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Exam 2 csce 3600 questions well
answered graded A+
The SELECT function allows the servers to deal with blocking calls by identifying sockets that are ready for use - correct answer ✔✔True In a single processor system, all the threads execute in interleaved fashion(=though in no particular order) sharing the CPU - correct answer ✔✔True System calls or library routines are called thread safe if they can be called from multiple threads simultaneously and always produce correct results - correct answer ✔✔True Each process has its own ready queue - correct answer ✔✔False Datagram sockets do not require the client to establish a connection with the server before sending messages to the server - correct answer ✔✔False preemptive scheduling algorithms may results in starvation - correct answer ✔✔True The degree of multi program is controller by the CPU scheduler - correct answer ✔✔False When the PTHREAD_EXIT system call is issued by a thread, all threads associated with that process are terminated - correct answer ✔✔False A child process created by the FORK system call inherits its parent's process id - correct answer ✔✔False
condition variable allows a thread to block itself until specified data reaches a redefined state - correct answer ✔✔True A thread will block if the semaphore value is less than or equal to zero when a SEM_WAIT is issued - correct answer ✔✔True As the time slice becomes shorter, the more the RR scheduler behaves like the FIFO scheduler - correct answer ✔✔False The privilege mode must be changed to "kernel mode" when doing a system call - correct answer ✔✔True One of the guarantees offered by the PIPE IPC system call is that__________ - correct answer ✔✔All writes up to 4K bytes to the pipe are atomic turnaround time refers to the amount of time___________ - correct answer ✔✔Needed to executes a particular process _______ refers to a situation in which a process is ready to execute, but is continuously denied access to a processor in deference to other processes - correct answer ✔✔Starvation Consider the following code Int main() { If (fork() > 0)
Which of the following are virtually shared by threads within a single process? In other words, which are instantiated per process instead of per thread? - correct answer ✔✔Code / program text Which of the following is true of multilevel queue scheduling - correct answer ✔✔Each queue has its own scheduling algorithm. A process control block ______ - correct answer ✔✔includes information on the process's state In scheduling algorithms, the term "aging" involved _______ - correct answer ✔✔gradually increasing the priority of a process so thar the process will eventually execute Which scheduling algorithm suffers from the convoy effect - correct answer ✔✔FIFO
- consider the following program int main() { struct sockaddr_un svr; int fd_svr = socket(AF_UNIX, SOCK_STREAM, 0); svr.sun_family = AF_UNIX; strcpy(svr.sun_path, "svr_sock"); bind(fd_svr, (struct sockaddr*)&svr, sizeof(svr)); listen(fd_svr, 3); return 0;
What is the length of the queue for pending connections ( i.e partially completed connections) in this program - correct answer ✔✔ 3 ______are all valid process states - correct answer ✔✔running, blocked and waiting What will be the output of the following code? #include <sys/types.h> #include <stdio.h> int main() { pid_t pid = fork(); if (pid>0) printf("parent"); else printf("child"); return 0; } - correct answer ✔✔can be childparent or parentchild
consider the following set of processes arriving at the same time with their respective CPU burst time (in milliseconds): process CPU-Burse Time P1 12 P2 3 P3 6 if the processes are scheduled round robin (RR) in the order P1, P2, then P3, which of the following time slice lengths would give the best average waiting time - correct answer ✔✔3 ms in Linux, which system call causes the parent parent process to suspend execution until the child process has completed? - correct answer ✔✔wait a parser will check to see that input is semantically correct - correct answer ✔✔false Child processes, which are exact copies if their parents, can change variables in its parent process - correct answer ✔✔False a new process ID is created when the EXEC() function is called - correct answer ✔✔false the following regular expressions are exactly equivalent: y|z (y|z)* - correct answer ✔✔false
two UNIX/LINUX processes may simultaneously have open file descriptors that refer to the same open file description - correct answer ✔✔true INET domain sockets can only send messages to a different machine - correct answer ✔✔false the following regular expressions are exactly equivalent: (0|1)? 0?|1? - correct answer ✔✔true the UNIX/LINUX operating system allows multiple processes per thread - correct answer ✔✔false a function is said to be thread-safe if it can be called from multiple thread without unwanted interaction between the threads - correct answer ✔✔true for a given mutex, if one or more threads are blocked on a call to PTHREAD_MUTEX_LOCK() and the thread that is holding the lock calls PTHREAD_MUTEX_UNLOCK(), exactly one of the blocked threads will be unlocked and thus able to lock the mutex - correct answer ✔✔true ______ is a Pthreads function that terminates the calling thread ans makes the value value_ptr available to any successful join with the terminating thread - correct answer ✔✔pthread_exit Consider concurrent programming via "threads". For which of the following information would each thread get its own unique copy? - correct answer ✔✔stack an application that allows two different machines to communicate using a socket requires _____________ - correct answer ✔✔one of the machines to implement a server socket and the other a client socket
which system call creates a copy of the file descriptor passes as an argument? - correct answer ✔✔dup SOCK_STREAM sockets are used by ______ processes. - correct answer ✔✔TCP Consider the following program int main() { char * cmd[4]; cmd[0] = "ls"; cmd[1] = NULL; int fd = open ("testfile", o_creat | o_trunc | o_wronly, 0600); dup2(? ,? ); execvp(cmd[0], cmd); perror("main"); } how would you fill in question if you want the output of "ls" to go into "testfile"? - correct answer ✔✔dup2(fd,1) the pthread_cond_signal() call is used to_________ - correct answer ✔✔wake up a sleeping thread waiting on the condition variable
consider the following snippet of code in a program pip=fork(); if (pid == 0) { ...... Assuming the fork system call us successful, what is purpose of the "if (pid == 0)" line? - correct answer ✔✔it checkes whether the process is the child or the parent process after the call to fork the ________ contains all the states necessary to run a program, such as the stack, text segment, data section, and heap - correct answer ✔✔user level context Three file descriptors associated with every UNIX/LINUX process are standard input, standard output, and _________________ - correct answer ✔✔standard error Which of the following is True regarding the relationship between processes and threads - correct answer ✔✔it takes far less time to create a new thread in an existing process than to create a new process Compiler optimization entails all of the following except _______ - correct answer ✔✔suppressing error messages
