3) Rename a file
4) Defragment a file
Save Time
10:48 AM
Score
1
/ 1(graded bySarah North)
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Question 23
In the Scheduling of Disk I/O request, what is there a tradeoff between?
1) Seek Time and Latency Time
2) Buffering and Caching
3) Input and Output
4) Throughput and Fairness
Save Time
10:48 AM
Score
0
/ 1(graded bySarah North)
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Question 24
Which of the following is not true about Paging?
1) The OS keeps track of all free frames
2) The OS is involved in converting logical to physical addresses
3) The OS makes sure the pages used by a process are all contiguous
4) The OS manages a page table
Save Time
10:52 AM
Score
0
/ 1(graded bySarah North)
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Question 25
Which type of file access permission scheme is used by Linux and Unix?
1) Attribute scheme
2) Access Control List
3) Encryption
4) Digital Signatures
Save Time
10:53 AM
Score
0
/ 1(graded bySarah North)
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Question 26
Which of the following is not one of the OSI layers?
1) Network Layer
2) Session Layer
3) Transport Layer
4) Security Layer
Save Time
10:53 AM
Score
1
/ 1(graded bySarah North)
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Question 27
Does the following Allocation Graph display a deadlocked state?
1) Deadlocked
2) Not Deadlocked
Save Time
11:00 AM
Score
1
/ 1(graded bySarah North)
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Question 28
What does the following reveal about processes P2, P5 and P6?
1) That each process is using Non-Contiguous Memory Allocation
2) That each process has External Fragmentation
3) That each process has Internal Fragmentation
4) None of the above
Save Time
11:03 AM
Score
0
/ 1(graded bySarah North)
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Question 29
True or False: Buffering or Caching I/O requests improves performance?
1) True
2) False
Save Time
11:04 AM
Score
1
/ 1(graded bySarah North)
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Question 30
Which of the following is not one of the purposes of Disk Scheduling?
1) Ensure Fairness
2) Decide when to process on I/O request
3) Manage requests from an I/O Queue
Save Time
11:05 AM
Score
1
/ 1(graded bySarah North)
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Question 31
Which of the following is not something that a Computer Security policy must address?
1) Secure Communications
2) Privacy
3) Protection
4) Authentication
Save Time
11:09 AM
Score
1
/ 1(graded bySarah North)
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Question 32
Which of the following security attacks involves sending commands to a system that are
incorrectly formatted?
1) Trojan Horse
2) Trap Door
3) Stack and Buffer Overflow
4) Worm
Save Time
11:12 AM
Score
1
/ 1(graded bySarah North)
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Question 33
Transfers between memory and disk are performed a ____.
1) byte at a time
2) file at a time
3) block at a time
4) sector at a time
Save Time
11:13 AM
Score
1
/ 1(graded bySarah North)
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Question 34
A volume control block ____.
1) can contain information needed by the system to boot an operating system from that partition
2) is a directory structure used to organize the files
3) contains many of the file's details, including file permissions, ownership, size, and location of the data
4) contains information such as the number of blocks in a partition, size of the blocks, and free-block and
Save Time
11:13 AM
Score
1
/ 1(graded bySarah North)
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Question 35
The NFS mount protocol ____.
1) does not allow a remote directory to be accessible in a transparent manner
2) exhibits a transitivity property in terms of client access to other file systems
3) establishes the initial logical connection between a server and a client
4) provides a set of RFCs for remote file operations
Save Time
11:16 AM
Score
1
/ 1(graded bySarah North)
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Question 36
Which algorithm is considered reasonable for managing a buffer cache?
1) least-recently-used (LRU)
2) first-in-first-out (FIFO)
3) most-recently-used
4) least-frequently-used (LFU)
Save Time
11:17 AM
Score
1
/ 1(graded bySarah North)
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Question 37
A __________ contains the same pages for memory-mapped IO as well as ordinary IO.
1) double cache
2) unified virtual memory
3) page cahce
4) unified buffer cache
Save Time
11:18 AM
Score
1
/ 1(graded bySarah North)
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Question 38
The most common method used by attackers to breach security is ____.
1) masquerading
2) message modification
3) session hijacking
4) phishing
Save Time
11:20 AM
Score
1
/ 1(graded bySarah North)
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Question 39
A denial of service attack is ____.
1) aimed at gaining information
2) aimed at stealing resources
3) aimed at disrupting legitimate use of a system
4) generally not network based
Save Time
11:20 AM
Score
1
/ 1(graded bySarah North)
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Question 40
The _____ is not an example of a benefit of virtual machines.
1) The ability to run several different operating systems that all share the same hardware
2) The ability to concurrently run several different operating systems
3) Uses less physical memory than an actual operating system
4) Protects the host system from guest operating systems
Save Time
11:21 AM
Score
1
/ 1(graded bySarah North)
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Question 41
Microsoft .NET and the Java virtual machine are examples of __________.
1) Paravirtualization
2) Programming environment virtualization
3) Emulators
4) Type 0 hypervisors
Save Time
12:07 PM
Score
1
/ 1(graded bySarah North)
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Question 42
In systems that support virtual memory, ____.
1) virtual memory is separated from logical memory.
2) virtual memory is separated from physical memory.
3) physical memory is separated from secondary storage.
4) physical memory is separated from logical memory.
Save Time
11:23 AM
Score
1
/ 1(graded bySarah North)
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Question 43
Suppose we have the following page accesses: 1 2 3 4 2 3 4 1 2 1 1 3 1 4 and that there
are three frames within our system. Using the FIFO replacement algorithm, what will be
the final configuration of the three frames following the execution of the given reference
string?
1) 4, 1, 3
2) 3, 1, 4
3) 4, 2, 3
4) 3, 4, 2
Save Time
11:24 AM
Score
1
/ 1(graded bySarah North)
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Question 44
Suppose we have the following page accesses: 1 2 3 4 2 3 4 1 2 1 1 3 1 4 and that there
are three frames within our system. Using the LRU replacement algorithm, what is the
number of page faults for the given reference string?
1) 14
2) 13
3) 8
4) 10
Save Time
11:29 AM
Score
1
/ 1(graded bySarah North)
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Question 45
Optimal page replacement ____.
1) is the page-replacement algorithm most often implemented
2) is used mostly for comparison with other page-replacement schemes
3) can suffer from Belady's anomaly
4) requires that the system keep track of previously used pages
Save Time
11:30 AM
Score
1
/ 1(graded bySarah North)
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Question 46
The _____ occurs when a process spends more time paging than executing.
1) Thrashing
2) Memory-mapping
3) Demand paging
4) Swapping
Save Time
11:30 AM
Score
1
/ 1(graded bySarah North)
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Question 47
Given the reference string of page accesses: 1 2 3 4 2 3 4 1 2 1 1 3 1 4 and a system with
three page frames, what is the final configuration of the three frames after the LRU
algorithm is applied?
1) 1, 3, 4
2) 3, 1, 4
3) 4, 1, 2
4) 1, 2, 3
Save Time
11:31 AM
Score
1
/ 1(graded bySarah North)
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Question 48
One necessary condition for deadlock is ____, which states that at least one resource
must be held in a nonsharable mode.
1) hold and wait
2) mutual exclusion
3) circular wait
4) no preemption
Save Time
11:34 AM
Score
1
/ 1(graded bySarah North)
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Question 49
One necessary condition for deadlock is ______, which states that there is a chain of
waiting processes whereby P0 is waiting for a resource held by P1, P1 is waiting for a
resource held by P2, and Pn is waiting for a resource held by P0.
1) hold and wait
2) mutual exclusion
3) circular wait
4) no preemption
Save Time
11:34 AM
Score
1
/ 1(graded bySarah North)
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Question 50
The _____ is the algorithm implemented on most systems.
FIFO
Least frequently used
Most frequently used
LRU
Save Time
12:07 PM
Score
1
/ 1(graded bySarah North)
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Question 51
Note: Please answer the following questions in your own word in at least 150
words or more. Please note that, this is NOT a group task, therefore, DO NOT
copy or paste from each other or Web.
Explain between internal and external fragmentation.
Note: The Long Answer(LA) questions will be graded by instructor and your
grade will be adjusted after the due date is over and Test is closed. Thank you
Internal fragmentation refers to the wasted disk space that can be left over when a small
file is written to a system that used large clusters. Newer modern disks are improved and
do not often face this issue as often.
External fragmentation refers to when a file is scattered into multiple pieces or clusters
across a disk; this will reduce performance as the OS will have to search for each piece to
access the file properly. This can, and often is, remedied by running a defragmentation
utility, which rearranges the file pieces and places them adjacent to each other, improving
performance.
Save Time
12:07 PM
Score
6
/ 6(graded bySarah North)
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Question 52
Note: Please answer the following questions in your own word in at least 150 words or
more. Please note that, this is NOT a group task, therefore, DO NOT copy or paste from
each other or Web.
1. (a) Explain what thrashing is. (b) Explain what the locality of a process is, and how it is
used to define a working set to help prevent thrashing. (4 points each section)
Thrashing is when a page spends all or more time swapping pages in and out instead of
progressing through its execution, due to too many page faults; essentially, thrashing uses
a lot of resources to do nothing and get nowhere.
The locality of a process refers to the pages in use at the time of process' execution; this
will change over time as pages swap in and out. If the amount of frames allocated for the
locality of a process is too low, then thrashing is likely to occur; conversely, managing
how many frames are allocated to a process' locality (using an algorithm called the
working set algorithm) will assist with preventing thrashing.
Save Time
12:07 PM
Score
8
/ 8(graded bySarah North)
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Question 53
Note: Please answer the following questions in your own word in at least 150 words or
more. Please note that, this is NOT a group task, therefore, DO NOT copy or paste from
each other or Web.
Explain the basic method for implementing paging.
Since physical memory is divided into blocks called frames, when a process is started, it
is loaded into the free frames in small pieces called pages. Pages do not have to be loaded
in order and are usually loaded into memory as needed (called swapping in) to reach
completion, then sent out (swapped out) and replaced with another page (swapped in
again).
Save Time
12:07 PM
Score
6
/ 6(graded bySarah North)
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Question 54
Note: Please answer the following questions in your own word in at least 150 words or
more. Please note that, this is NOT a group task, therefore, DO NOT copy or paste from
each other or Web.
1. (a) Explain the difference between contiguous and non-contiguous memory allocation.
(b) Is internal fragmentation a problem for contiguous memory allocation with fixed
partitions, contiguous memory allocation with dynamic partitions, or both. Explain. (c)
Is external fragmentation a problem for contiguous memory allocation with fixed
partitions, contiguous memory allocation with dynamic partitions, or both. (4 points
each section)
A) Contiguous memory allocation refers to allocating memory into adjacent blocks - that
is, blocks right beside each other; these are called partitions. Non-contiguous memory
allocation refers to the opposite - allocating memory into non-adjacent blocks.
B) Internal fragmentation would most likely not be a problem for contiguous memory
allocation with dynamic partitions because the partitions would adjust to the size of the
file and prevent wasted space. Contiguous memory allocation with fixed partitions are
generally where internal fragmentation occurs most.
C) External fragmentation would probably also not be a problem for contiguous memory
allocation with dynamic partitions, because the partition could adjust to the size of the
files and prevent fragmentation. As with internal fragmentation, contiguous memory
allocation with fixed partitions would probably maintain issues with fragmentation.
Save Time
12:20 PM
Score
12
/ 12(graded bySarah North)
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Question 55
1. (a) Given that <0,40,94,88,34,9,47,6,58,78> are Reader/Writer requests (in cylinders)
in the I/O queue, calculate the total movement in cylinders of the disk arm if the initial
position is 50 and the disk scheduling algorithm is FCFS.
(b) Do the same thing for the same R/W requests if the disk scheduling algorithm
is SSTF and the initial position is still 50.
(c) Finally, for each of the previous cases (FCFS and SSTF), determine the average
seek time if the disk R/W head is moving at a speed of 2ms/cylinder. (4 points each
section)
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Score
0
/ 15(graded bySarah North)
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Question 56
A system has three resource types (A, B, C) and four processes {P1, P2, P3, P4}. The total
units of system resources are: (6, 8, 8) units of A, B and C, respectively. The maximum
demands for each process is P1(4,1,2), P2(3,3,5), P3(3,3,2) and P4(5,1,7). The current
allocation is: P1(0,1,2), P2 (2,1,1), P3 (1,1,2) and P4 (1,1,0).
(a) Create an allocation table for the 3 processes with the following four columns:
PROCESS, ALLOCATION, MAX and NEED. And fill this table with the current
allocation state.
(b) Is this state a safe state? Explain your answer by identifying a successful future
sequence of processes that makes the state safe, or by explaining which processes are
part of the problem that makes the state unsafe?
(a)
PROCESS
ALLOCATION
A B C
MAX
A B C
P1
2 3 1
5 6 2
P2
5 1 4
3 2 4
P3
2 1 2
4 1 2
P4
2 1 1
6 1 8
NEED
A B C
(b)
This state is not a safe state
Save Time
12:23 PM
Score
5
/ 15(graded bySarah North)
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Question 57
Note: Please answer the following questions in your own word in at least 150
words or more. Please note that, this is NOT a group task, therefore, DO NOT
copy or paste from each other or Web.
a) Describe difference between demand paging and pre-paging?
b) Explain what virtual memory is and what is needed to support it?
Note: The Long Answer(LA) questions will be graded by instructor and your
grade will be adjusted after the due date is over and Test is closed. Thank you
A) During demand paging, a page is only loaded into memory when it is referenced by a
process, or demanded. During pre-paging, a page is loaded into memory before it is even
referenced by a process, which leaves it ready when a page finally does reference it.
B) Virtual memory is a technique used by the OS to adjust for a shortage of physical
memory; it does this by temporarily moving process pages from RAM to hard disk
storage, then retrieving them later. In order to support virtual memory, the hardware of
the machine must be able to support paging and/or segmentation, and the OS has to be
able to manage page swapping.
Save Time
12:08 PM
Score
8
/ 8(graded bySarah North)