Os Final Study

Front 1

A race condition ____.
A) results when several threads try to access the same data concurrently
B) results when several threads try to access and modify the same data concurrently
C) will result only if the outcome of execution does not depend on the order in which instructions are executed D) None of the above

Back 1

B) results when several threads try to access and modify the same data concurrently

Front 2

An instruction that executes atomically ____.
A) must consist of only one machine instruction
B) executes as a single, uninterruptible unit
C) cannot be used to solve the critical section problem
D) All of the above

Back 2

B) executes as a single, uninterruptible unit

Front 3

A counting semaphore ____.
A) is essentially an integer variable
B) is accessed through only one standard operation
C) can be modified simultaneously by multiple threads
D) cannot be used to control access to a thread's critical sections

Back 3

A) is essentially an integer variable

Front 4

A mutex lock ____.
A) is exactly like a counting semaphore
B) is essentially a boolean variable
C) is not guaranteed to be atomic
D) can be used to eliminate busy waiting

Back 4

B) is essentially a boolean variable

Front 5

In Peterson's solution, the ____ variable indicates if a process is ready to enter its critical section.
A) turn
B) lock
C) flag[i]
D) turn[i]

Back 5

C) flag[i]

Front 6

The first readers-writers problem ____.
A) requires that, once a writer is ready, that writer performs its write as soon as possible.
B) is not used to test synchronization primitives. C) requires that no reader will be kept waiting unless a writer has already obtained permission to use the shared database.
D) requires that no reader will be kept waiting unless a reader has already obtained permission to use the shared database.

Back 6

C) requires that no reader will be kept waiting unless a writer has already obtained permission to use the shared database.

Front 7

A ___ type presents a set of programmer-defined operations that are provided mutual exclusion within it.
A) transaction
B) signal
C) binary
D) monitor

Back 7

D) monitor

Front 8

____________ occurs when a higher-priority process needs to access a data structure that is currently being accessed by a lower-priority process.
A) Priority inversion
B) Deadlock
C) A race condition
D) A critical section

Back 8

A) Priority inversion

Front 9

What is the correct order of operations for protecting a critical section using mutex locks?
A) release() followed by acquire()
B) acquire() followed by release()
C) wait() followed by signal()
D) signal() followed by wait()

Back 9

B) acquire() followed by release()

Front 10

What is the correct order of operations for protecting a critical section using a binary semaphore?
A) release() followed by acquire()
B) acquire() followed by release()
C) wait() followed by signal()
D) signal() followed by wait()

Back 10

C) wait() followed by signal()

Front 11

_____ is not a technique for handling critical sections in operating systems.
A) Nonpreemptive kernels
B) Preemptive kernels
C) Spinlocks
D) Peterson's solution

Back 11

D) Peterson's solution

Front 12

A solution to the critical section problem does not have to satisfy which of the following requirements? A) mutual exclusion
B) progress
C) atomicity
D) bounded waiting

Back 12

C) atomicity

Front 13

A(n) _______ refers to where a process is accessing/updating shared data.
A) critical section
B) entry section
C) mutex
D) test-and-set

Back 13

A) critical section

Front 14

_____ can be used to prevent busy waiting when implementing a semaphore.
A) Spinlocks
B) Waiting queues
C) Mutex lock
D) Allowing the wait() operation to succeed

Back 14

B) Waiting queues

Front 15

Assume an adaptive mutex is used for accessing shared data on a Solaris system with multiprocessing capabilities. Which of the following statements is not true?
A) A waiting thread may spin while waiting for the lock to become available.
B) A waiting thread may sleep while waiting for the lock to become available.
C) The adaptive mutex is only used to protect short segments of code.
D) Condition variables and semaphores are never used in place of an adaptive mutex.

Back 15

D) Condition variables and semaphores are never used in place of an adaptive mutex.

Front 16

What is the purpose of the mutex semaphore in the implementation of the bounded-buffer problem using semaphores?
A) It indicates the number of empty slots in the buffer.
B) It indicates the number of occupied slots in the buffer.
C) It controls access to the shared buffer.
D) It ensures mutual exclusion.

Back 16

D) It ensures mutual exclusion.

Front 17

How many philosophers may eat simultaneously in the Dining Philosophers problem with 5 philosophers?
A) 1
B) 2
C) 3
D) 5

Back 17

B) 2

Front 18

Which of the following statements is true?
A) A counting semaphore can never be used as a binary semaphore.
B) A binary semaphore can never be used as a counting semaphore.
C) Spinlocks can be used to prevent busy waiting in the implementation of semaphore.
D) Counting semaphores can be used to control access to a resource with a finite number of instances.

Back 18

C) Spinlocks can be used to prevent busy waiting in the implementation of semaphore.

Front 19

_____ is/are not a technique for managing critical sections in operating systems.
A) Peterson's solution
B) Preemptive kernel
C) Nonpreemptive kernel
D) Semaphores

Back 19

A) Peterson's solution

Front 20

When using semaphores, a process invokes the wait() operation before accessing its critical section, followed by the signal() operation upon completion of its critical section. Consider reversing the order of these two operations—first calling signal(), then calling wait(). What
would be a possible outcome of this?
A) Starvation is possible.
B) Several processes could be active in their critical sections at the same time.
C) Mutual exclusion is still assured.
D) Deadlock is possible.

Back 20

B) Several processes could be active in their critical sections at the same time.

Front 21

Which of the following statements is true?
A) Operations on atomic integers do not require locking.
B) Operations on atomic integers do require additional locking.
C) Linux only provides the atomic_inc() and atomic_sub() operations.
D) Operations on atomic integers can be interrupted.

Back 21

A) Operations on atomic integers do not require locking.

Front 22

A(n) ___________ is a sequence of read-write operations that are atomic.
A) atomic integer
B) semaphore
C) memory transaction
D) mutex lock

Back 22

C) memory transaction

Front 23

Another problem related to deadlocks is ____________. A) race conditions
B) critical sections
C) spinlocks
D). indefinite blocking

Back 23

D). indefinite blocking

Front 24

Race conditions are prevented by requiring that critical regions be protected by locks.

Back 24

True

Front 25

The value of a counting semaphore can range only between 0 and 1.

Back 25

False

Front 26

A deadlock-free solution eliminates the possibility of starvation.

Back 26

False

Front 27

The local variables of a monitor can be accessed by only the local procedures.

Back 27

True

Front 28

Every object in Java has associated with it a single lock.

Back 28

True

Front 29

Monitors are a theoretical concept and are not practiced in modern programming languages

Back 29

False

Front 30

A thread will immediately acquire a dispatcher lock that is the signaled state.

Back 30

True

Front 31

Mutex locks and counting semaphores are essentially the same thing.

Back 31

False

Front 32

Mutex locks and binary semaphores are essentially the same thing.

Back 32

True

Front 33

A nonpreemptive kernel is safe from race conditions on kernel data structures.

Back 33

True

Front 34

Linux mostly uses atomic integers to manage race conditions within the kernel.

Back 34

False

Front 35

A deadlocked state occurs whenever ____.
A) a process is waiting for I/O to a device that does not exist
B) the system has no available free resources
C) every process in a set is waiting for an event that can only be caused by another process in the set
D) a process is unable to release its request for a resource after use

Back 35

C) every process in a set is waiting for an event that can only be caused by another process in the set

Front 36

One necessary condition for deadlock is ____, which states that at least one resource must be held in a nonsharable mode.
A) hold and wait
B) mutual exclusion
C) circular wait
D) no preemption

Back 36

B) mutual exclusion

Front 37

One necessary condition for deadlock is ______, which states that a process must be holding one resource and waiting to acquire additional resources.
A) hold and wait
B) mutual exclusion
C) circular wait
D) no preemption

Back 37

A) hold and wait

Front 38

One necessary condition for deadlock is ______, which states that a resource can be released only voluntarily by the process holding the resource.
A) hold and wait
B) mutual exclusion
C) circular wait
D) no preemption

Back 38

D) no preemption

Front 39

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.
A) hold and wait
B) mutual exclusion
C) circular wait
D) no preemption

Back 39

C) circular wait

Front 40

The witness software product is a ____.
A) lock-order verifier that uses mutual-exclusion locks to protect critical sections
B) modeler to develop resource allocation graphs C) driver that can be used to prevent mutual exclusion for nonsharable resources
D) implementation of the banker's algorithm available for most operating systems

Back 40

A) lock-order verifier that uses mutual-exclusion locks to protect critical sections

Front 41

In a system resource-allocation graph, ____.
A) a directed edge from a process to a resource is called an assignment edge
B) a directed edge from a resource to a process is called a request edge
C) a directed edge from a process to a resource is called a request edge
D) None of the above

Back 41

C) a directed edge from a process to a resource is called a request edge

Front 42

A cycle in a resource-allocation graph is ____.
A) a necessary and sufficient condition for deadlock in the case that each resource has more than one instance
B) a necessary and sufficient condition for a deadlock in the case that each resource has exactly one instance
C) a sufficient condition for a deadlock in the case that each resource has more than once instance D) is neither necessary nor sufficient for indicating deadlock in the case that each resource has exactly one instance

Back 42

B) a necessary and sufficient condition for a deadlock in the case that each resource has exactly one instance

Front 43

To handle deadlocks, operating systems most often _____.
A) pretend that deadlocks never occur
B) use protocols to prevent or avoid deadlocks
C) detect and recover from deadlocks
D) None of the above

Back 43

A) pretend that deadlocks never occur

Front 44

Which of the following statements is true?
A) A safe state is a deadlocked state.
B) A safe state may lead to a deadlocked state.
C) An unsafe state is necessarily, and by definition, always a deadlocked state.
D) An unsafe state may lead to a deadlocked state.

Back 44

D) An unsafe state may lead to a deadlocked state.

Front 45

Suppose that there are ten resources available to three processes. At time 0, the following data is collected. The table indicates the process, the maximum number of resources needed by the process, and the number of resources currently owned by each process. Which of the following correctly characterizes this state?
Process Maximum Needs Currently Owned
P0 10 4
P1 3 1
P2 6 4
A) It is safe.
B) It is not safe.
C) The state cannot be determined.
D) It is an impossible state.

Back 45

B) It is not safe.

Front 46

Suppose that there are 12 resources available to three processes. At time 0, the following data is collected. The table indicates the process, the maximum number of resources needed by the process, and the number of resources currently owned by each process. Which of the following correctly characterizes this state?
Process Maximum Needs Currently Owned
P0 10 4
P1 3 2
P2 7 4
A) It is safe.
B) It is not safe.
C) The state cannot be determined.
D) It is an impossible state.

Back 46

A) It is safe.

Front 47

Which of the following data structures in the banker's algorithm is a vector of length m, where m is the number of resource types?
A) Need
B) Allocation
C) Max
D) Available

Back 47

D) Available

Front 48

Assume there are three resources, R1, R2, and R3, that are each assigned unique integer values 15, 10, and 25, respectively. What is a resource ordering which prevents a circular wait?
A) R1, R2, R3
B) R3, R2, R1
C) R3, R1, R2
D) R2, R1, R3

Back 48

D) R2, R1, R3

Front 49

A _____ could be preempted from a process.
A) mutex lock
B) CPU
C) semaphore
D) file lock

Back 49

B) CPU

Front 50

The circular-wait condition for a deadlock implies the hold-and-wait condition.

Back 50

True

Front 51

If a resource-allocation graph has a cycle, the system must be in a deadlocked state.

Back 51

False

Front 52

Protocols to prevent hold-and-wait conditions typically also prevent starvation.

Back 52

False

Front 53

The wait-for graph scheme is not applicable to a resource allocation system with multiple instances of each resource type.

Back 53

True

Front 54

Ordering resources and requiring the resources to be acquired in order prevents the circular wait from occurring and therefore prevents deadlock from occurring.

Back 54

False

Front 55

The banker's algorithm is useful in a system with multiple instances of each resource type.

Back 55

True

Front 56

A system in an unsafe state will ultimately deadlock.

Back 56

False

Front 57

Deadlock prevention and deadlock avoidance are essentially the same approaches for handling deadlock.

Back 57

False

Front 58

Absolute code can be generated for ____.
A) compile-time binding
B) load-time binding
C) execution-time binding
D) interrupt binding

Back 58

A) compile-time binding

Front 59

_____ is the method of binding instructions and data to memory performed by most general- purpose operating systems.
A) Interrupt binding
B) Compile time binding
C) Execution time binding
D) Load-time binding

Back 59

C) Execution time binding

Front 60

An address generated by a CPU is referred to as a ____.
A) physical address
B) logical address
C) post relocation register address
D) Memory-Management Unit (MMU) generated address

Back 60

B) logical address

Front 61

Suppose a program is operating with execution-time binding and the physical address generated is 300. The relocation register is set to 100. What is the corresponding logical address?
A) 199
B) 201
C) 200
D) 300

Back 61

C) 200

Front 62

The mapping of a logical address to a physical address is done in hardware by the ________.
A) memory-management-unit (MMU)
B) memory address register
C) relocation register
D) dynamic loading register

Back 62

A) memory-management-unit (MMU)

Front 63

In a dynamically linked library, ____.
A) loading is postponed until execution time
B) system language libraries are treated like any other object module
C) more disk space is used than in a statically linked library
D) a stub is included in the image for each library-routine reference

Back 63

D) a stub is included in the image for each library-routine reference

Front 64

The _____ binding scheme facilitates swapping.
A) interrupt time
B) load time
C) assembly time
D) execution time

Back 64

D) execution time

Front 65

The roll out, roll in variant of swapping is used ____.
A) when a backing store is not necessary
B) for the round-robin scheduling algorithm
C) for priority-based scheduling algorithms
D) when the load on the system has temporarily been reduced

Back 65

C) for priority-based scheduling algorithms

Front 66

_____ is the dynamic storage-allocation algorithm which results in the smallest leftover hole in memory.
A) First fit
B) Best fit
C) Worst fit
D) None of the above

Back 66

B) Best fit

Front 67

_____ is the dynamic storage-allocation algorithm which results in the largest leftover hole in memory. A) First fit
B) Best fit
C) Worst fit
D) None of the above

Back 67

C) Worst fit

Front 68

Which of the following is true of compaction?
A) It can be done at assembly, load, or execution time.
B) It is used to solve the problem of internal fragmentation.
C) It cannot shuffle memory contents.
D) It is possible only if relocation is dynamic and done at execution time.

Back 68

D) It is possible only if relocation is dynamic and done at execution time.

Front 69

A(n) ____ page table has one page entry for each real page (or frame) of memory.
A) inverted
B) clustered
C) forward-mapped
D) virtual

Back 69

A) inverted

Front 70

Consider a logical address with a page size of 8 KB. How many bits must be used to represent the page offset in the logical address?
A) 10
B) 8
C) 13
D) 12

Back 70

C) 13

Front 71

Consider a logical address with 18 bits used to represent an entry in a conventional page table. How many entries are in the conventional page table?
A) 262144
B) 1024
C) 1048576
D) 18

Back 71

A) 262144

Front 72

Assume a system has a TLB hit ratio of 90%. It requires 15 nanoseconds to access the TLB, and 85 nanoseconds to access main memory. What is the effective memory access time in nanoseconds for this system?
A) 108.5
B) 100
C) 22
D) 176.5

Back 72

A) 108.5

Front 73

Given the logical address 0xAEF9 (in hexadecimal) with a page size of 256 bytes, what is the page number?
A) 0xAE
B) 0xF9
C) 0xA
D) 0x00F9

Back 73

A) 0xAE

Front 74

Given the logical address 0xAEF9 (in hexadecimal) with a page size of 256 bytes, what is the page offset?
A) 0xAE
B) 0xF9
C) 0xA
D) 0xF900

Back 74

B) 0xF9

Front 75

Consider a 32-bit address for a two-level paging system with an 8 KB page size. The outer page table has 1024 entries. How many bits are used to represent the second-level page table?
A) 10
B) 8
C) 12
D) 9

Back 75

D) 9

Front 76

With segmentation, a logical address consists of _____.
A) segment number and offset
B) segment name and offset
C) segment number and page number
D) segment table and segment number

Back 76

A) segment number and offset

Front 77

Which of the following data structures is appropriate for placing into its own segment?
A) heap
B) kernel code and data
C) user code and data
D) all of the above

Back 77

D) all of the above

Front 78

Assume the value of the base and limit registers are 1200 and 350 respectively. Which of the following addresses is legal?
A) 355
B) 1200
C) 1551
D) all of the above

Back 78

B) 1200

Front 79

A(n) ______ matches the process with each entry in the TLB.
A) address-space identifier
B) process id
C) stack
D) page number

Back 79

A) address-space identifier

Front 80

Which of the following statements are true with respect to hashed page tables?
A) They only work for sparse address spaces.
B) The virtual address is used to hash into the hash table.
C) A common approach for handling address spaces larger than 32 bits.
D) Hash table collisions do not occur because of the importance of paging.

Back 80

C) A common approach for handling address spaces larger than 32 bits.

Front 81

Which of the following statements regarding the ARM architecture are false?
A) There are essentially four different page ranging from 4-KB to 16-MB in size.
B) There are two different levels of TLB.
C) One or two level paging may be used.
D) The micro TLB must be flushed at each context switch.

Back 81

D) The micro TLB must be flushed at each context switch.

Front 82

Which of the following is not a reason explaining why mobile devices generally do not support swapping?
A) Limited space constraints of flash memory.
B) Small size of mobile applications do not require use of swap space.
C) Limited number of writes of flash memory.
D) Poor throughput between main memory and flash memory.

Back 82

B) Small size of mobile applications do not require use of swap space.

Front 83

A relocation register is used to check for invalid memory addresses generated by a CPU.

Back 83

False

Front 84

Reentrant code cannot be shared.

Back 84

False

Front 85

There is a 1:1 correspondence between the number of entries in the TLB and the number of entries in the page table.

Back 85

False

Front 86

Hierarchical page tables are appropriate for 64-bit architectures.

Back 86

False

Front 87

The ARM architecture uses both single-level and two-level paging.

Back 87

True

Front 88

Fragmentation does not occur in a paging system.

Back 88

False

Front 89

Hashed page tables are particularly useful for processes with sparse address spaces.

Back 89

True

Front 90

Inverted page tables require each process to have its own page table.

Back 90

False

Front 91

Without a mechanism such as an address-space identifier, the TLB must be flushed during a context switch.

Back 91

True

Front 92

A 32-bit logical address with 8 KB page size will have 1,000,000 entries in a conventional page table.

Back 92

False

Front 93

Hashed page tables are commonly used when handling addresses larger than 32 bits.

Back 93

True

Front 94

The x86-64 bit architecture only uses 48 of the 64 possible bits for representing virtual address space.

Back 94

True

Front 95

Mobile operating systems typically support swapping.

Back 95

False

Front 96

Which of the following is a benefit of allowing a program that is only partially in memory to execute?
A) Programs can be written to use more memory than is available in physical memory.
B) CPU utilization and throughput is increased.
C) Less I/O is needed to load or swap each user program into memory.
D) All of the above

Back 96

D) All of the above

Front 97

In systems that support virtual memory, ____.
A) virtual memory is separated from logical memory.
B) virtual memory is separated from physical memory.
C) physical memory is separated from secondary storage.
D) physical memory is separated from logical memory.

Back 97

D) physical memory is separated from logical memory.

Front 98

The vfork() system call in UNIX____.
A) allows the child process to use the address space of the parent
B) usescopy-on-writewiththefork()call
C) is not intended to be used when the child process calls exec() immediately after creation
D) duplicates all pages that are modified by the child process

Back 98

A) allows the child process to use the address space of the parent

Front 99

Suppose we have the following page accesses:12342341211314 and that there are three frames within our system. Using the FIFO replacement algorithm, what is the number of page faults for the given reference string?
A) 14
B) 8
C) 13
D) 10

Back 99

B) 8

Front 100

Supposewehavethefollowingpageaccesses:12342341211314andthatthereare 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? A) 4,1,3
B) 3, 1, 4
C) 4, 2, 3
D) 3,4,2

Back 100

D) 3,4,2

Front 101

Supposewehavethefollowingpageaccesses:12342341211314andthatthereare three frames within our system. Using the LRU replacement algorithm, what is the number of page faults for the given reference string?
A) 14
B) 13
C) 8
D) 10

Back 101

C) 8

Front 102

Given the reference string of page accesses:12342341211314 and a system with three page frames, what is the final configuration of the three frames after the LRU algorithm is applied?
A) 1,3,4
B) 3, 1, 4
C) 4, 1, 2
D) 1,2,3

Back 102

B) 3, 1, 4

Front 103

Belady's anomaly states that ____.
A) giving more memory to a process will improve its performance
B) as the number of allocated frames increases, the page-fault rate may decrease for all page replacement algorithms
C) for some page replacement algorithms, the page-fault rate may decrease as the number of allocated frames increases
D) for some page replacement algorithms, the page-fault rate may increase as the number of allocated frames increases

Back 103

D) for some page replacement algorithms, the page-fault rate may increase as the number of allocated frames increases

Front 104

Optimal page replacement ____.
A) is the page-replacement algorithm most often implemented
B) is used mostly for comparison with other page-replacement schemes
C) can suffer from Belady's anomaly
D) requires that the system keep track of previously used pages

Back 104

B) is used mostly for comparison with other page-replacement schemes

Front 105

In the enhanced second chance algorithm, which of the following ordered pairs represents a page that would be the best choice for replacement?
A) (0,0)
B) (0,1)
C) (1,0)
D) (1,1)

Back 105

A) (0,0)

Front 106

The _____ allocation algorithm allocates available memory to each process according to its size.
A) equal
B) global
C) proportional
D) slab

Back 106

C) proportional

Front 107

The ____ is the number of entries in the TLB multiplied by the page size.
A) TLB cache
B) page resolution
C) TLB reach
D) hit ratio

Back 107

C) TLB reach

Front 108

________ allows the parent and child processes to initially share the same pages, but when either process modifies a page, a copy of the shared page is created.
A) copy-on-write
B) zero-fill-on-demand
C) memory-mapped
D) virtual memory fork

Back 108

A) copy-on-write

Front 109

_____ is the algorithm implemented on most systems. A) FIFO
B) Least frequently used
C) Most frequently used
D) LRU

Back 109

D) LRU

Front 110

____ occurs when a process spends more time paging than executing.
A) Thrashing
B) Memory-mapping
C) Demand paging
D) Swapping

Back 110

A) Thrashing

Front 111

Windows uses a local page replacement policy _____.
A) when a process exceeds its working set minimum
B) when a process exceeds its working set maximum
C) when the system undergoes automatic working set trimming
D) under all circumstances

Back 111

B) when a process exceeds its working set maximum

Front 112

Which of the following statements is false with regard to Solaris memory management?
A) The speed at which pages are examined (the scanrate) is constant.
B) The pageout process only runs if the number of free pages is less than lotsfree.
C) An LRU approximation algorithm is employed.
D) Pages selected for replacement may be reclaimed before being placed on the free list.

Back 112

A) The speed at which pages are examined (the scanrate) is constant.

Front 113

What size segment will be allocated for a 39 KB request on a system using the Buddy system for kernel memory allocation?
A) 39 KB
B) 42 KB
C) 64 KB
D) None of the above

Back 113

C) 64 KB

Front 114

Which of the following statements is false with regard to allocating kernel memory?
A) Slab allocation does not suffer from fragmentation.
B) Adjacent segments can be combined into one larger segment with the buddy system.
C) Because the kernel requests memory of varying sizes, some of which may be quite small, the system does not have to be concerned about wasting memory.
D) The slab allocator allows memory requests to be satisfied very quickly.

Back 114

C) Because the kernel requests memory of varying sizes, some of which may be quite small, the system does not have to be concerned about wasting memory.

Front 115

The _____ is an approximation of a program's locality. A) locality model
B) working set
C) page fault frequency
D) page replacement algorithm

Back 115

B) working set

Front 116

______ allows a portion of a virtual address space to be logically associated with a file.
A) Memory-mapping
B) Shared memory
C) Slab allocation
D) Locality of reference

Back 116

A) Memory-mapping

Front 117

Systems in which memory access times vary significantly are known as __________.
A) memory-mapped I/O
B) demand-paged memory
C) non-uniform memory access
D) copy-on-write memory

Back 117

C) non-uniform memory access

Front 118

Which of the following is considered a benefit when using the slab allocator?
A) Memory is allocated using a simple power-of-2 allocator.
B) It allows kernel code and data to be efficiently paged.
C) It allows larger segments to be combined using coalescing.
D) There is no memory fragmentation.

Back 118

D) There is no memory fragmentation.

Front 119

In general, virtual memory decreases the degree of multiprogramming in a system.

Back 119

False

Front 120

Stack algorithms can never exhibit Belady's anomaly.

Back 120

True

Front 121

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

Back 121

False

Front 122

The buddy system for allocating kernel memory is very likely to cause fragmentation within the allocated segments.

Back 122

True

Front 123

On a system with demand-paging, a process will experience a high page fault rate when the process begins execution.

Back 123

True

Front 124

On systems that provide it, vfork() should always be used instead of fork().

Back 124

False

Front 125

Only a fraction of a process's working set needs to be stored in the TLB.

Back 125

False

Front 126

Solaris uses both a local and global page replacement policy.

Back 126

False

Front 127

Windows uses both a local and global page replacement policy.

Back 127

False

Front 128

A page fault must be preceded by a TLB miss.

Back 128

True

Front 129

Non-uniform memory access has little effect on the performance of a virtual memory system.

Back 129

False

Front 130

In Linux, a slab may only be either full or empty.

Back 130

False

Front 131

Transfers between memory and disk are performed a ____.
A) byte at a time
B) file at a time
C) block at a time
D) sector at a time

Back 131

C) block at a time

Front 132

Order the following file system layers in order of lowest level to highest level.
[1] I/O control
[2]logical file system
[3] basic file system
[4]file-organization module
[5]devices

A) 1,3,5,4,2
B) 5, 1, 3, 2, 4
C) 1, 5, 3, 4, 2
D)5,1,3,4,2

Back 132

D)5,1,3,4,2

Front 133

A volume control block ____.
A) can contain information needed by the system to boot an operating system from that partition
B) is a directory structure used to organize the files
C) contains many of the file's details, including file permissions, ownership, size, and location of the data blocks
D) contains information such as the number of blocks in a partition, size of the blocks, and free- block and FCB count and pointers

Back 133

D) contains information such as the number of blocks in a partition, size of the blocks, and free- block and FCB count and pointers

Front 134

Which of the following is the simplest method for implementing a directory?
A) tree data structure
B) linear list
C) hash table
D) nonlinear list

Back 134

B) linear list

Front 135

In the Linux VFS architecture, a(n) ____ object represents an individual file.
A) inode
B) file
C) superblock
D) dentry

Back 135

A) inode

Front 136

Which of the following allocation methods ensures that only one access is needed to get a disk block using direct access?
A) linked allocation
B) indexed allocation
C) hashed allocation
D) contiguous allocation

Back 136

D) contiguous allocation

Front 137

The free-space list can be implemented using a bit vector approach. Which of the following is a drawback of this technique?
A) To traverse the list, each block must be read on the disk.
B) It is not feasible to keep the entire list in main memory for large disks.
C) The technique is more complicated than most other techniques.
D) This technique is not feasible for small disks.

Back 137

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

Front 138

Page caching ____.
A) uses virtual memory techniques to cache file data as system-oriented blocks as opposed to pages
B) uses virtual memory techniques to cache file data as pages as opposed to system-oriented blocks.
C) is used in Windows NT but not in Windows 2000.
D) cannot be used to cache both process pages and file data.

Back 138

B) uses virtual memory techniques to cache file data as pages as opposed to system-oriented blocks.

Front 139

NFS views a set of interconnected workstations as a set of ____.
A) independent machines with independent file systems
B) dependent machines with independent file systems
C) dependent machines with dependent file systems
D) independent machines with dependent file systems

Back 139

A) independent machines with independent file systems

Front 140

The NFS mount protocol ____.
A) does not allow a remote directory to be accessible in a transparent manner
B) exhibits a transitivity property in terms of client access to other file systems
C) establishes the initial logical connection between a server and a client
D) provides a set of RFCs for remote file operations

Back 140

C) establishes the initial logical connection between a server and a client

Front 141

A disk with free blocks 0,1,5,9,15 would be represented with what bit map?
A) 0011101110111110
B) 1100010001000001
C) 0100010001000001
D) 1100010001000000

Back 141

B) 1100010001000001

Front 142

A _____ is a view of a file system before the last update took place.
A) transaction
B) backup
C) consistency checker
D) snapshot

Back 142

D) snapshot

Front 143

______ includes all of the file system structure, minus the actual contents of files.
A) Metadata
B) Logical file system
C) Basic file system
D) File-organization module

Back 143

A) Metadata

Front 144

The file-allocation table (FAT) used in MS-DOS is an example of _____.
A) contiguous allocation
B) indexed allocation
C) linked allocation
D) multilevel index

Back 144

C) linked allocation

Front 145

How many disk accesses are necessary for direct access to byte 20680 using linked allocation and assuming each disk block is 4 KB in size?
A) 1
B) 6
C) 7
D) 5

Back 145

B) 6

Front 146

A contiguous chunk of disk blocks is known as a(n) _____.
A) extent
B) disk block group
C) inode
D) file-allocation table (FAT)

Back 146

A) extent

Front 147

On UNIX systems, the data structure for maintaining information about a file is a(n) _____.
A) superblock
B) inode
C) file-control block (FCB)
D) master file table

Back 147

B) inode

Front 148

Which algorithm is considered reasonable for managing a buffer cache?
A) least-recently-used (LRU)
B) first-in-first-out (FIFO)
C) most-recently-used
D) least-frequently-used (LFU)

Back 148

A) least-recently-used (LRU)

Front 149

Which of the following statements regarding the WAFL file system is incorrect?
A) Clones are similar to snapshots.
B) WAFL is used exclusively on networked file servers.
C) Part of caching uses non-volatile RAM (NVRAM.)
D) It provides little replication.

Back 149

D) It provides little replication.

Front 150

Consider a system crash on a log-structured file system. Which one of the following events must occur?
A) Only aborted transactions must be completed. B) All transactions in the log must be completed. C) All transactions in the log must be marked as invalid.
D) File consistency checking must be performed.

Back 150

B) All transactions in the log must be completed.

Front 151

A __________ contains the same pages for memory-mapped IO as well as ordinary IO.
A) double cache
B) unified virtual memory
C) page cahce
D) unified buffer cache

Back 151

D) unified buffer cache

Front 152

Metadata includes all of the file-system structure, including the actual data (or contents of the file).

Back 152

False

Front 153

In NTFS, the volume control block (per volume) and the directory structure (per file system) is stored in the master file table.

Back 153

True

Front 154

Indexed allocation may require substantial overhead for its index block.

Back 154

True

Front 155

The NFS protocol provides concurrency-control mechanisms.

Back 155

False

Front 156

On log-structured file systems, all metadata and file data updates are written sequentially to a log.

Back 156

False

Front 157

VFS allows dissimilar file systems to be accessed similarly.

Back 157

True

Front 158

Linked allocation suffers from external fragmentation.

Back 158

False

Front 159

The WAFL file system can be used in conjunction with NFS.

Back 159

True

Front 160

On log-structured file systems, a transaction is considered only when it is written to disk.

Back 160

False

Front 161

A unified buffer cache uses the same cache for ordinary disk I/O as well as memory-mapped I/ O.

Back 161

True

Front 162

A consistency checker only checks for inconsistencies, it cannot fix any that it may find.

Back 162

False

Front 163

Asynchronous writes to a file system are generally more efficient than synchronous writes.

Back 163

True