OS Final CH 6-14

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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


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