OS Final CH 6-14
For deadlock to occur, there must not only be a fatal region, but also a sequence of resource requests that has led into the fatal region
True
Hardware atomic instruction TestAndSet can be used to implement mutex lock.
True
Hardware atomic instructions TestAndSet can be used to implement mutex locks
True
Hashed page tables are commonly used when handling addresses larger than 32 bits
True
Hashed page tables are commonly used when handling addresses larger than 32 bits.
True
Hashed page tables are particularly useful for processes with sparse address spaces
True
Hashed page tables are particularly useful for processes with sparse address spaces.
True
IA-32 page tables can be swapped to disk.
True
If access to a resource requires mutual exclusion then mutual exclusion must be supported by the OS
True
In Solaris, swap space is only used as a backing store for pages of anonymous memory
True
In general, LOOK disk head scheduling will involve less movement of the disk heads than SCAN disk head scheduling.
True
In general- Windows system calls have longer- more descriptive names and UNIX system calls use shorter- less descriptive names.
True
In hard real-time systems- interrupt latency must be bounded.
True
In most RAID implementations, a hot spare disk is not used for data, but is configured for replacement should any other disk fail.
True
In preemptive scheduling- the sections of code affected by interrupts must be guarded from simultaneous use.
True
In the Linux CFS scheduler- the task with smallest value of vruntime is considered to have the highest priority.
True
In the execution-time address binding scheme, the user program never sees the real physical addresses
True
In the reader-writers problem multiple readers are allowed to read the shared data at the same time
True
In the readers-writers problem, multiple readers are allowed to read the shared data at the same time
True
Increasing page size would improve TLB reach but also increase fragmentation
True
Instructions from different processes can be interleaved when interrupts are allowed.
True
Interrupts may be triggered by either hardware of software
True
It is more expensive to evict a dirty page than a clean page
True
It is more expensive to evict a dirty page than a clean page.
True
It is possible to create a thread library without any kernel-level support.
True
It is possible to have concurrency without parallelism.
True
KDE and GNOME desktops are available under open-source licenses
True
LRU page replacement algorithm does not exhibit Belady's anomaly
True
LRU page replacement algorithm doesn't exhibit Belady's anomaly.
True
Local Procedure Calls in Windows XP are similar to Remote Procedure Calls
True
Lock ordering cannot guarantee protection from deadlock.
True
Logical-file system is responsible for both managing metadata information and protection:
True
Mac OS X is a hybrid system consisting of both the Mach microkernel and BSD UNIX
True
Many operating system merge I/O devices and files into a combined file because of the similarity of system calls for each.
True
Memory compression is commonly used in mobile systems instead of swapping.
True
Most contemporary computers store page tables in main memory
True
Mutex locks and binary semaphores are essentially the same thing
True
Mutex locks and binary semaphores are essentially the same thing.
True
Named pipes continue to exist in the system after the creating process has terminated
True
On a system with demand-paging, a process will experience a high page fault rate when the process begins execution.
True
On a system with demand-paging- a process will experience a high page fault rate when the process begins execution
True
OpenMP only works for C- C++- and Fortran programs.
True
Ordinary pipes in UNIX require a parent-child relationship between the communicating processes.
True
Ordinary pipes in Windows require a parent-child relationship between the communicating processes.
True
Page table itself is also paged in a hierarchical paging scheme
True
Page table itself is also pages in a hierarchical paging scheme
True
Paging memory management scheme allows the sharing of common code among processes
True
Paging memory management scheme allows the sharing of common code among processes.
True
Processors for most mobile devices run at a slower speed than a processor in a desktop PC.
True
RAID level 0 provides no redundancy.
True
Race conditions are prevented by requiring that critical regions be protected by locks.
True
Race conditions are prevented by requiring that criticalregions be protected by locks
True
Round-robin (RR) scheduling degenerates to first-come-first-served (FCFS) scheduling if the time quantum is too long.
True
SMP systems that use multicore processors typically run faster than SMP systems that place each processor on separate cores.
True
STREAMS I/O is asynchronous except when the user process communicates with the stream head.
True
Simple operation of listing the contents of a specific directory, when unprotected, may be a threat to the system security:
True
Solid state disks are generally faster than magnetic disks.
True
Spinlocks are often used in a multiprocessor systems but not appropriate for single-processor systems
True
Spinlocks are often used in multiprocessor systems but not appropriate for single-processes systems.
True
Stack algorithms can never exhibit Belady's anomaly
True
Suppose that a system is in an unsafe state. It is possible for the processes to complete their execution without entering a deadlock state
True
Tertiary storage is usually implemented as a jukebox of tapes or removable disks.
True
The ARM architecture uses both single-level and two-level pagin
True
The ARM architecture uses up to four-level paging.
True
The Completely Fair Scheduler (CFS) is the default scheduler for Linux systems
True
The Intel IA-32 architecture uses both single level and two level paging
True
The Intel IA-32 architecture uses both single-level and two-level paging.
True
The Linux operating system does not rely on segmentation and uses it minimally.
True
The Mach operating system treats system calls with message passing
True
The OS may preempt the second process and require it to release its resources if a process requests a resource that is currently held by another process
True
The banker's algorithm is useful for deadlock avoidance in a system with multiple instances of each resource type
True
The banker's algorithm is useful in a system with multiple instances of each resource type.
True
The buddy system for allocating kernel memory is very likely to cause fragmentation within the allocated segments.
True
The circular-wait condition for a deadlock implies the hold-and-wait condition.
True
The decision of when to invoke a detection algorithm depends on the likely frequency of deadlocks and the number of threads likely to be affected by a deadlock when it happens.
True
The dining philosophers problem can be representative of problems dealing with the coordination of shared resources which may occur when an application includes concurrent threads of execution
True
The iOS mobile operating system only supports a limited form of multitasking.
True
The local variables of a monitor can be accessed by only the local procedures
True
The local variables of a monitor can be accessed by only the local procedures.
True
The most common approach to file protection is to make access dependent upon the identity of the user.
True
The most complex scheduling algorithm is the multilevel feedback-queue algorithm.
True
The trend in developing parallel applications is to use implicit threading.
True
The wait() operation of a conditional variable always suspends the calling thread and releases the mutex lock
True
The wait() operation of a conditional variable suspends the calling thread and releases the mutex lock
True
The wait-for graph scheme is not applicable to a resource allocation system with multiple instances of each resource type.
True
The x86-64 bit architecture only uses 48 of the 64 possible bits for representing virtual address space.
True
There is no universally accepted definition of an operating system.
True
Typically, a mount point is an empty directory.
True
Using a section object to pass messages over a connection port avoids data copying.
True
Virtually all contemporary operating systems support kernel threads.
True
Virtually all modern operating systems provide support for SMP
True
When a new file is added to the directory, it is being appended at the end of it:
True
Windows 7 User-mode scheduling (UMS) allows applications to create and manage thread independently of the kernel
True
Windows systems employ mandatory locking.
True
Without a mechanism such as an address-space identifier, the TLB must be flushed during a context switch.
True
Without a mechanism such as an address-space identifier- the TLB must be flushed during a context switch.
True
nonpreemptive kernel is safe from race conditions on kernel data structures.
True
Which of the following statements is false?
Typically, entire processes are swapped into memory.
A __________ contains the same pages for memory-mapped IO as well as ordinary IO.
Unified buffer cache
Page caching ____.
Uses virtual memory techniques to cache file data as pages as opposed to system-oriented blocks.
_____ can be used to prevent busy waiting when implementing a semaphore.
Waiting queues
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?
108.5
Assume the value of the base and limit registers are 1200 and 350 respectively. Which of the following addresses is legal?
1200
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?
13
How many philosophers may eat simultaneously in the Dining Philosophers problem with 5 philosophers?
2
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?
200
RAID level ____ is the most common parity RAID system.
5
Which RAID level is best for storing large volumes of data?
5
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
5, 1, 3, 4, 2 devices, I/0 control, basic file system. file-organization module, logical file system
Which of the following statements are true with respect to hashed page tables?
A common approach for handling address spaces larger than 32 bits.
_________ can be defined as the permanent blocking of a set of processes that either compete for system resources or communicate with each other.
Deadlock
A set of processes is _________ when each process in the set is blocked awaiting an event that can only be triggered by another blocked process in the set.
Deadlocked
Three general approaches exist for dealing with deadlock: prevent, avoid, and __________ .
Detect
The NFS mount protocol ____.
Establishes the initial logical connection between a server and a client
A(n) ____ file is a series of code sections that the loader can bring into memory and execute.
Executable
____ is the method of binding instructions and data to memory performed by most general-purpose operating systems.
Execution time binding
_____ is the method of binding instructions and data to memory performed by most general-purpose operating systems.
Execution time binding
A contiguous chunk of disk blocks is known as a(n) _____.
Extent
Which of the following disk head scheduling algorithms does not take into account the current position of the disk head?
FCFS
iOS is open source, Android is closed source.
Fal
A 32-bit logical address with 8 KB page size will have 1,000,000 entries in a conventional page table.
False
A 32-bit logical address with 8 KB page size will have 1-000-000 entries in a conventional page table
False
A Solaris interactive thread with priority 15 has a higher relative priority than an interactive thread with priority 20
False
A deadlock-free solution eliminates the possibility of starvation.
False
A deadlock-free solution of the dining-philosophers problem eliminates the possibility of starvation.
False
A dual-core system requires each core has its own cache memory.
False
A free space list may be implemented as various structures, not only as a list:
False
A new browser process is create by the Chrome browser for every new website that is visited
False
A relative path name begins at the root.
False
A relocation register is used to check for invalid memory addresses generated by a CPU.
False
A system call is triggered by hardware
False
A system in an unsafe state will ultimately deadlock.
False
A thread is composed of a thread ID, program counter, register set, and heap.
False
All access to POSIX shared memory requires a system call
False
All computer systems have some sort of user interaction.
False
An indirect method of deadlock prevention is to prevent the occurrence of a circular wait
False
An initial bootstrap program is in the form of random-access memory (RAM).
False
An unsafe state is one in which there is at least one sequence of resource allocations to process that does not result in a deadlock
False
As a general rule, UNIX systems employ mandatory locks.
False
Data striping provides reliability for RAID systems.
False
Deadlock avoidance is more restrictive than deadlock prevention
False
Deadlock detection and recovery is the method for dealing with deadlocks used in most OS, including linux and windows
False
Deadlock detection and recovery is the method for dealing with deadlocks used in most operating systems, including Linux and Windows.
False
Deadlock prevention and deadlock avoidance are essentially the same approaches for handling deadlock
False
Deadlock prevention and deadlock avoidance are essentially the same approaches for handling deadlock.
False
Deadlock prevention by denying the mutual-exclusion condition is the simplest way to prevent deadlocks.
False
Disk controllers do not usually have a built-in cache.
False
Dynamic linking would result in a larger size executables than static linking.
False
Dynamic linking would result in larger size executables than static linking
False
For logical memory of the same size, a page table for larger page size would have more entries than that of smaller page size.
False
For logical memory of the same size, page table of larger size would have more entries than that of a smaller size
False
Fragmentation does not occur in a paging system.
False
Grand Central Dispatch requires multiple threads
False
Hierarchical page tables are appropriate for 64-bit architectures.
False
I/O subsystem is integrated into process manager, memory manager and file system.
False
If a resource-allocation graph has a cycle, the system must be in a deadlocked state.
False
If the page fault rate is too high, it means that the process may have to many frames
False
If the page-fault rate is too high, it means that the process may have too many frames.
False
If the page-fault rate is too high- the process may have too many frames
False
In Java- data shared between threads is simply declared globally.
False
In Linux, a slab may only be either full or empty.
False
In Pthread real-time scheduling- the SCHED_FIFO class provides time slicing among threads of equal priority.
False
In RR scheduling- the time quantum should be small with respect to the context-switch time.
False
In asynchronous replication, each block is written locally and remotely before the write is considered complete.
False
In contiguous memory allocation, context switch would allocate more memory to the switching process
False
In contiguous memory allocation, context switch would allocate more memory to the switching process.
False
In contiguous memory allocation, the value of relocation register contains the range of logical address space
False
In dynamic allocation of contiguous process memory, worst-fit algorithm would produce smallest left-over holes
False
In dynamic allocations of contiguous process memory, worst-fit algorithm would produce smallest leftover holes
False
In general, virtual memory decreases the degree of multiprogramming in a system
False
In general, virtual memory decreases the degree of multiprogramming in a system.
False
In general- virtual memory decreases the degree of multiprogramming in a system.
False
In the dining philosophers problem, there is a possibility of deadlock but not livelock.
False
Initial value of a semaphore must be positive
False
Initial value of a semaphore must be positive.
False
Interrupts, signals, messages, and information in IO buffers are all examples of reusable resources
False
Inverted page tables require each process to have its own page table.
False
It is possible to have a deadlock involving only one single threaded processes
False
It is possible to have a deadlock involving only one single-threaded processes.
False
LOOK disk head scheduling offers no practical benefit over SCAN disk head scheduling.
False
Linux distinguishes between processes and threads.
False
Linux mostly uses atomic integers to manage race conditions within the kernel
False
Linux mostly uses atomic integers to manage race conditions within the kernel.
False
Load balancing algorithms have no impact on the benefits of processor affinity.
False
Load balancing is typically only necessary on systems with a common run queue
False
Memory compression is faster than swapping pages to hard disks, but slower than swapping pages to SSDs.
False
Memory management by segmentation doesn't have the problem of external fragmentation
False
Mobile OS typically support swapping
False
Mobile operating systems typically support swapping.
False
Monitors are a theoretical concept and are not practiced in modern programming languages
False
Mutex locks and counting semaphores are essentially the same thing.
False
Non-uniform memory access has little effect on the performance of a virtual memory system
False
Non-uniform memory access has little effect on the performance of a virtual memory system.
False
On a UNIX system, writes to an open file are not immediately visible to other users who also have the same file open.
False
On a read operation, the device driver first checks if the data already available in the buffer cache.
False
On systems that provide it- vfork() should always be used instead of fork().
False
Only a fraction of a process's working set needs to be stored in the TLB
False
Only a fraction of a process's working set needs to be stored in the TLB.
False
Ordering resources and requiring the resources to be acquired in order prevents the circular wait from occurring and therefore prevents deadlock from occurring.
False
Performance of allocation method is determined only by the used allocation algorithm:
False
Peterson's algorithm uses semaphores to solve the critical section problem
False
Peterson's algorithm uses semaphores to solve the critical section problem.
False
Protocols to prevent hold-and-wait conditions typically also prevent starvation.
False
Providing a preemptive- priority-based scheduler guarantees hard real-time functionality.
False
Race conditions won't happen in a single processor system
False
Reentrant code cannot be shared.
False
Shared memory is a more appropriate IPC mechanism than message passing for distributed systems.
False
Sharing of memory-mapped sections of memory among multiple processes can be efficiently realized without the usage of virtual memory:
False
Sockets are considered a high-level communications scheme.
False
Solaris and Windows assign higher-priority threads/tasks longer time quantums and lower-priority tasks shorter time quantums.
False
Solaris uses both a local and global page replacement policy.
False
Solid state disks are considered volatile storage.
False
Standard swapping involves swapping in pages of processes instead of entire processes.
False
System calls can be run in either user mode or kernel mode.
False
Systems using a one-to-one model (such as Windows- Solaris- and Linux) schedule threads using process-contention scope (PCS).
False
Task parallelism distributes threads and data across multiple computing cores.
False
The deadlock-free solution of the dining philosophers problem eliminates the possibility of starvation
False
The difference between a program and a process is that a program is an active entity while a process is a passive entity.
False
The exec() system call creates a new process.
False
The length of a time quantum assigned by the Linux CFS scheduler is dependent upon the relative priority of a task.
False
The main drawback of General Graph Directory is performance overhead from possibility of traversing shared files multiple times:
False
The operating system kernel consists of all system and application programs in a computer.
False
The signal() operation of a semaphore has no effect if there is no thread in the wait queue of the semaphore
False
The single benefit of a thread pool is to control the number of threads.
False
The value of a counting semaphore can range only between 0 and 1
False
The value of a counting semaphore can range only between 0 and 1.
False
There is a 1:1 correspondence between the number of entries in the TLB and the number of entries in the page table
False
There is a 1:1 correspondence between the number of entries in the TLB and the number of entries in the page table.
False
Traditional synchronization is always much faster than CAS-based synchronization.
False
UNIX does not allow users to escalate privileges to gain extra permissions for a restricted activity.
False
When a layered structure is used for file-system implementation, risk of duplication of code increases:
False
When a thread invokes the signal() method of a condition variable, all threads blocked on that condition variable are unblocked.
False
When the owner of a mutex lock invokes pthread mutex unlock(), all threads blocked on that mutex's lock are unblocked.
False
Windows uses both a local and global page replacement policy.
False
One advantage of HDDs over SSDs is
HDDs are cheaper per megabyte than SSDs.
One necessary condition for deadlock is ______, which states that a process must be holding one resource and waiting to acquire additional resources.
Hold and Wait.
One necessary condition for deadlock is ____, which states that a process must be holding one resource and waiting to acquire additional resources.
Hold and wait
_____ is the dynamic storage-allocation algorithm which results in the largest leftover hole in memory.
Worst fit
Which of the following is a principle that can improve the efficiency of I/O?
Move processing primitives into hardware
One necessary condition for deadlock is ____, which states that at least one resource must be held in a nonsharable mode.
Mutual Exclusion
Which of these conditions is easiest to give up to prevent deadlocks? Select one: a.Mutual exclusion (make everything sharable) b. Hold and wait (must get all resources at once) c.No preemption (resources can be taken away) d.Circular wait (total order on resource requests) e.None of the above
No preemption (resources can be taken away)
In a wait-for-graph, A) a resource may have multiple instances. B) a deadlock implies the existence of a cycle, but a cycle does not necessarily imply a deadlock. C) a cycle implies deadlock, but not every deadlock results in a cycle. D) None of the above.
None of the above
Assuming m is the number of resource types and n is the number of processes, what is the time complex of the banker's algorithm?
O(mn^2)
A(n) ____ file is a sequence of bytes organized into blocks understandable by the system's linker.
Object
The UNIX file system uses which of the following consistency semantics?
Writes to an open file by a user are visible immediately to other users that have the file open at the same time
The UNIX file system uses which of the following consistency semantics?
Writes to an open file by a user are visible immediately to other users that have the file open at the same time.
A closed chain of processes exists, such that each process holds at least one resource needed by the next process in the chain is the condition of __________ .
circular wait
The __________ condition can be prevented by defining a linear ordering of resource types.
circular wait
Absolute code can be generated for ____.
compile-time binding
In memory compression,
compression ratio needs to be balanced with the compression time.
A _________ resource is one that can be created and destroyed.
consumable
The ____ register of an I/O port can be written by the host to start a command or to change the mode of a device.
control
________ 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.
copy-on-write
A(n) _______ refers to where a process is accessing/updating shared data.
critical section
A(n) _________ refers to where a process is accessing/updating shared data
critical section
_______ refers to where a process is accessing/updating shared data.
critical section
Which of the following is not considered a classification of users in connection with each file?
current user
__________ allows the three necessary conditions but makes judicious choices to assure that the deadlock point is never reached.
deadlock avoidance
Requested resources are granted to processes whenever possible with _________ .
deadlock detection
_________ strategies are very conservative and solve the problem of deadlock by limiting access to resources and by imposing restrictions on processes.
deadlock prevention
On media that uses constant linear velocity, the
density of bits per track is uniform
On media that uses constant linear velocity, the ____.
density of bits per track is uniform
I/O control level consists of:
device drivers, interrupt handlers
A spinlock ____.
does not require a context switch when a process must wait on a lock
The _________ is useful in sending a signal to a thread indicating that a particular event has occurred.
event object
A deadlocked state occurs whenever ____.
every process in a set is waiting for an event that can only be caused by another process in the set
app.exe is an example of a(n) _____.
executable file
An instruction that executes atomically ____
executes as a single, uninterruptible unit
An instruction that executes atomically ____.
executes as a single, uninterruptible unit
The _____ binding scheme facilitates swapping.
execution time
_________ is the method of binding instructions and data to memory performed by most general-purpose operating systems
execution time binding
Memory-mapped I/O works well with devices that are characterized by:
fast response times
Once the processes have progressed into the __________ , those processes will deadlock.
fatal region
What is a significant drawback of hash table:
fixed size
In Peterson's solution, the ____ variable indicates if a process is ready to enter its critical section.
flag[i]
The advantage of continuous allocation lies in:
flexibility
The roll out, roll in variant of swapping is used ____.
for priority-based scheduling algorithms
Belady's anomaly states that ____.
for some page replacement algorithms, the page-fault rate may increase as the number of allocated frames increases
One necessary condition for deadlock is ____, which states that a process must be holding one resource and waiting to acquire additional resources.
hold and wait
One necessary condition for deadlock is _________, which states that a process must be holding one resource and waiting to acquire additional resources
hold and wait
The _________ condition can be prevented by requiring that a process request all of its required resources at one time and blocking the process until all requests can be granted simultaneously.
hold and wait
Three conditions of policy must be present for a deadlock to be possible: mutual exclusion, no preemption, and _________ .
hold and wait
Another problem related to deadlocks is ____________.
indefinite blocking
In the Linux VFS architecture, a(n) ____ object represents an individual file.
inode
On UNIX systems, the data structure for maintaining information about a file is a(n) _____.
inode
A mutex lock ____.
is essentially a boolean variable
A semaphore ____.
is essentially an integer variable
A RAID structure ____.
is primarily used to ensure higher data reliability
In JAVA, when a thread calls notify(), an arbitrary thread T from the list of threads in the wait set
is set to runnable state and is moved from the wait set to entry set where it competes for the lock with the other threads in the entry set.
Optimal page replacement algorithm _________
is used mostly for comparison with other page-replacement schemes
The witness software product is a ____.
lock-order verifier that uses mutual-exclusion locks to protect critical sections
A _____ is used on UNIX systems at the beginning of some files to roughly indicate the type of the file.
magic number
A(n) ___________ is a sequence of read-write operations that are atomic.
memory transaction
The mapping of a logical address to a physical address is done in hardware by the ________.
memory-management-unit (MMU)
A ___ type presents a set of programmer-defined operations that are provided mutual exclusion within it.
monitor
A(n) ___ type presents a set of programmer-defined operations that are provided mutual exclusion within it.
monitor
With _________ only one process may use a resource at a time and no process may access a resource unit that has been allocated to another process.
mutual exclusion
One necessary condition for deadlock is ______, which states that a resource can be released only voluntarily by the process holding the resource
no preemption
Systems in which memory access times vary significantly are known as __________.
non-uniform memory access
A(n) ____ file is a sequence of bytes organized into blocks understandable by the system's linker.
object
Which classifications of users are typically used in access-control list to condense its length:
owner, group, universe
The re-recordable CD-RW and DVD-RW are examples of ____ disks.
phase change
In systems that support virtual memory, ____.
physical memory is separated from logical memory.
Device drivers
present a uniform device- access interface to the I/O subsystem
To handle deadlocks, operating systems most often ____.
pretend that deadlocks never occur
To handle deadlocks, operating systems most often _____.
pretend that deadlocks never occur
What is the correct order of operations for protecting a critical section using a binary semaphore?
wait() followed by signal()
Windows uses a local page replacement policy _____.
when a process exceeds its working set maximum
The _________ is an approximation of a program's locality
working set
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.
Operations on atomic integers do not require locking.
_____ is not a technique used for handling critical sections in operating system kernels. Select one: a. Nonpreemptive kernels b. Disabling interrupts c. Peterson's algorithm d. Spin locks
Peterson's algorithm
____ is/are not a technique for managing critical sections in operating systems.
Peterson's solution
_____ is a technique for handling critical sections in operating systems.
Peterson's solution
_____ is not a technique for handling critical sections in operating systems.
Peterson's solution
_____ is/are a technique for managing critical sections in operating systems.
Peterson's solution
_____ is/are not a technique for managing critical sections in operating systems.
Peterson's solution
Inspired by the concept of co-routines, a _________ is a circular buffer allowing two processes to communicate on the producer-consumer model.
Pipe
One of the most significant contributions of UNIX to the development of operating systems is the _________ .
Pipe
The strategy of deadlock _________ is to design a system in such a way that the possibility of deadlock is excluded.
Prevention
____ occurs when a higher-priority process needs to access a shared data structure that is currently being accessed by a lower-priority process.
Priority inversion
____________ occurs when a higher-priority process needs to access a data structure that is currently being accessed by a lower-priority process
Priority inversion
____________ occurs when a higher-priority process needs to access a data structure that is currently being accessed by a lower-priority process.
Priority inversion
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?
R2, R1, R3.
____ I/O accesses a block device as a simple array of blocks.
Raw
________ is/are not considered a difficulty when considering file sharing.
Reliability
A(n) ____ is a front-end processor that multiplexes the traffic from hundreds of remote terminals into one port on a large computer
Terminal Concentrator
The surface of a magnetic disk platter is divided into ____.
Tracks
A character-stream device ____.
Transfers data a byte at a time
A Solaris interactive thread with a time quantum of 80 has a higher priority than an interactive thread with a time quantum of 120
True
A boot-control block in NTFS is called partition boot sector:
True
A file on a Solaris system with permissions -rwx--x--x+ is an example of both access-control lists as well as owner/group/universe protection.
True
A link in a directory is being resolved by using path name to locate the real file and thus can be seen as an indirect pointer to that file:
True
A multicore system allows two (or more) threads that are in compute cycles to execute at the same time
True
A mutex is used to ensure that only one thread at a time can access the resource protected by the mutex
True
A non preemptive kernel is safe from race conditions on kernel data structures
True
A nonpreemptive kernel is safe from race conditions on kernel data structures.
True
A page fault must be preceded by a TLB miss
True
A page fault must be preceded by a TLB miss.
True
A page-fault must be preceded by a TLB miss
True
A reentrant lock allows for granting the lock to the longest-waiting thread when unlock() is called.
True
A signal is similar to a hardware interrupt but does not employ priorities
True
A socket is identified by an IP address concatenated with a port number.
True
A thread will immediately acquire a dispatcher lock that is the signaled state.
True
A traditional(or heavyweight) process has a single threadof control
True
A useful tool in characterizing the allocation of resources to processes is the resource allocation graph
True
All deadlocks involve conflicting needs for resources by two or more processes
True
All files in a single-level directory must have unique names.
True
All processes in UNIX first translate to a zombie process upon termination.
True
Although caching and buffering are distinct functions, sometimes a region of memory can be used for both purposes.
True
Amdahl's Law describes performance gains for applications with both a serial and parallel component.
True
An advantage of transactional memory system is that the developer doesn't have to worry about implementing atomicity.
True
An atomic operation executes without interruption and without interference
True
Application programmers typically use an API rather than directory invoking systems calls
True
Both deadlock prevention and deadlock avoidance techniques ensure that the system will never enter a deadlocked state.
True
Both the test_ and_set() instruction and compare_and_swap() instruction are executed atomically.
True
Busy waiting refers to the phenomenon that while a process is in its critical section, any other process that tries to enter its critical section must loop continuously in the call to acquire the mutex lock.
True
CSTREAMS is the preferred method for writing protocols and device drivers in UNIX variants.
True
Circular wait is a necessary but not a sufficient condition for deadlock
True
Deadlock avoidance requires knowledge of future process resource requests
True
Deadlock is permanent because none of the events is ever triggered
True
Deadlock occurs when every thread in a set is blocked waiting for an event that can be caused only by another thread in the set, while livelock occurs when a thread continuously attempts an action that fails.
True
Deferred cancellation is preferred over asynchronous cancellation.
True
Each thread has its own register set and stack.
True
Every object in Java has associated with it a single lock.
True
External fragmentation does not occur in a paging system
True
External fragmentation does not occur in a paging system.
True
Flash memory is slower than DRAM but needs no power to retain its contents
True
For a single-processor system, there will never be more than one process in the Running state.
True
In the enhanced second chance algorithm, which of the following ordered pairs represents a page that would be the best choice for replacement?
(0,0)
A system can recover from a deadlock by A) aborting one process at a time until the deadlock cycle is eliminated. B) aborting all deadlocked processes. C) preempting some resources from one or more of the deadlocked threads. D) All of the above.
All of the above
An interrupt priority scheme can be used to ____. A) allow the most urgent work to be finished first B) make it possible for high-priority interrupts to preempt the execution of a low priority interrupt C) defer the handling of low-priority interrupt without masking off all interrupts D) All Answers are Correct
All of the above
An interrupt priority scheme can be used to ____. A) allow the most urgent work to be finished first B) make it possible for high-priority interrupts to preempt the execution of a low priority interrupt C) defer the handling of low-priority interrupt without masking off all interrupts D) All of the above
All of the above
In deadlock prevention by denying hold-and-wait condition, A) resource utilization may below. B) starvation is possible. C) whenever a thread requests a resource, it does not hold any other resources. D) All of the above.
All of the above
Most operating systems choose to ignore deadlocks, because A) handling deadlocks is expensive in terms of performance and resources. B) deadlocks occur infrequently. D) methods used to recover from livelock may be put to use to recover from deadlock. D) All of the above.
All of the above
To recover from a deadlock using resource preemption, A) the order of resources and processes that need to be preempted must be determined to minimize cost. B) if a resource is preempted from a process, the process must be rolled back to some safe state and restarted from that state. C) ensure that starvation does not occur from always preempting resources from the same process. D) All of the above.
All of the above
In Linux, A) pages in active list may be moved to inactive list. B) pages in inactive list may be moved to active list. C) pages in inactive list are may be reclaimed for the free list. D) All of the above.
All the above
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
All the above
Given what we currently know about memory, what must we do during a context switch?
Allocate memory to the switching process
Which of the following statements is true?
An unsafe state may lead to a deadlocked state
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.
An unsafe state may lead to a deadlocked state
Which of the following statements is true?
An unsafe state may lead to a deadlocked state.
A solution to the critical section problem does not have to satisfy which of the following requirements?
Atomicity
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?
Available
Which of the following statements is false with regard to allocating kernel memory?
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.
_____ is the dynamic storage-allocation algorithm which results in the smallest leftover hole in memory.
Best fit
A _____ could be preempted from a process.
CPU
A____ could be preempted from a process
CPU
DMA controllers ____.
Can steal memory access cycles from the main CPU
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.
Circular wait
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?
Condition variables and semaphores are never used in place of an adaptive mutex.
A volume control block ____.
Contains information such as the number of blocks in a partition, size of the blocks, and free-block and FCB count and pointers
Which of the following allocation methods ensures that only one access is needed to get a disk block using direct access?
Contiguous Allocation
The ____ register of an I/O port can be written by the host to start a command or to change the mode of a device.
Control
A(n)_____refers to where a process is accessing/updating shared data.
Critical Section
NFS views a set of interconnected workstations as a set of ____.
Independent machines with independent file systems
A(n) ____ page table has one page entry for each real page (or frame) of memory.
Inverted
Which of the following is true of the direct-access method?
It allows programs to read and write records in no particular order.
Which of the following is NOT a benefit of allowing a program that is only partially in memory to execute?
It can avoid deadlocks from happening
What is the purpose of the mutex semaphore in the implementation of the bounded-buffer problem using semaphores
It ensures mutual exclusion
What is the purpose of the mutex semaphore in the implementation of the bounded-buffer problem using semaphores?
It ensures mutual exclusion
What is the purpose of the mutex semaphore in the implementation of the bounded-buffer problem using semaphores?
It ensures mutual exclusion.
A calling thread becomes the owner of a lock when ______________.
It enters a synchronized method.
A Java thread may release a lock under which of the following circumstances?
It exits a synchronized method.
The free-space list can be implemented using a bit vector approach. Which of the following is a drawback of this technique?
It is not feasible to keep the entire list in main memory for large disks.
Which of the following is true of compaction?
It is possible only if relocation is dynamic and done at execution time.
Which of the following is true of the tree-structured directory structure?
It is the most common directory structure.
Which of the following statements regarding the WAFL file system is incorrect?
It provides little replication.
_________ is the page replacement algorithm implemented on most systems.
LRU
Which algorithm is considered reasonable for managing a buffer cache?
Least-recently-used (LRU)
______ is a secure, distributed naming mechanism.
Lightweight directory-access protocol (LDAP)
Which of the following is the simplest method for implementing a directory?
Linear List
The file-allocation table (FAT) used in MS-DOS is an example of ____
Linked Allocation
An address generated by a CPU is referred to as a ____.
Logical address
An address generated by a CPU is referred to as a _________
Logical address
______ includes all of the file system structure, minus the actual contents of files.
Metadata
A ___ type presents a set of programmer-defined operations that are provided mutual exclusion within it.
Monitor
A _________ resource is one that can be safely used by only one process at a time and is not depleted by that use.
Reusable
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?
Several processes could be active in their critical sections at the same time.
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?
Several processes could be active in their critical sections at the same time.
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(). Whatwould be a possible outcome of this?
Several processes could be active in their critical sections at the same time.
Which of the following is not a reason explaining why mobile devices generally do not support swapping?
Small size of mobile applications do not require use of swap space.
A _____ is a view of a file system before the last update took place
Snapshot
A(n) ____ file is a sequence of subroutines and functions.
Source
The most common technique used for protecting a critical section in Linux is the __________ .
Spinlock
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.
Spinlocks can be used to prevent busy waiting in the implementation of semaphore
A(n) ____ is a buffer that holds output for a device that cannot accept interleaved data streams
Spool
Suppose that a system is in an unsafe state. It is possible for the processes to complete their execution without entering a deadlocked state
State
The _________ of the system reflects the current allocation of resources to processes.
State
A sense key reports on the failure of a SCSI device by ____.
Stating the general nature of the failure
The ____ is the number of entries in the TLB multiplied by the page size.
TLB reach
Which of the following is true of a blocking system call?
The execution of the application is suspended when the call is issued.
Which of the following statements regarding the ARM architecture are false?
The micro TLB must be flushed at each context switch.
Which of the following statements is false with regard to Solaris memory management?
The speed at which pages are examined (the scanrate) is constant.
Which one of the following statements are incorrect when a Java thread invokes the wait() method?
The thread that has been waiting the longest becomes the new owner of the lock.
Which of the following is NOT true regarding a condition variable, e.g. x? a. A condition variable allows processes to be suspended and wait in the critical section. b. x.wait() means that the process invoking this operation is suspended until another process invokes x.signal() c. The x.signal() operation resumes exactly one suspended process if there are any. d. If no process is suspended, then the x.signal() operation still affects the state of x by incrementing its internal value.
The x.signal() operation resumes exactly one suspended process if there are any.
Which of the following is considered a benefit when using the slab allocator?
There is no memory fragmentation.
_____ occurs when a process spends more time paging than executing.
Thrashing
The system-wide open-file table contains
a copy of the file control block of each open file
In a system resource-allocation graph, ____.
a directed edge from a process to a resource is called a request edge
Benefit(s) of using STREAMS is (are) A) a module can be used by more than one device. B) STREAMS I/O is synchronous. C) number of modules in STREAMS is constant. D) all of the above.
a module can be used by more than one device.
A cycle in a resource-allocation graph is ____.
a necessary and sufficient condition for a deadlock in the case that each resource has exactly one instance
A file handle is:
a pointer to an entry in the per-process file-system table
A page fault occurs when
a process tries to access a page that is not loaded in memory.
In FAT used in MS-DOS,
a string preceding the colon that identifies the storage device.
In a dynamically linked library, ____.
a stub is included in the image for each library-routine reference
What causes lack of support for efficient direct access in linked allocation:
absence of FAT
Host-attached storage is ____.
accessed via local I/O ports
What is the correct order of operations for protecting a critical section using mutex locks?
acquire() followed by release()
A(n) ______ matches the process with each entry in the TLB.
address-space identifier
In modern operating systems, dynamic loading and unloading allows A) adding new I/O devices after the system has already been booted. B) adding new I/O devices without recompiling the kernel. C) updating existing devices drivers without recompiling the kernel. D) all of the above.
all of the above
Which of the following data structures is appropriate for placing into its own segment?
all of the above
Read or write performance of a hard disk drive depends on A) bit transfer rate B) seek time C) rotational latency D) all of the above
all the above
A page address extension (PAE) in IA-32
allows 32-bit processors to access a physical address space larger than 4 GB.
The vfork() system call in UNIX ____.
allows the child process to use the address space of the parent
An acyclic-graph directory structure ____.
allows the sharing of subdirectories and files.
The path name /home/people/os-student/chap10.txt is an example of
an absolute path name
UNIX systems allow groups to be created and modified by:
any superuser
Pthreads can be implemented
at the user level or inside the operating system kernel
The strategy of resource allocation denial is referred to as the ___________ .
bankers algorithm
In ARM architecture, address translation
begins at the micro-TLB level.
A shared lock ____.
behaves like a reader lock
An exclusive lock ____.
behaves like a writer lock
The OpenMP #pragma omp critical directive ____.
behaves much like a mutex lock
The OpenMP #pragma omp critical directive ___________.
behaves much like a mutex lock
Two types of atomic operations are defined in Linux: integer operations and __________ .
bitmap operations
Transfers between memory and disk are performed a ____.
block at a time
_________ occurs when higher-priority process needs to access a shared data structure that is currently being accessed by a lower-priority process
priority inversion
A program invocation, including the address space and resources required to run the program is a __________ object.
process
The _____ allocation algorithm allocates available memory to each process according to its size.
proportional
____ I/O accesses a block device as a simple array of blocks.
raw
Linux provides three types of semaphore facilities in the kernel: binary semaphores, counting semaphores, and __________ .
reader-writer semaphores
The _________ allows multiple threads to have simultaneous read-only access to an object protected by the lock
readers/writer lock
The first readers-writers problem ____.
requires that no reader will be kept waiting unless a writer has already obtained permission to use the shared database.
The _________ is a directed graph that depicts a state of the system of resources and processes, with each process and each resource represented by a node.
resource allocation graph
A race condition ____
results when several threads try to access and modify the same data concurrently
A race condition ____.
results when several threads try to access and modify the same data concurrently
Examples of __________ include processors, I/O channels, main and secondary memory, devices, and data structures such as files, databases, and semaphores.
reusable resources
With segmentation, a logical address consists of _____.
segment number and offset
With segmentation scheme, a logical address consists of _________
segment table and offset
The simplest file access method is ____.
sequential access
The SSTF scheduling algorithm ____.
services the request with the minimum seek time
When using semaphores, a process involves 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?
several processes could be active in their critical section at the same time
The fastest form of interprocess communication provided in UNIX is __________ .
shared memory
A __________ is a software mechanism that informs a process of the occurrence of asynchronous events.
signal
A call to pthread_cond_signal()
signals one thread waiting on the condition variable, but does not release the mutex lock.
A(n) ____ is a buffer that holds output for a device that cannot accept interleaved data streams.
spool
A sense key reports on the failure of a SCSI device by ____.
stating the general nature of the failure
A _____ is a private network connecting servers and storage units.
storage-area network
Which of the following is true of compaction?
t is possible only if relocation is dynamic and done at execution time.
Standard swapping is generally not used in contemporary operating systems, because
the amount of time required to move entire processes between memory and the backing store is prohibitive.
Prepaging can be an advantage, because
the cost of using prepaging is less than the cost of servicing the corresponding page faults.
A mount point is _____.
the location within the file structure where the file system is to be attached.
When producer file creates a view of the memory-mapped file in its virtual address space and passes the last three parameters non-zero values, it indicates that:
the mapped view contains only a subsection of a file
In an environment where several processes may open the same file at the same time, ____.
the operating system typically uses two internal tables called the system-wide and per-process tables to keep track of open files
_________ occurs when a process spends more time paging than executing.
thrashing
An executable entity within a process is a __________ object.
thread
A character-stream device ____.
transfers data a byte at a time
Swap space management ____.
tries to provide the best throughput for the virtual memory system
Path name of the file is composed of:
user name, file name
In a functional programming language,
value of a variable is immutable.
What is a popular solution to increase the speed of linear list of directory entries:
vector of file header pointers
