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Final Exam Information: Exam questions will include MCQ, Short-Answer and Essay Type This exam will consists of 50 questions of different weights . Time limit will be 90 minutes to solve all questions. Question 1 Marks: 1 The queue contains a set of processes waiting for an I/O device. Answer: Question 2 Marks: 1 Kernel thread managers are implemented in the operating system Answer: True False Question 3 Marks: 1 One of the following is not an advantage of multiprocessor systems: Choose one answer. a. Increase throughput, that is the speed-up ratio with N processors is not N, however; rather, its less than N. b. Multiprocessor systems can cost less than equivalent multiple single-processor systems c. A failure of one processor will not halt the system , only slow it down d. They may come in device specific processors Question 4 Marks: 1 According to First-Comer,First-Served Scheduling algorithm, the average waiting time is * : Process Burst Time P1 24 P2 3 P3 3 * the number to the right of process name is the arrival order Answer: Question 5 Marks: 1 Mutually Exclusive means that if process Pi is executing in its critical section, all other processes can be executing in their critical sections freely Answer: True False Question 6 Marks: 1 Application programs define the ways in which computer resources are used to solve users’ computing problems. Answer: True False Question 7 Marks: 1 <!--[if !supportLists]-->1. <!--[endif]-->In resource allocation graph ,if graph contains no cycle that implies: Choose one answer. a. if only one instance per resource type, then deadlock b. if several instances per resource type, possibility of deadlock c. no deadlock Question 8 Marks: 1 CPU Utilization means: Choose one answer. a. Keep the CPU as busy as possible b. Large number of processes waiting in the ready queue c. The CPU is allocated to the process with the highest priority Question 9 Marks: 1 The average turnaround time for the processes with the FCFS scheduling algorithm: Process Burst Time Arrival Time Choose one answer. a. 10.53 P1 0.0 8 P2 0.4 4 P3 1.0 1 b. 33 c. 11 Question 10 Marks: 3 What are the three main purposes of an operating system? Answer: Trebuchet 1 (8 pt) Lang Path: Question 11 Marks: 1 Match the software with its correct type: Unix Operating System is a type of Choose... Compiler is a type of Choose... Windows Media Player is a type of Choose... Question 12 Marks: 1 In a Batch system: Choose one answer. a. Jobs are executed concurrently b. Jobs are executed immediately in a interactive mode c. Jobs are executed one after the other without the intervention of the user Question 13 Marks: 1 A software may trigger an interrupt by executing a special operation called a system call or a monitor call Answer: True False Question 14 Marks: 1 A process is said to be in a state when it is waiting to be assigned to the CPU. Answer: Question 15 Marks: 2 Explain the term context switch? Answer: Question 16 Marks: 1 <!--[if !supportLists]-->1. <!--[endif]-->Effective Access Time EAT = (1 – p) x memory access+ p x (???) Choose one answer. a. Page fault time b. restart overhead c. swap page out + swap page in Question 17 Marks: 1 Which of the following components of program state are shared across threads in a multithreaded process? Choose one answer. a. Register values and Heap memory b. Heap memory and Global variables c. Stack memory and Register values Question 18 Marks: 1 One solution to the problem of external fragmentation is : Answer: Question 19 Marks: 1 One of the following is not a Classical Problem of Process Synchronization : Choose one answer. a. The Bounded-Buffer Problem b. The Readers-Writers Problem c. Dinning Philosophers Problem d. Internal Fragmentation Question 20 Marks: 1 Multiprocessors have three main advantages : Increase Throughput Economy of scale Increase reliability Answer: True False Question 21 Marks: 1 Ignore the problem and pretend that deadlocks never occur in the system; even though this method is cheaper than deadlock prevention or deadlock detection, it is not being used by common operating systems. Answer: True False Question 22 Marks: 2 What is the difference between graceful degradation and fault tolerant in terms of increase the reliability of a computer system? Answer: Question 23 Marks: 1 Arrange according to storage unit capacity Largest Capacity Choose... Large Capacity Choose... Medium Capacity Choose... Small Capacity Choose... Smallest Capacity Choose... Question 24 Marks: 1 CPU scheduling criteria used to compare scheduling algorithm performance and efficiency. Some of these criteria are: Keeps CPU as busy as possible : Choose... One measure of the number of processes completed : Choose... The sum of the periods spent waiting to get into memory,waiting in the ready queue, executing on the CPU , and doing I/O: Choose... The sum of the periods spent waiting in the ready queue: Choose... The time a from submission of a request until the first answer to that request is produced: Choose... Question 25 Marks: 1 Backing store is a slow disk with small space to accommodate copies of memory images for users which also provides direct access to these memory images Answer: True False Question 26 Marks: 2 The memory is usually divided into two partitions :one is for _________ and the other is for _______________. * use a comma to separate the two answers Answer: Question 27 Marks: 1 Match the answers with the correct unit: Physical Addresses are generate by Choose... Logical Addresses are generated by Choose... Question 28 Marks: 1 <!--[if !supportLists]-->1. <!--[endif]-->Page Fault Rate 0 <=p <= 100 Answer: True False Question 29 Marks: 1 Deadlock can arise if following conditions hold simultaneously: Choose one answer. a. Mutual exclusion, Hold and wait, No preemption and Circular wait b. Mutual exclusion , progress and bounded waiting c. Mutual exclusion , request , hold and release Question 30 Marks: 1 One of the following is not a process control system call Choose one answer. a. End, abort b. Load, execute c. Open, close d. Wait for time Question 31 Marks: 3 Select the correct information that is associated with a process in its PCB (process control block): 1 Choose... 2 Choose... 3 Choose... 4 Choose... 5 Choose... 6 Choose... 7 Choose... Question 32 Marks: 1 Application Programming Interface is more difficult to work with than system calls Answer: True False Question 33 Marks: 1 <!--[if !supportLists]-->1. <!--[endif]-->First-fit and best-fit better than worst-fit in terms of: <!--[if !supportLists]--> <!--[endif]--> Choose one answer. a. Simple implementation b. speed and storage utilization c. works with all types of memory Question 34 Marks: 5 Explain how DMA( Direct Memory Access) reduces CPU overhead? Answer: Question 35 Marks: 1 A major problem with priority scheduling algorithm is : Answer: Question 36 Marks: 1 Match the number with the correct process state: 1 Choose... 2 Choose... 3 Choose... 4 Choose... Question 37 Marks: 1 The operating system structure that allow the kernel to provide core services then add certain features dynamically is: Choose one answer. a. Modules approach b. Microkernel approach c. Layered approach d. Simple structure Question 38 Marks: 1 According to Shortest Job First (SJF) Scheduling algorithm, the average waiting time is : Process Burst Time P1 6 P2 8 P3 7 P4 3 Answer: Question 39 Marks: 1 Using FIFO Page Replacement Algorithm , find the number of page faults to the following string using 3 frames: 7 0 1 2 0 3 0 4 2 3 0 3 Answer: Save w ithout submitting 0 Submit all and finish 5859,5857,5942,5922,5875,5951,5888,5937,5936,5916,5930,5944,5952,5860,5918,5941,5938,5920,5881,5953,5892,5917,593 Bottom of Form You are logged in as Mrs.Siba Dallal (Logout) Top of Form Marks: 1 Atomic operation means an operation that completes in its entirety without interruption. Answer: True False Question 2 Marks: 1 Set value of timer should be privileged instruction Answer: True False Question 3 Marks: 1 Switching from user to kernel mode should be privileged instruction. Answer: True False Question 4 Marks: 1 The system consisting of n processes {P0,P1,……Pn-1}, each process has a segment of code, called …………….. Answer: Question 5 Marks: 1 Starvation : A process may be removed from the semaphore queue in which it is suspended Answer: True False Question 6 Marks: 1 In the Bounded-Buffer Problem Semaphore mutex initialized to the value …... Choose one answer. a. N-1 b. 0 c. N d. 1 Question 7 Marks: 1 A GUI might “waste” CPU cycles, but it optimizes the user’s interaction with the system. Answer: True False Question 8 Marks: 1 Deadlock – two or more processes are waiting indefinitely for an event that can be caused by only one of the waiting processes. Answer: True False Question 9 Marks: 1 Deadlock can arise if following conditions hold simultaneously: Choose one answer. a. Mutual exclusion , request , hold and release b. Mutual exclusion, Hold and wait, No preemption and Circular wait c. Mutual exclusion , progress and bounded waiting Question 10 Marks: 1 The Internet is a LAN as the various computers are located at geographically different places and are connected by long-distance network links. Answer: True False Question 11 Marks: 1 CPU utilization is decreased if the overheads associated with context switching is minimized Answer: True False Question 12 Marks: 1 Access I/O device can be performed in user mode. Answer: True False Question 13 Marks: 1 To prevent race conditions, concurrent processes must be synchronized. Answer: True False Question 14 Marks: 1 The most complex scheduling algorithm is the multilevel feedback-queue algorithm. Answer: True False Question 15 Marks: 1 <!--[if !supportLists]-->1. <!--[endif]-->In resource allocation graph ,if graph contains no cycle that implies: Choose one answer. a. if several instances per resource type, possibility of deadlock b. if only one instance per resource type, then deadlock c. no deadlock The number of random questions required is more than are still available in the category! Question 17 Marks: 1 <!--[if !supportLists]-->1. <!--[endif]--> <!--[if !vml]--><!--[endif]-->The following allocation graph indicates safe state , there is no deadlock <!--[if !vml]--> <!--[endif]--> Answer: True False Question 18 Marks: 1 Under non-preemptive scheduling scheme the CPU switches from running to waiting state. Answer: True False Question 19 Marks: 1 Issue a trap instruction should be privileged instruction. Answer: True False Question 20 Marks: 1 In resource allocation graph ,request edge – directed edge Pi ---> Pj Answer: True False Question 21 Marks: 1 Desktop systems May run several different types of operating systems. Answer: True False Question 22 Marks: 1 In the Bounded-Buffer Problem Semaphore full initialized to the value ……. Choose one answer. a. N b. 1 c. 0 d. N-1 Question 23 Marks: 1 Computer System Components are Hardware, Operating system, and Applications programs. Answer: True False Question 24 Marks: 1 Race condition: The situation where several processes access – and manipulate shared data concurrently. The final value of the shared data depends upon which process finishes last. Answer: True False Question 25 Marks: 1 In the Readers-Writers Problem the data set is shared among a number of concurrent processes,………. only read the data set; they do not perform any updates, and the Writers can both read and write Answer: Question 26 Marks: 1 Concurrent access to shared data always results in data consistency. Answer: True Question 27 False Marks: 1 Modify entries in device-status table can be performed in user mode. Answer: True False Question 28 Marks: 1 CPU scheduling is the basis of multiprogrammed operating systems Answer: True False Question 29 Marks: 1 Where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular ordar in which the access take place is called………………………. Answer: Question 30 Marks: 1 Semaphores is a synchronization tool that requires busy waiting Answer: True False Question 31 Marks: 1 Parallel Systems are Multiprocessor systems with more than one CPU in close communication. Answer: True False Question 32 Marks: 1 The context switching overheads could be lowered by performing context switches infrequently. Answer: True False Question 33 Marks: 1 Producer and consumer processes are coupled by ……………… to allow asynchronous production and consumption. Answer: Question 34 Marks: 1 SJF scheduling is approximated by predicting the next CPU burst with an exponential average of the measured lengths of previous CPU bursts Answer: True False Question 35 Marks: 1 In resource allocation graph ,assignment edge – directed edge Rj ---> Ri Answer: True Question 36 Marks: 1 False Peterson’s Solution: Assume that the LOAD and STORE instructions are atomic; this means _____________ Choose one answer. a. Cannot be interrupted b. Some times interrupted c. Can be interrupted Question 37 Marks: 1 OS is a resource allocator that manages all resources Answer: True False Question 38 Marks: 1 Producer and consumer processes are coupled by a buffer to allow asynchronous production and consumption. The buffer can be _____________ Choose one answer. a. Bounded or unbounded b. Bounded c. Unbounded Question 39 Marks: 1 The statement “count++” may be implemented in machine language as: register1 = counter register1 = register1 - 1 counter = register1 Answer: True False Question 40 Marks: 1 I/O devices and the CPU can execute concurrently. Answer: True False Question 41 Marks: 1 The basic computing resources are CPU, memory, I/O devices. Answer: True False Question 42 Marks: 1 In RR scheduling, the time quantum should be small with respect to the context-switch time Answer: True False Question 43 Marks: 1 An operating system for a PC must be concerned with response time for an interactive user. Answer: True Question 44 Marks: 1 False In Bounded Buffer Problem the semaphore full is initialized to the value 1 Answer: True False Question 45 Marks: 1 Solution to Critical-Section Problem must satisfy mutual execution and progress and unbounded waiting Answer: True False Question 46 Marks: 1 A program could use timer interrupts to compute the current time. Answer: True False Question 47 Marks: 1 Ignore the problem and pretend that deadlocks never occur in the system; even though this method is cheaper than deadlock prevention or deadlock detection, it is not being used by common operating systems. Answer: True False Question 48 Marks: 1 Read the clock can be performed in user mode. Answer: True False Question 49 Marks: 1 Average turnaround time is minimized by executing the shortest tasks first. Answer: True False The number of random questions required is more than are still available in the category! Question 51 Marks: 1 OS is a control program that controls execution of programs to prevent errors, except errors caused by the user. Answer: True False Question 52 Marks: 1 What are three requirements must a solution to the critical-section problem satisfy? Choose one answer. a. progress b. All the choices are correct c. bounded waiting d. Mutual exclusion Question 53 Marks: 1 In the Bounded-Buffer Problem Semaphore empty initialized to the value …… Choose one answer. a. 0 b. 1 c. N d. N-1 Question 54 Marks: 1 The distinction between kernel mode and user mode function as a rudimentary form of protection (security) system. Answer: True False Question 55 Marks: 1 OS Features Needed for Multiprogramming are I/O routine, Memory management, Allocation of devices and CPU scheduling. Answer: True False Save w ithout submitting 0 Bottom of Form Submit all and finish 5637,5403,5411,5983,5644,5970,5414,5643,5887,5418,6003,5405,5640,5998,5888,5646,5891,5997,5417,5889,5409,5971,540