A virtual memory system uses First In First Out (FIFO) page replacement policy and allocates a fixed number of frames to a process. Consider the following statements. P : Increasing the number of page frames allocated to a process sometimes increases the page fault rate Q : Some programs do not exhibit locality of reference Which of the following is TRUE?
1. Both P and Q are true, and Q is the reason for P
2.Both P and Q are true, but Q is not the reason for P
3.P is false but Q is true
4.Both P and Q are false
Cancellation point is the point where ______
1.the thread can be cancelled – safely or otherwise doesn’t matter
2. the thread can be cancelled safely
3.the whole process can be cancelled safely
4.None of the mentioned
If multiple threads are concurrently searching through a database and one thread returns the result then the remaining threads must be ____
1.continued
2.cancelled
3. protected
4.None of the mentioned
If no frames are free, _____ page transfer(s) is/are required.
1.one
2.two
3.three
4.four
If the thread pool contains no available thread ______
1.the server runs a new process
2.the server goes to another thread pool
3.the server demands for a new pool creation
4.the server waits until one becomes free
Signals that occur at the same time, are presented to the process _______
1.one at a time, in a particular order
2.one at a time, in no particular order
3.all at a time
4.None of the mentioned
Thread pools limit the number of threads that exist at any one point, hence _______
1.not letting the system resources like CPU time and memory exhaust
2.helping a limited number of processes at a time
3.not serving all requests and ignoring many
4.None of the mentioned
When a process blocks the receipt of certain signals?
1.The signals are delivered
2. The signals are not delivered
3.The signals are received until they are unblocked
4.The signals are received by the process once they are delivered
When the target thread periodically checks if it should terminate and terminates itself in an orderly manner, it is called?
1.Asynchronous cancellation
2.Asynchronous cancellation
3.Sudden Termination
4.Deferred cancellation
A FIFO replacement algorithm associates with each page the _______
1.time it was brought into memory
2.size of the page in memory
3.page after and before it
4. All of the mentioned
A memory page containing a heavily used variable that was initialized very early and is in constant use is removed, then the page replacement algorithm used is ________
1. LRU
2.LFU
3. FIFO
4. none of the mentioned
A process can never be sure that a signal it has sent ________
1.has which identifier
2. has not been lost
3.has been sent
4.All of the Mentioned
A process is thrashing if _____
1.it is spending more time paging than executing
2.it is spending less time paging than executing
3.page fault occurs
4.swapping can not take place
A process refers to 5 pages, A, B, C, D, E in the order : A, B, C, D, A, B, E, A, B, C, D, E. If the page replacement algorithm is FIFO, the number of page frames is increased to 4, then the number of page transfers _________
1. decreases
2. increases
3.remains the same
4.None of the mentioned
A process refers to 5 pages, A, B, C, D, E in the order : A, B, C, D, A, B, E, A, B, C, D, E. If the page replacement algorithm is FIFO, the number of page transfers with an empty internal store of 3 frames is?
1.8
2.10
3.9
4.7
Because of virtual memory, the memory can be shared among ______
1.processes
2. threads
3. instructions
4.None of the mentioned
Cancelling a thread asynchronously ______
1. frees all the resources properly
2. may not free each resource
3. spoils the process execution
4. none of the mentioned
Each connection arriving at multi threaded servers via network is generally ______
1.is directly put into the blocking queue
2.is wrapped as a task and passed on to a thread pool
3.is kept in a normal queue and then sent to the blocking queue from where it is dequeued
4.None of the mentioned
Effective access time is directly proportional to ______
1.page-fault rate
2.hit ratio
3. memory access time
4.None of the mentioned
In FIFO page replacement algorithm, when a page must be replaced _______
1.oldest page is chosen
2.newest page is chosen
3.random page is chosen
4.none of the mentioned
In most cases, if a process is sent a signal while it is executing a system call _____
1.the system call will continue execution and the signal will be ignored completely
2.the system call is interrupted by the signal, and the signal handler comes in
3.the signal has no effect until the system call completes
4.None of the mentioned
In UNIX, the abort() function sends the ________ signal to the calling process, causing abnormal termination.
1.SIGTERM
2.SIGSTOP
3.SIGABORT
4.SIGABRT
In UNIX, the set of masked signals can be set or cleared using the ________ function.
1.sigmask
2.sigmaskproc
3.sigprocmask
4.sigproc
In UNIX, the ______________ system call is used to send a signal.
1.sig
2.send
3.kill
4.sigsend
Instead of starting a new thread for every task to execute concurrently, the task can be passed to a ____
1.process
2.thread pool
3. thread queue
4.None of the mentioned
Signals are identified by _____
1. signal identifiers
2.signal handlers
3. signal actions
4.none of the mentioned
Signals of a given type _______
1.are queued
2. are all sent as one
3.cannot be queued
4.None of the mentioned
Swap space exists in ______
1.primary memory
2.secondary memory
3.cpu
4.None of the mentioned
The aim of creating page replacement algorithms is to ______
1.replace pages faster
2. increase the page fault rate
3. decrease the page fault rate
4.to allocate multiple pages to processes
The number of the threads in the pool can be decided on factors such as ______
1.number of CPUs in the system
2.amount of physical memory
3.expected number of concurrent client requests
4. all of the mentioned
The pager concerns with the ______
1.individual page of a process
2.entire process
3.entire thread
4.first page of a process
The three ways in which a process responds to a signal are _______
1. ignoring the signal
2. handling the signal
3.performing some default action
4. All of the mentioned
The usefulness of signals as a general inter process communication mechanism is limited because _______
1.they do not work between processes
2.they are user generated
3. they cannot carry information directly
4.None of the mentioned
The usual effect of abnormal termination of a program is _______
1.core dump file generation
2.system crash
3. program switch
4.signal destruction
The _______ maintains pending and blocked bit vectors in the context of each process.
1.CPU
2.Memory
3.Process
4.kernel
Thread pools are useful when _______
1.when we need to limit the number of threads running in the application at the same time
2.when we need to limit the number of threads running in the application at the same time
3.when we need to arrange the ordering of threads
4.None of the mentioned
Thread pools help in ________
1.servicing multiple requests using one thread
2.servicing a single request using multiple threads from the pool
3.faster servicing of requests with an existing thread rather than waiting to create a new thread
4.None of the mentioned
Users _______ that their processes are running on a paged system.
1. are aware
2.are unaware
3. may unaware
4. none of the mentioned
What is the idea behind thread pools?
1.a number of threads are created at process startup and placed in a pool where they sit and wait for work
2.when a process begins, a pool of threads is chosen from the many existing and each thread is allotted equal amount of work
3.all threads in a pool distribute the task equally among themselves
4.None of the mentioned
What is the Optimal page – replacement algorithm?
1.Replace the page that has not been used for a long time
2.Replace the page that has been used for a long time
3.Replace the page that will not be used for a long time
4.None of the mentioned
What is Thread cancellation?
1.the task of destroying the thread once its work is done
2. the task of removing a thread once its work is done
3.the task of terminating a thread before it has completed
4.None of the mentioned
When a page is selected for replacement, and its modify bit is set _________
1.the page is clean
2. the page has been modified since it was read in from the disk
3.the page is dirty
4. the page has been modified since it was read in from the disk & page is dirty
When a program tries to access a page that is mapped in address space but not loaded in physical memory, then ______
1.segmentation fault occurs
2. fatal error occurs
3.page fault occurs
4.no error occurs
When a web page is loading, and the user presses a button on the browser to stop loading the page?
1.the thread loading the page continues with the loading
2.the thread loading the page does not stop but continues with another task
3.the thread loading the page is paused
4.the thread loading the page is cancelled
When one thread immediately terminates the target thread, it is called _______
1.Asynchronous cancellation
2.Systematic cancellation
3.Sudden Termination
4.Deferred cancellation
Which algorithm chooses the page that has not been used for the longest period of time whenever the page required to be replaced?
1.first in first out algorithm
2.additional reference bit algorithm
3.least recently used algorithm
4.counting based page replacement algorithm
Which of the following is not TRUE?
1. Processes may send each other signals
2.Kernel may send signals internally
3. A field is updated in the signal table when the signal is sent
4.Each signal is maintained by a single bit
Which of the following page replacement algorithms suffers from Belady’s Anomaly?
1. Optimal replacement
2.LRU
3.FIFO
4.Both optimal replacement and FIFO
Working set model for page replacement is based on the assumption of ____
1.modularity
2. locality
3.globalization
4.random access
____ is the concept in which a process is copied into the main memory from the secondary memory according to the requirement.
1. Paging
2.Demand paging
3.Segmentation
4.Swapping